Glenn Cardwell

Probiotics

2012-01-25T17:49:00.000-08:00

Peter Rogers asked me to write a few thoughts on probiotics. He tried a probiotic supplement for three months and didn’t see any benefit. His partner, however, felt an improvement and has stuck with them. You will have seen advertisements for both yogurt with Lactobacillus acidophilis and Bifidobacteria, as well as small bottles of supplemental live bacteria eg Yakult; these are examples of probiotics.

Probiotics is a general term for live bacteria that you consume in a food or as a supplement and which survive the passage all the way through the stomach and the small intestine to arrive safely in the large intestine. Here they settle down and become vigilant against evil forces.

Probiotics = back end health

Having a healthy bacterial balance in the large intestine is linked to normal bowel habits, healthy immunity, improved bioavailability of nutrients and possibly less risk of bowel cancer. With more healthy bacteria in the large intestine means that fewer nasty bacteria are able to get a foothold and cause internal turmoil. For example, the good bacteria like Lactobacillus produce organic acids that retard the growth of nasty bacteria such as Salmonella.

Where probiotics can be very helpful is when you get food poisoning or any condition with diarrhea, because you may have washed out a lot of healthy bacteria too. If you have been prescribed antibiotics then they may kill both the nasty bacteria causing your illness as well as some of the healthy bacteria in your bowel. In both cases taking some probiotics as a supplement or via a food like a yogurt with Lactobacillus bacteria will help re-establish the good bacteria in the bowel and make it difficult for pathogenic bacteria to take a hold. Some people today take probiotics in the precautionary hope it will prevent travelers diarrhea.

Athletes & probiotics

As an athlete’s training load increases so does their risk of illness, such as respiratory tract infections, so anything that has the potential to help the immune system may be able to keep an athlete healthy through heavy training and competition. There have been a few studies on the effects of probiotics and the results have been either positive or neutral.

One study found that a probiotic significantly reduced the severity and duration of respiratory tract illnesses in 20 male elite distance runners (Cox 2010). Another study of male and female athletes found that those taking a probiotic also had a much lower incidence of respiratory tract infections (Gleeson 2011). The authors speculated that this positive outcome might be due to higher levels of immunoglobulin A in those on the probiotic.

Other studies have not seen much difference and a review of all the evidence was not that enthusiastic about taking probiotics, although they did concede that they had potential for athletes undergoing heavy training. These studies are done in elite athletes who are likely to be under greater immune stress and may not have the same benefit for the generally fit and healthy.

The future

There will be more research on probiotics because there is a food industry that can benefit. The future will see more refined knowledge where we will recommend different probiotic bacteria types for different conditions. Whether you have Irritable Bowel Syndrome, food poisoning or have a family history of bowel cancer could determine the type of bacteria you take as a supplement.

What does it all mean?

Remember that for most of human history we never worried about probiotics. I doubt whether anyone mentioned “probiotic” at a dinner party until 1997. If you eat well, keep active, give to charity and overtake safely then there is an excellent chance that the bacteria in your large intestine are in perfect order, doing exactly as they should. In other words, good bacteria are naturally present.

You know your guts better than I do, indeed better than I want to know. So, I’ll leave you to make the decision whether to take probiotics. You might find little benefit like Peter did, or it could add a song to your day as his partner experienced. I’m like Peter. Happy to have yogurt with bacteria, but my resident gut bacteria are doing fine on their own with all that fibre I send their way each day. I don’t think they need “back up”.

Further reading in the Medical Journal of Australia] and the Sydney Morning Herald]

References:

Cox, A.J., et al 2010. British Journal of Sports Medicine 44 (4): 222-226

Gleeson, M., et al. 2011. International Journal of Sports Nutrition and Exercise Metabolism 21 (1): 55-64.

Eggs

2012-01-25T17:41:00.000-08:00

Rod Lees wrote and said: “There seems to be some mixed advice in relation to eggs and cholesterol.” You’re right Rod, and there has been for many years. It was conveniently thought that foods with cholesterol had the potential to raise blood cholesterol. We later realised that it was saturated fat and becoming blobby that made our cholesterol rise. It’s doubtful that it was the omelette you had for brekky.

As with most aspects of our body, genetics has an influence on cholesterol too, meaning you can eat superbly yet require the assistance of medication to get your cholesterol down.

The official word from the Heart Foundation is: Cholesterol in foods has only a small effect on your LDL cholesterol (that’s the nasty cholesterol – Ed), especially when compared with the much greater increase caused by saturated and trans fat in food.

Anyway, eggs are off the hook on the heart disease and blood cholesterol front. The Heart Foundation’s view on eggs is: Eggs are very nutritious. They contain good quality protein, lots of  vitamins and minerals, and mostly the healthier polyunsaturated fat.

They say that up to six eggs a week is fine. I couldn’t live without my mega-veg frittata with a touch of truffle oil. And if you ever hear about the cholesterol-free egg from the Araucana hen, someone is pulling your leg. All animal foods have cholesterol. That includes you and me. It is part of the cell wall.

More on eggs and nutrition http://eggs.org.au/health-and-nutrition here.

Novel by Glenn Cardwell

2012-01-12T04:06:00.000-08:00

I have written a novel. Why? Look, sometimes my life deviates beyond this nutrition thingy that has gripped me for three decades (+ 10% tax). About three years ago, while I strolled along a deserted beach, a dolphin came into the shallows and made a sign with its tail, which I took to mean “Write an novel young man.” I replied: “I’m not young anymore”, to which the dolphin’s tail semaphored “Well, you better get a wriggle on then sunshine.”

So here it is. It is available only as a download for your computer or digital reader.

Resistant Starch

2012-01-12T04:01:00.000-08:00

You have all heard of fibre, the mainly undigested bits in non-animal foods. You know us nutrition folk worship the stuff because it keeps you and me regular, slows down your eating, slows down digestion and it keeps your intestines healthy. If your bowels are happy, then the whole world seems much more friendly and ordered.

The fibre travels past your stomach and small intestines, and slides into the large intestine teeming with super-helpful and enthusiastic bacteria. These bacteria just love fibre. They will eat fibre all day, reproductively divide with big smiles, while producing compounds that kills bowel cancer cells.

OK, heard all that before; what about resistant starch?

Well, for a long time we thought that fibre was pretty much the only thing in food that did the job of making our waste wholesome, soft and bulky. Now we know that resistant starch (RS) is having a similar effect. It is not really fibre as we know it, although, like fibre, it doesn’t get digested and so the RS ends up in the large intestine. That is, RS is resistant to digestion.

Sometimes RS is called a “prebiotic” because it is used as a food source by the bacteria, much like inulin, a long chain of fructose molecules, which is often added to foods claiming to have “prebiotics”. Inulin occurs naturally in foods like asparagus, garlic, artichokes, bananas, leeks, onions, wheat, barley and rye. Don’t confuse prebiotics with probiotics, a topic I shall chat about in the next edition.

What food has RS?

Foods with high levels of RS include unprocessed whole grains, legumes, green bananas, and cooled, cooked potato (think potato salad). As a banana ripens the (long chain) starch begins to form (short chain) sugars making it sweeter and the RS levels decline. Despite that, about 85% of the remaining banana starch eaten makes it to the appendix where the large intestine begins. That’s why both ends of your digestive system love bananas.

Also, clever folk have been able to selectively breed grains to have a higher RS content. In Australia, you may have seen bread with “High Maize” added; it’s a type of corn with naturally high levels of RS. The “High Maize” starch is added to the bread to increase the fibre content.

Why would starch be resistant to digestion?

First know this - RS is composed of long chains of glucose. Indeed, that’s what all starches are – very long chains of glucose. Some chains are branched and some are straight. It is the long straight chains that are most likely to resist digestion.

Anyway, here are three common reasons why some starch is RS:

1) Some starch just plain can’t be reached by digestive enzymes during the trip through the intestine; it’s not there long enough for an enzyme to reach it. Happens with whole seeds and wholegrains;

2) the starch is mainly in the form of long straight chains of glucose; enzymes can only break off the end glucose and again they haven’t enough time to get to the middle of the chain eg starch in the banana; and

3) when starch cools after cooking it can form gelatinised starch which outwits the enzymes eg potato salad.

What does it all mean?

Note that all the sources of RS mentioned are whole foods. When a starch gets processed (eg refined flour) it usually takes a beating and starts breaking up. Those long chains become short chains and short chains are dead easy to digest so no starch gets through to the large intestine (which annoys the bacteria there, let me tell you. They really look forward to a feed of RS. Bought something on eBay and not arrive? Times that by 100 and that’s how annoyed they get).

There is much more to the story than I can quickly relate. For example, there are three different types of RS and they are involved in more than just bowel health – they probably help control fluctuations in blood glucose making RS a great diabetes buster.

The message, I believe, is that here is another reason to eat mainly minimally processed foods because they offer bio-active compounds and benefits that you can’t simply replicate by heavily processing natural foods, chucking in some nutrients, then trying to pass it off as close to the original.

If I can put it in music terms: this weekend is the five day Elvis Festival in Parkes, New South Wales where highly processed Elvis impersonators number more than the residents. It is great fun, but for the rest of the year you want to listen the unprocessed original.

Vitamin D

2011-12-15T21:28:00.000-08:00

Last month I was very lucky to be the minder for Michael Holick, professor of medicine from Boston University during his seminar series on vitamin D in Sydney and Melbourne, Australia. Want to learn fast? Book a professor for four days. They are very clever people.

Every cell has a vitamin D receptor

Michael is a world expert on vitamin D. Just to remind you how young the science of nutrition really is, know this: he discovered the circulating form of vitamin D as a Masters student. This is the same form that is measured when you have a blood test for your vitamin D status.

In my youth way back I took cod liver oil by teaspoon to avoid rickets. Will never forget the taste. Now, vitamin D has gone beyond bendy bones. Nearly every cell in your body has a vitamin D receptor. Over 2000 genes are influenced by vitamin D. No surprise that a lack of D has been linked to major conditions from Multiple Sclerosis, heart disease, bowel cancer and breast cancer to diabetes, the flu and depression.

Kellie Bilinski, an Australian breast cancer researcher told me that D regulates about 200 genes in breast cancer cell production and low D was directly related to a higher risk of breast cancer.

Is there a vitamin D problem in Australia?

Yes, for two main reasons. First we have been discouraged to expose our skin to sun during the daylight hours when our skin makes vitamin D in response to the UV rays, mainly due to the realistic fear that we may get skin cancer. The avoidance of the sun by mothers and infants has seen the re-emergence of rickets in Australia.

Secondly, for many there is little opportunity to venture outside during working hours. Three out of 10 healthy Sydney office workers have low vitamin D in the summer. They couldn’t even boost their vitamin D over the weekends. Three in four healthy dark-skinned Australians are D deficient in the winter (I might add, that is common around the world. Michael Holick had just been to India where D deficiency is rife).

I have specified “healthy” people because we assume they can get outside of their own choosing. There are much higher levels of D deficiency in the elderly and unwell. Around three quarters of hospital inpatients are D deficient.

For every 10 nmol/L (25 ng/mL) our D levels rise, there is a 6-8% reduced risk of early death, possibly due to a reduced chance of cancer.

What does it all mean?

First, get your vitamin D levels checked. They will be lowest in September and highest in March in the southern hemisphere; vice versa in Europe and North America. Although there is debate as to the “healthy” blood level of D, every expert is saying you should have at least 50 nmol/L (125 ng/mL), although Michael Holick believes you are better off at 75 nmol/L (187 ng/mL). If we use the latter figure then Dr Rob Daly from Deakin University says that 73% of Australian don’t make the grade.

You will only reach healthy levels of D by getting a judicious exposure to sunlight or taking supplements of 50 mcg (2000 International Units) of vitamin D.

It is very difficult to get enough vitamin D from food alone. Most researchers now agree that you will need to eat 15 mcg (600 IU) a day. With table margarine providing 1 mcg per two teaspoons, oily fish 2 mcg per 100g, D-fortified milk with 1-4 mcg per glass you can see it will be tricky getting your 15 mcg a day. Only one food can provide your daily needs of D in a serve and that is light-exposed mushrooms, but they are only available from some Sydney grocers, although they have been in the US and Canada for a couple of years.

A final thought from Michael Holick. Why did the dinosaurs die 65 million years ago? No brainer. It was vitamin D deficiency caused by the asteroid dust cloud blocking out the sun. Want more? Watch his quick-fire presentation.

The Vegan Diet

2011-12-14T16:49:00.000-08:00

Let me introduce you to Donald B Ardell, from Florida, US, a gentleman with much wisdom, an ardent promoter of wellness and someone who has taught me a lot over the 23 years I have known him, especially through the 673 editions of his [http://www.seekwellness.com/wellness/ardell_wellness_report.htm Ardell Wellness Report]. Don is a four-time world champion triathlete in his age group, which is past the seven decades post.

Recently he became what society labels a vegan, someone who doesn’t eat any animal foods whatsoever. Below is my edited version of what Don wrote recently, followed by my response.

Don Ardell becomes vegan

Thanks to the initiatives of my dear wife Carol, I have studied and followed a plant-based diet. This way of eating is much more disciplined, focused and restrictive than my usual pretty sensible food pattern that was basically aligned with U.S. Dietary Guidelines. I did not, until recently, see any reason to change my diet pattern, which complemented a lifelong vigorous exercise routine. Prior to the recent change, I ate small portions of lean meats and lots of seafood, along with plentiful fruits and vegetables and only a moderate amount of sweets and fats. I avoided the deadly stuff.

While I'm fond and respectful of animals and supportive of living lightly on earth, I have not carried such good intentions to the level of role model in practice. Sure, I was all for environmental sensitivity, but not to the point of becoming an actual vegetarian, let alone going as far as this new plant-based vegan regimen. I enjoyed fish and lean meat dishes, now and then. But, until I got involved in this plant-based situation, I've been more talk, less action. I put aside thinking too much about unpleasant realities, particularly the nature of modern mass harvesting of sea life, the cruelty of slaughterhouse practices, and the chemicals in play that support production speed and shelf life of animal products.

My dietary habits took the dramatic new turn I've been describing one day while I was in Burlington, Vermont for the national triathlon championships, staying at the home of my friend Judd Allen, eating feasts of barbecued chicken breasts one night and all-you-can-eat whole lobsters the next. Carol, who stayed home, was watching a television program about the transformation of the appearance and health of former president Bill Clinton.

Mr. Clinton, if you have not noticed, is today a lean mean machine, fit and free of the heart problems that plagued him during most of his pudgy, out-of-control years in office. (That last sentence was a reference only to his diet.) The former president has become a born again, plant-eating enthusiast, describing the nature and touting the benefits of his new vegan diet. (Though he does, like yours truly, occasionally depart from perfection by tasting of the forbidden non-fruits every so often.)

Mr. Clinton makes frequent reference to the influence of Dr. Esselstyn and his colleagues Dr. T. Colin Campbell, author of the bestseller, [http://www.thechinastudy.com/about.html The China Study] and to Dean Ornish in California, who also has written books about a plant-based approach to [http://www.amazon.com/Ornishs-Program-Reversing-Heart-Disease/dp/0804110387 heart disease avoidance and reversal]. All three were key figures who inspired Mr. Clinton's diet reforms. The former president claims he now lives on beans, legumes, vegetables and fruits. He abstains from all dairy products. He claims the diet has changed his metabolism and accounts for his 24-pound (11 kg) weight loss, which is about what he weighed in high school.

In the CNN interview with Wolf Blitzer, Mr. Clinton said his concern over a worsening heart condition led to radical changes in his eating habits. He did the research and learned that 82% of people since 1986 who followed a plant-based, no dairy, no meat of any kind diet healed themselves. Their arterial blockage cleared and calcium deposits around their hearts broke up. As noted, this interview was fateful for me because my wife was watching. Then she did additional research on her own and, when I returned home from Burlington, I discovered my diet had changed, as well.

Previously, I had paid little attention to the names for those who followed one kind of plant-based regimen or another. I thought vegan was a Star War character - now I am fast becoming one - and I realize it has little to do with science fiction. Actually, the Esselstyn approach is even more ambitious that simple vegetarianism or veganism (if that's even a word): the Esselstyn plan also eliminates oils, dairy and takes aim at a few other things as well, such as caffeinated coffee. I still miss seafood, but less now than in the beginning of this experiment! No, I have not yet given up REAL coffee.

After reading about and practicing this approach for a few months, Carol and I had occasion last week to travel to Orlando to attend a lecture by Dr. Esselstyn at the University of Central Florida College of Medicine in Orlando. The good doctor gave a talk, well supported

with illustrations that made it easy to comprehend the technicalities of how the plant-based approach reverses heart disease and, best of all, prevents it in the first place. He is an excellent speaker and a charming, knowledgeable and likable person. My only concern was that he looked way too skinny. If I ever start looking that gaunt, I'm going to make my way to the nearest McDonald's.

Thanks to recipes in plant-based cookbooks such as __Forks Over Knives__, the meals served up by Carol have been delicious. I do not feel deprived in any way. I'm not going to exaggerate or get carried away, but I must confess that I am no doubt more beautiful and virtuous than ever because of this diet. In addition, I'm younger, stronger and faster, have higher morale, superior bowel movement and no doubt more antibodies for resisting diseases and Republican presidential candidates. In addition, I'm basically tax exempt and I've been getting better gas mileage.

**Glenn’s response**

Don, I admire anyone who can change their eating habits. Most adults can't or won't. Be proud that you have the will to do so and then be grateful that you are fortunate enough to do so. This is a planet where broad estimates are that 1-2 billion struggle to get enough calories and 2 billion abuse the freedom from starvation by over-consuming calories. Many of the latter will get a health benefit from choosing your style of eating. A plant based diet is more gentle on the planet than is a burger-centric diet.

I am not a vegan, nor likely ever to be. From family history and having had my mitochondrial DNA analysed I have a southern European background where there was a clear survival advantage from consuming dairy foods. I enjoy low-fat milk and yogurt, as well as experiencing cheeses from around the world. Humans have eaten eggs for eons. They are a great source of lutein for protection from macular degeneration, and nothing is easier than an egg for a quick nutritious meal - omelette, frittata etc.

All wise people seem to be in agreement that humans evolved as seafood and meat-eating animals. Early humans were never too far from the sea, estuary or river. There has been a strong argument that cooking gave our brain evolution a kick-start so we would become clever and devise easier and more efficient ways of doing things (we've over-stepped the mark on efficiency now, making slobbishness the default position of many).

Considering the diet that allowed humans to prosper as a species, and blending that with both nutrition and an acknowledgement that we will have 9 billion mouths in 2050, I believe the flexitarian diet to be the best for affluent nations. Simply put, for my 21 meals a week, 16 are vegetarian (including dairy and eggs), 2 seafood, 2 chicken, 1 meat, allowing for natural weekly variation. All snacks are vegetarian.

My version of flexitarianism also respects the eating style of others, so I will eat any meal offered to me by friends or relatives. I have lived with a family in Spain and will soon live with a family in Buenos Aires. There I will eat what they eat. This choice is made easier as I don't have any food allergies or intolerances. Will you now get fewer dinner invitations Don?

I say to you, with love and respect naturally, that your previous diet is likely to be a better choice. Once you have ticked off 70 birthdays your gut's ability to absorb vitamin B12 is diminished and a vegan diet is low in B12, as well as being low in iron, zinc and calcium, all essential minerals for long term health. It is believed that vegans need 150% of the recommended dietary needs of iron because iron is less bioavailable from plant sources when compared to animal foods. Sure, you can take supplements to make up the difference, but I suspect that won't suit your thinking.

As always Don, it is your choice, and one of the greatest freedoms in life is to have a choice.

Glenn’s response

As always Don, it is your choice, and one of the greatest freedoms in life is to have a choice.

Overweight: is there a population solution?

2011-11-20T14:45:00.000-08:00

First, let me be bold and honest. The answer to the question is “No”. Not while we live in an affluent democracy with abundant, relatively cheap food. You may have your own idea for a solution. Certainly there have been many espoused – tax cakes, confectionery and soft drinks, tax fat people, ban advertising of foods you perceive to be evil or just plain ban every processed food. Simple. It seems that we favour controlling the environment to educating and encouraging people to eat intelligently. The public weight loss campaign is a favourite solution offered by governments.

Does anyone listen & act?

Obesity Reviews published a paper that considered 60 interventions or policy proposals since 1980. Although presumed to be useful, may public campaigns have uncertain benefits and, indeed, many aren’t even evaluated for effectiveness. The [http://www.drawthelinewa.com.au/ last Australian campaign] showed 55% awareness among adults. So what? I’m aware of many things too but do stuff-all about it. I know I should turn off appliances and not always have them on standby like I do. I know Mugabe is not good for Zimbabwe but haven’t got around to assassinating him. Evaluating awareness and asking people questions about their intentions is irrelevant to success or failure.

The review also suggests that there can be unintentional consequences, such as some adopting unhealthy diet practices to achieve a goal weight. The Singaporean Trim and Fit program was criticised because it might contribute to eating disorders.

Stigmatised sub-class

Being fat is stigmatised, linked to stereotypes of stupidity, ugliness, weakness and laziness. I would imagine that every campaign directed at their weight can’t make them feel better about themselves. In 2008 it was reported that the US state of Mississippi planned to [http://www.telegraph.co.uk/news/worldnews/1577463/Ban-restaurants-from-serving-obese-people.html ban fat people from restaurants], presumably to keep them away from temptation. Bet that would have been helpful. Is this form of discrimination healthy? Should we fire health professionals, airline staff, police or firemen once they are judged to be fat? For some, I would say “Yes”. A 140kg fireman may be a risk to himself. Yet an overweight dietitian may be a more credible voice about healthy eating than one that can barely throw a shadow.

The review argues that public campaigns focus solely on the kilojoule and health benefits of foods and completely forget the social context of food. If you are told to cut out cheese and wine would you be welcome at your grandparents who left Italy in the 1950s to start life in your country? I now refuse to do media interviews about what to eat over Christmas. Hey, no-one listened in the 1980s, the 90s and frankly I no longer care what you eat for Christmas. Overindulge like most do, enjoy it and do some activity to balance things out.

Responsibility

Although I feel that it is my responsibility, and mine alone, to look after my weight and health, not everyone has that capability. If you are unemployed, have a lousy job, live in a threatening household, hospitalised with a severe injury, feel alienated, or can’t speak the local language then I suspect that looking lean may not be a priority; may not even be on the first two pages of your priority list. I doubt if a weight loss campaign offers them anything more than guilt.

Public weight campaigns have a shot-gun strategy – send out a few messages and hope some will stick. That makes them ineffective. The last Australian public weight loss campaign cost you $45 million, a lot of it on commercial TV. There has to be a better use of the money. That campaign is being written up for a science publication. Hopefully the data will prove me wrong.

It has been suggested that we reward “good behaviour” and give bonuses for weight loss such as the police in one Mexican city who received 100 pesos bonus for every kilo they lost. How would you feel if you were a lean local and heard about that? I would gain a kilo in December, lose it in January, gain it back in February, on and on. Nice little earner. Healthy?

What does it all mean?

Frankly, I think you can have any viewpoint on a population solution to overweight, and justify it however you want, but you would be hard-pressed to show that it was effective, and by that I mean effective in permanently changing eating or activity habits to create weight loss in more than, say, 2% of the population over a five year span.

I’d love to see the stairs full of people and the escalator used by only those over 90, parents carting young children or those recovering from a sports injury. I would also love to see people encouraged to eat well for their health, well-being and longevity while never once mentioning their weight. Public health campaigns should be about health, fitness and well-being. Forget weight – too difficult, too dangerous and nobody listens.

Reference: Obesity Reviews 2011; 12: 669-679

Colon Cleansing

2011-10-27T17:39:00.000-07:00

We are fascinated by our bowels. Indeed, they dictate so much. If they work as they should, the world is perfect. If they start creating havoc, it is best to stay at home. A normal functioning intestinal system should be appreciated. It has taken a great-tasting meal, liquefied it, mixed it with enzymes, then gently extracted nutrients and bio-active compounds that nourish us and complement our immune system to keep evil bugs at bay. The fibre does an excellent job of protecting the bowel lining for year on year.

I suspect that as the end result doesn’t look pleasant or smell like perfume there is an assumption that there is a problem. Food does not rot or decompose within you. The colon is not a toxic waste dump. It is a brilliantly designed waste disposal system. Even diarrhea is good for you; it is usually a rapid expulsion of pathogenic bacteria (think food poisoning). It doesn’t feel good at the time, but diarrhea will often save your life. Vomiting is good for the same reason.

Long history

The concept of colon cleansing was based on the assumption that disease resided or originated the bowel. Ancient Egyptians and Greeks had the idea that food was decomposing at the back end and clean-out would help. Early in the 20^th century washing out the colon with large volumes of fluid was a popular therapy. Despite our excellent knowledge of digestion, some think that this most strange of activities still offers merit in the 21^st century.

Unpleasant side effects

A review article detailed a couple of cases where colon cleansing (or colonic irrigation) caused medical problems of intestinal pain and diarrhea. Some people receive up to 60 litres of water, with or without herbs, coffee and so-called “natural” ingredients.

The authors point that those likely to request colon cleansing may have medical problems like Crohn’s disease and haemorrhoids, and are more likely to experience adverse effects with this uncomfortable practice. Even if you are reasonably healthy, you can get side effects like nausea, vomiting, diarrhea, dehydration, pancreatitis, bowel perforation and infection from colon cleansing.

What does it all mean?

Of course, sometimes a bowel washout is necessary for medical examinations or surgery such as that for colon cancer. For the rest of us, know that your bowels don’t require some liquid intervention. Apart from the discomfort and there not being a shred of evidence for a health benefit, you will be washing out all those healthy bacteria that produce nutrients for your body and compounds that protect the bowel lining. Your body already has a natural detoxification system – the liver, kidneys, lungs and the intestines detoxify you in perfect harmony while you enjoy life.

Don’t engage in colon cleansing. Other forms of madness are far more healthy, like supporting the Fremantle Dockers football team, wearing ugg boots and eating alone in restuarants.

Reference: Journal of Family Practice 2011; 60 (8): 454-457

Eating alone

2011-10-17T22:28:00.000-07:00

Because I am responsible for some research at the University of Western Sydney, 2-3 times a year I fly 4000 km to Sydney, then catch a train out to Parramatta in the deep western suburbs of the city. On arrival I dump my kit and head down to the sushi bar or Vietnamese restaurant for dinner. I sit there on my lonesome, eat and read (see pic).

I get sad looks and people comment that they hope to never end up like me, you know, kicked out of home, no friends, a person of interest to the local police.

Read, listen, type

Past research suggests that if you eat with friends then you are likely to eat more food, probably because you chat longer, drink more and eating is a social occasion so why not enjoy a second helping or some dessert? How much more? I’ve seen research ranging from 25% more to 100% more.

Research from the 1990s also found that lone diners who read seemed to stay at the meal table for longer. They didn’t record how much was eaten.

A study conducted in South Australia wanted to see if more food was eaten when someone ate alone while reading, listening to an ipod or using a laptop at the table. These people were labeled with the crushing expression “without social interaction”.

30 minutes

The observations were done at McDonalds in Adelaide because a Maccas menu is standardised and it easier to determine how much is eaten than at my sushi bar. Someone secretly watched all diners and recorded 141 people having no social interaction. They couldn’t include drinks because a secret observer can’t tell the difference between diet or regular drinks. The meals chosen by the observed lasted from 2-44 minutes, with half an hour being the average.

Music, typing, books didn’t increase eating

If you read, typed or tuned into your own music then you stayed longer, especially if you read. Thankfully, reading didn’t mean that you ate more. You spent twice as long at the table, but you didn’t eat more. Only one of those 141 diners went back for extra food. The researchers speculated that eating with others stimulated other social eating dimensions encouraging people to eat more; the mere presence of food didn’t drive people to over-eat. Reading while eating may have done no more than to reduce the discomfort of eating alone.

What does it all mean?

If you find yourself eating alone and happy to catch up on emails, tweet, read a novel or chill to some garage rock (my favourite) then ignore the looks of those thinking that you are tomorrow’s front page news. Just choose your meal wisely and enjoy it. It’s unlikely you are going to overdo it.

Every now and again have a look around. That dodgy bloke in the corner with the note pad and the camera stuffed under the jacket could be from the local university. Pop over and tell them that laptopping, ipodding and reading is a form of social interaction; just because I’m not talking doesn’t mean I ain’t interacting with society. Hey, aren’t I interacting with you right now? Hope you’ve enjoyed it as much as I have. Seriously.

Reference: Appetite 2011; 57: 77-79

Chewing gum

2011-09-18T16:37:00.000-07:00

It seems mandatory that every soccer boss chews gum during the match. Maybe it helps to control the nerves. Or maybe it is based on decade-old research suggesting it sharpens the brain.

Chewing gum fits into the “feels good, looks ugly” category. I’ve seen presenters chew gum as they talk, giving the occasional flash of white blob. Kind of distracts from the message they offer.

Teeth, heartburn and your brain

Forget looks. What does the research tell us, because we always love it when someone applies a bit of science to a common pastime?

A small study back in 2005 revealed that chewing gum can ease symptoms of heartburn, probably due to the swallowed saliva buffering stomach acid, and because chewing quickens the emptying of the stomach.

We know that the saliva production stimulated by sugar-free gum chewing helps protect the teeth from decay after a meal. The action of munching away on gum also increases blood flow to the forebrain by 25%. Does that mean that extra glucose is being transported to the frontal cortex, helping memory and thinking? Initially it was thought so.

Thinking & memory

More recently, college undergraduates underwent a series of cognitive tests after they had either chewed gum or had nothing to chew. The gum chewers did better on word recall and speed of mental processing. The greatest advantage in chewing gum for five minutes before the test was in the first 20 minutes or so of testing, after which the test results tended to even up.

Before, not during

The researchers acknowledge that there is other research showing little mental benefit for chewing gum, but this has been in studies where gum was chewed during the tests. In this study, when the gum was chewed and spat out before the tests started, the participants did well; when the gum was chewed during the tests they did no better than the non-chewers.

The authors state: “Clear performance advantages emerge when gum is chewed prior to (but not during) cognitive testing, although the benefits persist only for the first 15-20 minutes of the testing session.”

What does it all mean?

First, please don’t chew gum as you present to an audience. I don’t need to see that bolus circumnavigating your gob. Now, if you have a tricky problem to solve, maybe reaching into the pocket for a sick of gum could help you find a resolution. Just remember to chew for five minutes and then discard the gum into a bin before you face the problem. To help keep your fangs healthy, then it makes sense to choose sugar-free versions of gum.

Recently I was given a sugar-free gum that was impregnated with calcium. If they promise to advertise in my newsletter, I’ll tell you the name. Oh, OK it was Extra Professional with about 40mg calcium per tablet (you need about 1000mg of calcium a day for solid bones). It’s relatively new to Australia and New Zealand, although it could have been around a long time near you.

Reference: Appetite 2011; 57: 321-328

Carbohydrate blockers

2011-08-30T22:30:00.000-07:00

Hi Glenn,

Thank you for your newsletters. I always find your information up to date and interesting, and so relevant to everyday life.

I work in a gym and have a patron whose latest questions are all about products that inhibit the uptake of carbohydrates.

He has asked about white kidney bean extract – “I’m going to use it in my next cutting phase, so I’m wondering what is the best way to use it? Eat white kidney beans? Or buy a supplement/pill?”

He has also asked about the product C-plex 60 which claims to reduce carbohydrate absorption by over 80%.

I am sceptical about these products but the individual seems hell bent on trying to convince me that they are legitimate.

Many thanks,

Georgie Feakes

Thanks for your note Georgie.

Be aware that if someone has a deep belief then nothing you or I will say will make a difference.

Also be aware that anything that causes significant carbohydrate malabsorption will also cause severe gut pain, gas and diarrhea. The gut was designed to digest and absorb food. Stopping that function is unnatural and the body will react in a very uncomfortable fashion. There is no way a product will reduce carbohydrate absorption by 80%. If it did, then you would be in hospital.

Some products may cause a very small amount of carbohydrate malabsorption. There is evidence that the white kidney bean extract you mention does encourage weight loss], in the region of 1kg per month, through inhibiting some carbohydrate digestion. I would argue "Why not eat a little less instead. Cheaper, easier and probably more effective".

Get educated (Perth, Western Australia)

2011-08-30T22:28:00.000-07:00

Once again, for those of you living Perth, Western Australia, I shall be running two different nutrition courses for the University of Western Australia Extension Program. The first is an honest, sometimes quirky, seminar on living for long life. The link for this course is here.

For the first time at the university I shall also be running a very practical course on nutrition for sports performance. There is more here. Whether you are building up to your first 10 km run or if you are a long-course triathlete there will be something here to improve your sports performance.

Love to see your face.

When the gavel falls

2011-08-30T22:23:00.000-07:00

There you are, waiting the decision. You’ve done the crime and you’ve done the time. Now you reckon you should be released from prison so you can start life afresh. The judge reads the report, listens to your arguments for release and makes the decision: you are to remain in prison. Not what you wanted to hear. The judge then calls for a recess and heads off to morning tea.

It is all about timing

What you experienced was probably more a case of bad timing than a poor argument on your part. There is a saying that a decision often “depends upon what the judge had for breakfast.” Research on over a thousand parole decisions agrees. Judges make decisions more likely to favour a prisoner if the judge has just returned from a meal or a break. And the difference is significant.

No chance just before lunch

At the start of the morning or just after a food break, around two thirds of prisoners got a favourable parole decision. By the end of the session, with the judge due for a meal or a break, virtually no prisoners heard the words they wanted to hear. The researchers state: “the percentage of favourable rulings drops gradually from 65% to nearly zero within each decision session and returns abruptly to 65% after a break.”

Food and a rest is the key

Naturally, the researchers looked at other factors that could be playing a role. Did the better class of prisoner come in near the start of a session? No. Did the judges know each case before they appeared and scheduled a break after a couple of tough prisoners? No. The truth is that it was an entirely random process. It all came down to how well fed and refreshed the judge was. How’s that for justice?

What does it all mean?

This research has much broader implications. I used to mark university student assignments. The best I could do was 15 at a time. By the time I got to #12 my brain was beginning to disintegrate. I’m sure the last 3-4 in a marking session got lower marks because my brain was fried. What if you are the last person to be interviewed for a job? Have you got the same chance as the first two?

And then think about what you do during the day. Would you and your thinking benefit from more breaks? Did you eat breakfast? If you did, we know from other research that you will likely be thinking better and making wiser decisions.

And if you ever have to front up to court make sure you take some fruit to offer the judge because if it is coming up to his/her lunch break it could save you a lot of grief.

Reference:

Proceedings of the National Academy of Sciences 2011; 108 (17): 6889-6892

When wine meets your teeth

2011-08-11T21:41:00.000-07:00

You may remember that a couple of issues ago Warwick Boardman asked about the pH of wine. I though I would give you a brief update. You see, Warwick had asked a question I didn’t know the answer to, and that upsets the equilibrium of my brain, so it was off the Medical Library for me.

pH of wine

First, a real quick reminder. It is the low pH levels (high acidity) of soft drinks, fruit juice and sports drinks that is the most likely to cause tooth enamel erosion, not the sugar content. For more, see my blog here.

What about the pH of a social and relaxing glass of wine? I like the commitment of the German researchers who analysed the pH of 50 white wines and 50 red wines (ref 1). They found that they range from 3.0 - 3.9 for white wine and 3.4 – 4.1 for red wine, which makes acidic, although less acidic than soft drinks and fruit juices which have a pH commonly around 2.3 – 3.2.

Just based on those figures you could guess that white wine, generally, had the greater potential to cause tooth enamel erosion. You would be correct. Exposing extracted human teeth to wine found that white wine caused more calcium release from teeth than red wine. Note that this study was done with extracted teeth dropped into a beaker of wine. It did not take into account the buffering effect of saliva or food that might be present in the mouth of a consumer.

Saliva

An Australian study looked at the buffering effect of saliva after drinking wine (ref 2). They found that saliva was “relatively ineffective” at neutralising the acid because the pH in the mouth remained low enough, for long enough, after drinking wine for enamel to start to dissolve. Pity, because I always thought that saliva would be helpful.

Quick tip. Don’t clean your teeth straight after consuming acidic drinks. You might think that helps avoid erosion. It doesn’t. Any micro-damage from the acid will occur quickly. Allow time for your saliva to remineralise your teeth. That’s a critical function of saliva. It’s not just for licking the occasional envelope. Wait, say, for an hour between drinking and brushing your fangs.

Wine tasters

Already you have been thinking: “What about wine tasters?” An enviable occupation, that’s for sure. Some of these folk will be tasting 20 – 100 wines a day, maybe more, and the wine can stay in the mouth for some time. Yes, there have been reported cases of the teeth of wine tasters being affected by wine. One wine taster had tasted at least 20 wines a day for 10 years and had a five year history of tooth sensitivity to hot and cold food (ref 3). A 56 year young lady who drank a bottle of wine a day for 34 years also presented to her dentist with tingly teeth (ref 4). Yep, the acidity of wine can be a problem for frequent wine consumers.

What does it all mean?

Like any drink with a low pH, don’t let wine wash around your teeth for too long. A glass each day is unlikely to be a problem, but if you enjoy half a bottle or more at dinner every day then your teeth (and liver) might complain down the track. The same goes for juice, soft drinks and sports drinks – some OK, but if you drink them in the litres each day, make sure you see your dentist regularly. Or try drinks closer to neutral pH, like water or milk. Old fashioned, I know, but we have been consuming them for centuries with good results.

Right now I’m looking for research funds to determine the pH of reds bottled in the 1960s and 1970s. If you could help out with either funds or the bottles I would be gratefully smashed.

References:

1. Nutrition Research 2009; 29: 558-567

2. Australian Dental Journal 2009; 54: 228-232

3. Australian Dental Journal 1998; 43: 32-34

4. Journal of the American Dental Association 2005; 136: 71-75

The never-ending salt saga

2011-08-11T21:37:00.000-07:00

I am an avid reader of your newsletter, thank you for all your efforts, they are much appreciated I’m sure by all who read it.

I am 28 years old, very fit and active, and someone who pays much attention to things I eat (apart from the usual chocolate and cakes now and then). I limit my saturated fat intake, and although I’m vegetarian, I eat more than enough protein from dairy, soy and legumes. The only thing that I don't concern myself with is sodium. But then again my blood pressure has never been a problem - always 110-120 / 70-80. Is this a mistake on my part?

So I guess my central question is this - does the research suggest that high levels of sodium cause high blood pressure or is it the case that reducing your sodium intake when you already have high blood pressure helps on reducing it? Or as logicians would ask: Does A cause B or does notA cause notB?

As far as I was aware, salt and hypertension were intimately connected, but in recent weeks I have been hearing contrary study results. Then today I was reading this interview, and this one, both from Scientific American, and things confused me even more.

Would love to hear your take on things. Thanks for this,

Farid

No simple matter Farid. In one of your articles, Marion Nestle's comments have been echoed by many. If you get people to reduce their salt by 10-20% you may not see any effect on blood pressure. Some people may need to reduce their salt intake by 50-80% to have an effect on blood pressure. That is difficult because most salt is added by food manufacturers and salty food doesn't often taste salty, such as bread & cornflakes. Hunter-gatherers ate about 200 mg of salt each day; westerners eat 3000-6000 mg a day, that is, about 15x - 30x as much as we were designed to consume.

Also remember that a high salt diet increases calcium losses via urine, so even if you cut back on salt and there is no effect on blood pressure, it is still good for your bones.

Anyway, there will always be debate. Why are there no clear-cut answers?

1. Because, in nutrition, you can't increase/decrease a nutrient/component in food/diet without changing many other things in a free-living human. Eating less salt is likely to mean eating more fresh foods, such as fruit and vegetables. Is any response due to less salt or more vegetables?

2. We all have differing genetic backgrounds.

3. We all respond differently to our environment, including the food we eat.

I wish I could provide a simple answer. I can't. Just reading the articles you have found will give you some insight as to lack of agreement, one key reason is because we can't find westerners on a truly low salt diet to compare with those on a high salt diet, so we may just be comparing those with a very high salt intake to those with a high salt intake.

The August 2011 edition of GI News also discusses the influence of food and lifestyle on our blood pressure. Scroll down about two-thirds for the article by Alan Barclay.

My view? Keep doing what you are doing. Eat well. Don't add salt to food. Choose lower salt varieties of commercial foods. No harm. It may be better for you, who knows?

Onion myth

2011-07-24T18:02:00.000-07:00

I’ve been attached to the internet for 16 years. Still fondly remember the first desktop modem and its dial up sound. Since that first modem I have never received an unsolicited nutrition/food based email that made any sense. I’ve been told that Diet Coke rots the stomach, that I should never eat bread with fruit because it confuses the digestive enzymes and that margarine is a molecule away from plastic, which makes as much sense as wine being a molecule away from that nice steak you are having with it. And now one about onions and the flu.

The onion email hoax

Apparently when the flu epidemic hit the world after the WW1 a doctor asked a farmer why his family didn’t get the flu when many around did. He believed the solution had been an onion placed in a dish in every room. The doctor supposedly placed the onion under a microscope and discovered it had “absorbed the bacteria, therefore, keeping the family healthy.”

Hold up there! The flu is a virus, so what’s this about absorbing bacteria? Virus. Bacteria. Very, very different. And did I read the onion went under a microscope? Well you are only likely to see a virus under a scanning electron microscope and you couldn’t get hold of one of those until 1965. Sadly, many can’t sense a hoax when it smacks them in the face. If you have time to burn then you can read the email on the snopes.com site http://www.snopes.com/medical/swineflu/onion.asp.

Onion and food poisoning

Some of the onion email hoaxes go on to claim that the onion is one of the highest risk food-poisoning foods around. Why? Because the onion is a bacteria magnet, remember, stopping you getting the flu caused by a virus! They say the onion is not safe even in a zip-lock bag in the fridge. Apparently, cookbook author Zola Gorgon wrote the original story about onions being a common cause of food poisoning. Now, don’t bother looking for cookbooks by Zola Gorgon, just think about her name for a moment. Zola Gorgon.

Raw onions safe

Food safety expert Dr Ben Chapman from North Carolina State University says there haven’t been any recorded food poisoning outbreaks due to raw onions. Not one. He says that onions are not a food that supports pathogenic growth, well, not raw ones.

What does it all mean?

Remember, scary food/nutrient/nutrition emails have a 100% record of being wrong. Just look for the “forward this to everyone you love” at the bottom of the email. It is code for “hoax”.

It is exasperating to educate the public if there are huge sections who lap up a good story, and not for a second ask themselves if the story is plausible. Why don’t we get government programs urging us to leave an onion in a dish as we come into winter? Why isn’t there a Ministry of Onion if it is the best thing for flu avoidance?

What’s the best evidence that someone just made this stuff up for a joke? You probably got it. The cookbook author, Zola Gorgon. Well done. If she existed and was an author she would be listed as Gorgon, Zola. Now you must get it. All a bit cheesey and on the nose. Why don’t you make up a ridiculous food story and send it around and see how quick you get onto snopes.com? And don’t forget to give yourself a silly name.

Zinc and the common cold

2011-07-24T17:56:00.000-07:00

We have previously discussed that vitamin C is not a useful supplement for lowering the risk of the [http://glenn-glenncardwell.blogspot.com/2011/01/vitamin-c.html common cold]. Our good friends at the Cochrane Database has crunched the science behind what might be a useful adjunct to scare away the common cold virus far better than an onion. The answer is zinc, but you have to get in early.

Zinc taken as a lozenge or syrup within 24 hours of cold symptoms being detected reduced both the severity and duration of the cold in otherwise healthy people. The zinc supplement will need to be taken for at least five days. For some, taking zinc can create side-effects of nausea, especially with the lozenges.

The problem is that no-one is really sure what is the effective dose of zinc. We need between 8mg (women) and 14mg (men) of zinc each day. The Nutrient Reference Values recommend that we don’t consume more than 40mg of zinc a day. There is also evidence that vitamin D, often low in winter, also helps keep the common cold at bay. Maybe, just maybe, D + Zinc could help you sail through your next cold.

Reference:

Singh M, Das RR. Zinc for the common cold. Cochrane Database of Systemic Reviews 2011, Issue 2 (just put this info into your search engine and you will easily find this free downloadable pdf).

Sugar - evil for 40 years

2011-07-04T20:13:00.000-07:00

It is nearly forty years since John Yudkin wrote the book Pure, White and Deadly. He thought there was a direct link between sugar consumption and heart disease, since disproven. Are we now eating more sugar than ever or are we eating the same amount as in 1980? Is there a link between our sugar consumption and obesity? Wise people at the University of Sydney have given this some thought.

Sugar consumption, up or down?

Surprising to many who had made assumptions about our sugar consumption, we are eating less than 30 years ago. Yep, less. Hang on, before we go any further, what are we talking about? Sugar is not singular, it is plural. Common sugars include fructose, glucose (also called dextrose), galactose, lactose (glucose joined to galactose), sucrose (fructose joined to glucose), and maltose (two glucose molecules joined together).

Add sugar to your coffee and you are adding sucrose; eat a bowl of yogurt and you are eating lactose, and possibly some added sucrose if it was flavoured yogurt; eat a banana and you get a flavoursome mix of glucose, fructose and sucrose.

What sugar?

So what sugar are we talking about? The Uni of Sydney found that we are eating less sucrose, also known as table sugar or cane sugar, in the last 30 years. More specifically, Australia, the UK and the US are eating less sucrose (23%, 10% and 20% less respectively). If you included all sugars used for sweetening then Australia is eating 16% less sugars (note: plural), the UK 5% less, but the US are chugging down an extra 23% sugars. That is, the US are eating less sugar (sucrose) but more sugars, mainly as high fructose corn syrups.

One thing that contributed to the drop in sugar in Australia was a big switch from regular soft drink (soda) to diet versions. We are drinking less sugar-sweetened drinks, with the decline starting at the beginning of the century, such that one third of soft drinks now are diet drinks. Even the kids have got the message. Fewer children are consuming sugar-sweetened drinks and those that do are drinking a bit less.

Is sugar making us fatter?

Will getting people to consume less sugar make a dent in the number of overweight? The answer seems to be “No” on a population basis. Australians and the British eat less sugar and gain more fat. The answer might be “Yes” on an individual basis. It is not just soft drink that can add sugar and calories/kJs to the diet, it is the biscuits (cookies), cakes and sweet pastries that add their fair share too. Cutting back on those will reduce sugar, along with fat and sodium.

What does it all mean?

I dare say that most readers don’t have a sugar problem. The occasional sweet food (eg chocolate) and the occasional sweet drink (eg fruit juice, soft drink) is not going to bring you unstuck. As we consume less sugar, we still become plumper as a nation, so getting Australians and the Brits to cut back further on sugar may not make a big difference to obesity levels. The US, on the other hand, mmmm, maybe Michelle Obama has it on her list.

What you are more likely to have is a sodium problem. Most of you will eat more than you need and possibly venture into the unhealthy levels (especially if you enjoy cheese, olives, sauces, bread, spreads, breakfast cereals). We still have a population stuck in the 1970s worrying about a bit of sugar and not having a clue where their sodium comes from.

Enough on that. I’m off for a lovely Tasmanian camembert on wholegrain toast. Hey, I’ve told you before, I ain’t perfect!

Reference:

Nutrients 2011; 3: 491-504 (you can download it free from here if you fancy )

pH of wine & beer

2011-07-04T20:11:00.000-07:00

Hi, Glenn.

It's a bummer about fizzy drinks being acidic. I always drink through a straw when available. However, I don't drink beer through a straw – yet. It is possibly more acidic given it probably has higher carbon dioxide content than soft drinks. Perhaps these drinks should not just have nutrition labeling but also an acid rating! Should we wait for these drinks to go flat?

Regards,

Warwick Boardman

A good thought Warwick. Maybe we should put the pH level on drinks. As we have discussed before, the acid content of soft drinks, sports drinks and fruit juices is high and can cause tooth enamel erosion.

As far as I can gather wine has a pH around 3.0-3.5 and beer has a pH of about 4, both in the acid range, although not as acidic as fruit juice, soft drinks and sports drinks, which tend to have a pH of 2-3. There have been reported cases of wine tasters, wine makers and even wine lovers suffering marked dental erosion due to the low pH of wine. To reduce wine contact with the teeth, and to stimulate saliva flow (saliva buffers the acid), drink wine with a meal.

Oh, and Warwick, never let your beer go flat! That is plain unnatural.

To Snack or Meal?

2011-06-27T18:45:00.000-07:00

They say there was a time last century when we used to eat three meals a day and we should have been thankful for that many because kids were starving in Africa. I suspect they were talking about working adults between 1901 – 1970. I doubt whether kids, teenagers or housewives would have existed on three meals only. If they could sneak a biscuit, leftovers or some bread and dripping they would have gone for it.

Snacking & weight & diabetes

Today, for most readers, food is abundant and affordable and available 24 hours a day. That has led to the question from reader Ken Lynn regarding whether it is better for our weight and health to snack through the day or go back to the three meals a day like grandpa did.

A review by nutrition experts in Australia has looked at the research on snacking and health. There was no clear indication whether snacking had any long-term influence on body weight.

It has been theorised that snacking helps control the appetite and reduce hunger. Nice theory, no evidence. Others have suggested that snacking may cause over-eating, but most studies suggest we compensate to balance the kilojoules in the long-term whether we meal or snack. In other words, we tend to over-eat but snacking doesn’t seem to be the cause.

Snacking doesn’t appear to increase your chances of getting diabetes, nor did it seem to help control blood glucose if you had diabetes.

Snacking & the heart

On the other hand, people who snack and maintain their weight seem to have lower blood lipids (eg blood cholesterol and triglycerides). This link has been known for two decades or more, but we are reminded that these studies haven’t gone for longer than two months, so we don’t know the long-term effects. That’s the consistent problem with human studies of this nature is that they don’t go for long because they are so expensive to run.

Also remember that these types of studies don’t generate profits for a company. For example, if snacking was proven to reduce the chance of a heart attack, it won’t change the nutrition message – if you snack, snack smart on fruit, healthy sandwiches, low-fat, low-salt food bars etc. You see, no quick profit for anyone there because the message is the same.

So what is a snack?

Inherent in many eating research studies is that there is no definition of a snack. That cheese and salad sandwich may be a snack to you, a nibble to an elite athlete, but it might be a meal for grandma. You may recall that I discussed the confusion of snacks vs meals in an earlier blog.

What does it all mean?

I think it is still fair to say that, no matter when or how frequently you eat, your health and weight depends on what you choose to eat. Whether you __meal it__ or __snack it__ will be dictated by how you feel and what suits you. I breakfast, then snack, then finish the day with a meal. Perfect for me, but maybe not for you. In the US they say that snacking will become the norm.

Ken says he is 65 years and wants to crack 85 years. Well Ken, I reckon with a few smart food choices you can make 99 years. It is wise not to make it to 100 because dopey journos have nothing more original than to ask your secret to longevity.

If I ever make it that far my answer would be: “Secret to longevity? Air. Keep alternating an inhalation with an exhalation. Now get lost while I eat my cake.”

Reference: Nutrition & Dietetics 2011; 68: 60-64

GI & Rice

2011-06-27T18:43:00.000-07:00

Hi Glenn,

I was wondering if you may be able to help me with a question that a few people have asked me and I am just not sure of the correct answer. I see many young women with polycystic ovarian syndrome who are often pre-diabetic or have diabetes. I encourage my clients and friends to eat a low GI diet and especially when it comes to rice I advise against eating rice such as Jasmine and white rice except for Basmati or Doongara rice.

Last week a friend said to me: "I was raised in an Asian family and our culture has survived just fine for centuries eating this rice and we still do and we are fine even though we eat it a few times every day". He went on to ask me why if they were not obese and didn't have diabetes why we recommend avoiding such rices.

I was wondering if you would mind sharing your thoughts with me on this question. With thanks in anticipation.

Warm regards,

Ginette

Yes Ginette, having asked many folk of Asian background, they much prefer regular white rice rather than brown rice or a low GI rice and have eaten white rice for eons. A traditional white rice based diet also came with vegetables, a little meat, fruit, plenty of activity and a lean body. Under those circumstances they didn't need a low GI rice as the GI of the meal would have been lowered by the vegetables and meat they ate with the rice.

When you add loads of fat, cake, biscuits etc and little activity, very soon you gain weight and it becomes difficult to control blood glucose.

Similarly, there would be little harm in having full cream milk (regarding the fat content), if the rest of your diet was minimally processed, low fat foods. Now, it seems prudent to encourage people to have lower fat milk because they still want a biscuit with their cuppa. It's all about the total diet, more than a single food.

Today we have to give advice about single foods because humans are prone to just eating whatever they like, not what they need. And we find it so much easier to fret about a single food (Diet Coke, dollop of double cream or coffee) than to get a food in the context of a week of eating, or even a single meal.

Coconut Water

2011-06-12T17:49:00.000-07:00

As kids we would get whole coconuts from the shop, hammer a hole in two places with a tent peg, pour the water into a glass and drink some before we hammered the coconut to split it open so we could feast on the white flesh. All very exotic in the 1960s.

Now coconut water has gained public interest as a refreshment, especially with the allure of being a natural drink, not a concocted soft drink. Some have even suggested that coconut water has special properties and would make a good sports drink substitute.

Tropical fruit

Coconut water is the water from within the cavity of a coconut, and is not to be confused with coconut milk made from coconut flesh or the coconut oil used in food manufacture. People in tropical countries have enjoyed coconut water for centuries and it is the water of the young coconut that is prized the most, partly because it is sweeter, having a much higher fructose content. Coconuts are grown in about 90 tropical countries.

Potassium and sugars primary nutrients

You can see from the table below that coconut water has a very small amount of protein, virtually no fat, and a modest amount of carbohydrate in the form of sugars. It will quickly empty from the stomach and be absorbed readily by the small intestine. It is low in sodium and a good source of potassium, just like you would find in fruit juice. The sodium content is higher when the water is taken fresh direct from the coconut, around 30-100 mg in 100 mL.

I have compared the information with that of a popular brand in Australia. You can see that Cocobella is sweetened with sugar and pineapple juice because, like when I was a kid, the taste of coconut water wasn’t a winner. Then again, by the time a coconut reached outback South Australia in 1968, it wasn’t likely to be fresh. (Note: Divide kJ by 4.2 to get Cals).

Table. Coconut water per 100 mLs

Is it a health drink? A sports drink?**

Because it is low in sodium it isn’t similar to a sports drink, which has a modest amount of sodium to assist water absorption and retention in sport. Yet coconut water is very well suited as a regular drink with about half the sugar found in soft drinks. One small study indicated that coconut water was a good post-exercise rehydration drink, although it was rated as being less enjoyable than a sports drink. If you are doing plenty of exercise then the sports drink beats coconut water, but if you are looking for a lower kilojoule refreshment compared to soft drinks then a chilled coconut water could be the answer.

What does it all mean?

I suggest that you be really skeptical of any marketing health claims for coconut water. It does have a small amount of minerals and vitamins, but not really enough to get excited from a nutrition standpoint. Enjoy coconut water as a drink and a way to keep well hydrated during mild sweat loss, just note that it is not a substitute for a sports drink in endurance events. I can’t find a true “pure” coconut water in the supermarket around where I live; you may have more luck in the bigger cities or a health food store.

References:

Medicine & Science in Sports & Exercise 2010; 42: 575

Molecules 2009; 14: 5144-5164

Soft drinks & acid

2011-06-12T17:42:00.000-07:00

Bronwyn Webb wrote to me and said: "I didn’t realise that diet soft drink was bad for my teeth – I always assumed it was the sugar doing the damage and never thought about the acidity".

It's not just you Bronwyn, virtually everyone thinks that the sugar in the soft drink is what is responsible for any tooth problems. Carbohydrate food particles (eg bread, chips and even apple) that lodge between teeth and remain for some time can be eaten by bacteria in the mouth. While munching on the carbohydrate, the bacteria produce an acid that erodes enamel leading to tooth decay.

Drinks containing sugar don’t stay long enough in the mouth for the sugars to be consumed by bacteria. Excessive fruit juice, energy drinks, soft drinks and sports drinks can all cause enamel erosion through acids such as citric acid. Diet soft drink is as acidic as regular soft drink.

So, don't let those kind of drinks wash around inside the mouth. Drinking through a straw can minimise tooth contact with acidic drinks.

Glucosamine & chondroitin

2011-05-10T18:54:00.000-07:00

Come a certain age you begin to take an interest in supplements that aid the memory of car key placement, prevent buttock sag and make joint pain disappear. Glucosamine and chondroitin are meant to help in the latter category, especially regarding osteoarthritis. Both glucosamine and chondroitin are naturally occurring in cartilage and connective tissue in and around joints, so you can see the logic in assuming taking extra as a supplement could help relieve joint pain. Although the argument may be logical, is it physio-logical?

Variation in supplements

There is little agreement about the benefits of glucosamine and chondroitin between researchers, whether for the general public or athletes who give their joints a fair pounding. The consistent problem we have with supplements is that can vary from batch to batch, company to company and they do not have to meet the stringent regulations and proof of efficacy as do medications. Not only aren’t you aware of what you are really getting it also makes it particularly difficult for researchers to both conduct and compare research.

One meta-analysis of six studies involving 1500 people found that there was a delay in the progress of osteoarthritis of the knee after daily use of the supplement for 2-3 years (1). (A meta-analysis is the combination of several studies to get a more precise answer on the effectiveness of a treatment).

Looks good on paper

The authors warn that the results of the meta-analysis should be treated with caution. One reason is because six studies is not enough research on which to base a firm decision. Another reason is that the studies used pharmaceutical, prescription only, products with measured amounts of glucosamine sulphate (1500mg) and condroitin sulphate (800mg). Once other studies with over-the-counter supplements were included in the mix it became very difficult to see either glucosamine or chondroitin having on an influence on joint structure or pain.

Collagen hydrolysate

Be assured that scientists are looking for a natural supplement that will reduce any pain associated with, or the risk of, arthritis as everyone wants to remain mobile throughout life. One such supplement could be collagen hydrolysate. A study of nearly 100 athletes taking 10g of collagen hydrolysate daily for 24 weeks (2) found they experienced much less joint pain. As you know, one study doesn’t provide proof, but it could be one of the new products in the future that extends your knee, hip and athletic lifespan.

What does it all mean?

It’s your call on glucosamine and chondroitin. If you are a believer, continue believing. If you prefer definitive proof (and it may never come) then keep your wallet closed. In the last 12 months there have been three reviews or meta-analysis’ that I know of and they all come to the same conclusion – over-the-counter supplements of glucosamine and chondroitin offer little benefit to your joints (2, 3, 4).

A review by the University of Utah, on glucosamine and chondroitin concluded: “The best current evidence suggests that the effect of these supplements, alone or in combination, on osteoarthritis pain, function and radiographic change is marginal at best. Some patients take these supplements due to a perceived benefit that could represent placebo response, variable absorption, or actual differences in preparations.” (3)

They do acknowledge that there are no safety issues with the supplements, but warn that people taking warfarin (blood thinner) should get approval from their physician before taking either glucosamine or chondroitin.

References:

(1) Rheumatology International 2010; 30: 357-363

(2) Current Medical Research & Opinion 2008; 24: 1485-1496

(3) Rheumatic Disease Clinics North America 2011; 37: 103-118

(4) British Medical Journal 2010 doi: 10.1136/bmj.c4675

Your teeth and acid

2011-05-10T18:52:00.000-07:00

Why might a dentist be the first to diagnose the eating disorder bulimia? Because people with bulimia frequently vomit up their meals on the sly and the stomach acid in the mouth begins to erode the tooth enamel, most commonly on the inside of the bottom front teeth. This is very obvious to a dentist taking a squizz in the mouth.

The same effect can be seen with those who drink a lot of soft drink (regular and diet), energy drinks and sports drinks because these drinks have a pH of 2, still acidic enough to erode tooth enamel. Drinking through a straw will help minimise drink-tooth contact. Tingly teeth? See your dentist for an enamel assessment.

Acid food, alkaline food

2011-04-26T18:08:00.000-07:00

Should you be eating acid or alkaline foods? Let's see if I can make sense of this. We are oxygen breathing, carbon-based, mildly alkaline life forms. The pH of plasma is 7.35-7.45 and the pH inside our cells is 7.1. If they change much from these levels you will end up in hospital. The body has a number of systems to control the pH in your body (eg lungs and kidneys).

Que? What this thing pH?

Mmmm, I knew this would be tricky from the outset. You may have only heard about pH in shampoo ads. Other readers will remember pH from high school chemistry. The pH is a measure of the hydrogen ions in a solution (ie acidity), that is, the number of hydrogens missing their only electron. A pH of 7 is neutral. The higher the pH the more alkaline. The lower the pH the more acidic. As it is a logarithmic scale, every whole number is a 10-fold difference, so a pH of 5 is 10 times more acidic than a pH of 6. Stomach acid, which is hydrochloric acid, has a pH of about 1. That’s why it burns your throat during regurgitation. Still with me?

Kidneys will sort things out

For a century or so we have known that a high meat/protein diet produces excess acid that must be eliminated from the body via your pee. Foods like meat, chicken, fish, eggs and cheese will generate small amounts of sulphuric and phosphoric acid within the body. If you are a vegetarian then you will likely produce excess alkaline, and this will also exit the body through your pee. This is all quite normal and a happy, healthy body will sort all this out while you get on with life. You will not feel a thing.

Tomato is an acid food, right?

You have probably already deduced that we cannot pick an acid food based on taste. Would you have picked meat as an acid food? It is alkaline on the plate, but will leave an acid residue in the body. Is a tomato an acid food? Nope. Most of the natural acids in tomato will become carbon dioxide and water, leaving a residue of a little potassium bicarbonate, which is, da da da daah, alkaline. Tastes acidic, becomes alkaline. Even when you eat pickled onions, they will land in the hydrochloric acid in your stomach and then trickle into the small intestine where it all the vinegar gets neutralised to a pH of 7 by bicarbonate released from the pancreas.

Acid-base diet does have one major health effect

You will still hear clear-headed health professionals talk about the acid-base balance in your body. Nothing to do with the pH of oranges, tomatoes or lemons or whether they sting your tongue. (By the way, tomatoes don’t cause, or exacerbate, arthritis). As mentioned, eating carcasses of meat each day will generate excess acid which will easily be jettisoned in your pee, but, and here is the problem, along with the acid goes a whole pile of calcium. Eat a very high meat diet for a few years and it will be your bones that suffer. We are happy for you to have that steak sandwich, but please add a whack of salad too as plant foods will help you to keep hold of your calcium stores.

This is also the reason that soft drinks have been linked to poor bone health. Drink a vast amount of soft drink, with an acid pH of 2, and the body will have to rid itself of that extra acid, taking some calcium with it. Of course, when you are quaffing 2-3 litres of soft drink each day (that’s 67-100 ounces of soda) then you are probably not featuring milk in your diet and that compounds the calcium problem.

What does it all mean?

In a healthy body, food does not change the pH of the body, thankfully. Wonderful metabolic processes, evolved over millennia, actively keep the pH of your body within a very fine bandwidth. Forget the “acid” v “alkaline” chat and just eat well, you know, the standard “eat fruit and vegetables, go easy on the cookies, trim the fat off the meat blah, blah, blah” you’ve heard a zillion times. With an emphasis on fruits and vegetables, along with an adequate calcium intake and some sunshine, you will also help your body retain its calcium for bone strength. Just another reason to eat your vegies.

References:

Nutrition Action November 2010

Essentials of Human Nutrition 3rd edition 2007; 110-111

Food and gout: a brief update

2011-04-06T17:30:00.000-07:00

Recently I had to review the dietary treatment of gout for a client. Gout is a common form of arthritis, yet there is very little research on the role of food despite textbooks and the web being full of dietary advice and presumptions.

What is gout?

Gout is characterised by high levels of uric acid in the blood (hyperuricaemia), and is more likely to occur in men than in women. The high levels of uric acid can trigger the deposition of sodium urate crystals in joints, causing intense pain.

Uric acid is an end-product compound from the breakdown of purines made within the body and consumed in the diet. Uric acid is normally eliminated via the kidneys so that uric acid stays at normal levels. High levels come from reduced elimination or an increased production. Some medications, such as those for high blood pressure, can also raise uric acid levels.

Gout has long been associated with overweight, binge eating and alcohol consumption. Losing weight and avoiding alcohol is common advice for many people with gout as this reduces the incidence of gout attacks. Beer consumption especially seems to crank up uric acid levels.

Forget common dietary advice

The most common and effective treatment for gout is through medication such as uricosuric drugs that increase the excretion of uric acid in your pee.

There has long been speculation that high purine foods are also a culprit in gout. Cutting out very high purine foods like offal, yeast extracts, sardines and anchovies may have an additional modest benefit with drug therapy, although dietary changes rarely lower serum uric acid by much more than 10%. There is now evidence that most purine-containing food, especially non-animal food, have little effect on uric acid levels.

Today, common food advice is still to avoid foods with modest levels of purine, such as peas, legumes, lentils, spinach, asparagus and mushrooms. It is not clear why spinach, asparagus and mushrooms are mentioned so frequently, as green peas, broccoli and Brussels sprouts have more purine yet I have never seen them mentioned once in a text book (and I have a few) or websites giving advice on gout.

Eat dairy, legumes, veggies and nuts

The truth is that foods such as dairy foods, possibly due to the dairy proteins, nuts. legumes and vegetables, even those with moderate purine content, seem to be protective against gout. A thorough review of the lifestyle evidence on gout risk states that those eating the most vegetables had a 27% reduced risk of gout compared to those eating the least (ie purine-rich vegetables were associated with a lower gout risk). Low fat dairy foods like milk and yogurt also reduce gout risk.

What does it all mean?

Sure, if you eat lots of sardines, offal, and kilos of meat every week then maybe you should cut back. Otherwise, just eat and drink healthy if you have gout. Lose weight if necessary. If you are a boozer, cut back to a maximum of two drinks a day. Cutting out specific purine-containing vegetables will have no benefit at all. In fact, you would be doing yourself a nutritional disservice.

And why is the big toe often the site of the first gout attack? The big toe is at the extremity of the body and generally a wee bit cooler than the rest of your body. Sodium urate crystalises at cooler temperatures. When the pain hits, maybe put on a (second) pair of socks.

References:

Seminars Arthritis & Rheumatism 2008; 37: 243-250

Current Opinions in Rheumatology 2010; 22: 165-172

Public Health Campaigns Dud

2011-03-16T17:22:00.000-07:00

Can you believe it? Thirty years. That’s how long I’ve been encouraging the world to take better care of themselves. Hey you, put some more fruit in your shopping trolley. Jeez Louise, do you really need to be following that crackpot diet? Mate, you are going to travel a lot better if you cut back on the beer and ciggies. The usual advice.

I used to work for a non-government health agency promoting better eating to everyone from school kids to the elderly. Now a report comes out suggesting that I was pretty much wasting my time.

The Cochrane Collaboration has done a review of the risk factor interventions for the primary prevention of heart disease. The risk factors that the programs targeted were high blood cholesterol, too much salt, high blood pressure, overweight, smoking, diabetes, and a sedentary life.

Intervention programs don’t work

They checked out 55 trials that included over 160,000 people running over a period of six months to 12 years (median 12 months). Although there was some small reductions in risk factors, the intervention programs were a dud, having no effect on morbidity and mortality. As I have mentioned in a previous newsletter, any review from the Cochrane Collaboration [http://www.thecochranelibrary.com/view/0/index.html] carries some clout.

Commenting on the report, [http://www.thecochranelibrary.com/details/editorial/983199/Considerable-uncertainty-remains-in-the-evidence-for-primary-prevention-of-cardiovascular-disease-by-Carl-Heneghan.html] Carl Heneghan from Oxford University mentioned that only people with a pre-existing disease such as high blood pressure or diabetes showed much response to intervention, possibly because they take medication and may be more attuned to the severity of the problem. He said that risk factor interventions that try and change behaviour do not work in the long-term.

What does it all mean?

As best as I can gather, the review is saying that the shotgun approach of public health intervention programs, such as telling people to eat less salt and saturated fat, doesn’t really change behaviour. It is only when someone is diagnosed with a major problem that slows them down do they begin to take any notice.

Not that you should trust my observations, but I can tell you in my time in private practice I probably had zero influence on health, although when I worked in Coronary Care in a major hospital I met the single most motivated blokes on the planet. That is, when the grim reaper pokes his head around the curtain, many people are prepared to change their habits. For a while, anyway.

As I write this, my mate Chris Rowley alerts me to yet another public health awareness campaign [http://www.smh.com.au/national/obesity-ads-urge-a-swap-for-health-20110312-1bs1x.html] in Australia. I can’t help thinking that there goes another $41 million down the drain just to keep some public servants occupied. But then, the most unlikely thing to change is human behaviour, whether it is personal or public. (Another observation: the more public weight loss campaigns there are, the fatter we become).

I think our best bet is still to encourage (reward?) the food industry to lower sodium and saturated fat levels, and increase the fibre content, of commercial foods, and just hope that today’s kids become smarter than their parents.

Methane

2011-03-16T17:19:00.000-07:00

In an earlier blog (23 Feb 2011) I mentioned that by eating fibre containing foods you would become a methane producer and therefore, to a mild degree, be contributing to global warming along with the cows.

As commonly happens, I then came across another paper that explained that only one in three people are digestive methane producers (American Journal of Gastroenterology 2010; 105: 1250-1256). Have a look at the person either side of you. One of you is a methane producer.

It also appears that in many cases the production of methane is linked to irritable bowel disease and colon cancer. Abnormal levels of methane could signal that you are unwell, or about to become so. Now, just take a closer look at the person either side of you and hope that one of them looks less healthy than you.

Life is a gas, and it's healthy

2011-02-23T16:29:00.000-08:00

Borborygmi. One of my favourite words. Borborygmi are the gurgling sounds of gas travelling along your intestines. The rumble can be most pronounced during a conversation lull at the dinner table. Hark, I hear borborygmi.

Gas inside your digestive system is normal. It comes from two main sources: 1) the air you swallow during eating or drinking; and 2) gas produced by bacterial fermentation in the large bowel, the back end of your digestive system. Smaller amounts come from CO2 production when your stomach acid is neutralised in the small intestine.

Air swallowing

One obvious way of swallowing air is through aerated drinks such as soft drink, champagne and beer. This usually comes back into the atmosphere via eructation (burping to you). Air can also be swallowed during eating, more commonly in those that eat quickly or talk a lot during the meal. If it isn’t burped out then it will pass from your stomach and into the small intestine.

Bacteria gas

Once the contents of your small intestine pass the appendix and into the large intestine, the resident bacteria feast on the fibre and small amounts of starch and protein that doesn’t get digested. When bacteria feed they produce gas. In fact, 75% of flatus is bacterial gas. As the contents move along the large intestine (aka colon) water is absorbed so the waste becomes more solid and the gas becomes entrapped in large bubbles.

Some bacterial gas is absorbed back into the blood and exhaled. This is the basis of a breath hydrogen test. If you have, say, suspected lactose intolerance your breath is tested for its hydrogen content because if lactose has reached the colon the bacteria will consume the lactose and generate far more hydrogen than normal.

Aroma

Most of flatus is oxygen, nitrogen (the two main components of air), hydrogen, methane and carbon dioxide. Some sulphur containing gases provide the head-jolting aroma. You want to know: why baked beans? The legume family have plenty of fibre and two types of carbohydrate that don’t get digested well – stachyose and raffinose – which then become bacteria food with the end product being gas.

Here’s the physics of what happens to gas down the back end. The abdominal muscles and the anal sphincter contract at the same time, thereby raising the pressure of the gas against the anal sphincter and then, at the magic moment, the pressure gradient sends out the air at high speed through a very narrow slit too small for solid waste to escape. Hopefully. The high speed gas causes the edges of the anus to vibrate. Maybe fart should be pronounced with a distinctive rolled “r”.

What does it all mean?

Gas is normal. You can reduce the amount of swallowed air by avoiding fizzy drinks and eating slower. Colonic gas is from bacteria eating undigested food ie fibre, which is exactly what the health authorities want you to eat. As one author said: “Flatulence rich in bacterial gases might be the price for the large bowel water reabsorption. It seems that little can be done to reduce flatulence.”

So if you eat plenty of fibre-containing food, you will release more methane into the air, vis-à-vis, don’t think you can solely blame global warming on the cows.

References:

Medical Hypotheses 2006; 67: 235-239

American Journal of Gastroenterology 2007; 102: 842-849

Public gas in Malawi

2011-02-23T16:28:00.000-08:00

On the 5^th February 2011 it was reported that public farting will become an offence in the southern African country of Malawi.

“The government has a right to ensure public decency”, said George Chaponda the justice and constitutional affairs minister. “Would you like to see people farting in public anywhere? It was not there during the time of dictatorship because people were afraid of the consequences. Now because of freedom people would like to fart anywhere.”

It’s at this moment you look at the calendar. Nope, 1^st of April nearly two months away. A lost Monty Python skit? Teenage pranksters hacked into Reuters?

Apparently it is a true story (http://www.abc.net.au/news/stories/2011/02/05/3130657.htm) and this fuss is about an amendment to a current law on public farting passed in 1929. This old law says: “Any person who voluntary vitiates the atmosphere in any place as to make it noxious to health of persons in general dwelling or carrying a business in the neighbourhood or passing along a public way, shall be guilty of a misdemeanour.” (vitiate = spoil or impair the quality)

My prediction is that dog ownership will increase in Malawi (you know the rest of the story). And next time your workmate vitiates the atmosphere, remember that it is the aroma of freedom, according to George.

Cuppa tea

2011-02-15T20:41:00.000-08:00

I’m a big fan of black tea due to my English heritage, where you weren’t supposed to leave the breakfast table if there was still tea in the pot. For one of my badges in Cubs I had to prove at the age of seven that I could brew the perfect cup of tea: pre-warm the pot, add x teaspoons of leaves (x = one teaspoon per person + one for the pot), add boiling water, stir, leave to brew for five minutes, pour into cup through tea strainer. Haven’t lost the art.

Why does tea contain caffeine?

It is quite natural for you to assume the caffeine in tea is there just to give you a lift. The tea bush in China was producing caffeine long before humans came by. Its caffeine is to dissuade bugs from nibbling on the leaves. You are drinking a form of pesticide! Don’t worry, all plant foods produce compounds to try and keep the bugs at bay. Some produce compounds to keep humans at bay. For example, chokoes, which are sometimes passed off as edible.

Making your tea leaf

There are different ways to prepare the tea leaf. For black tea, leaves are macerated, allowing the enzyme phenolase within leaf cells to mix with polyphenolic compounds, and left for a few hours to ferment. The leaves are then heated to halt the action of phenolase (enzymes, being proteins, are denatured by heat). Voila! You have black tea, a favourite in the UK, NZ and Australia.

Green tea, an Asian favourite, and white tea (from the youngest bud and two top leaves) are heated before any fermentation occurs. Oolong tea is fermented for only 30 minutes before being heated. All four teas come from the same plant, Camellia sinensis. All four teas have flavonoids, those antioxidant compounds that have created an excited stir in the science world for the last 20 years.

The type and amount of flavonoid polyphenols in tea differ depending on the type of tea and area it is grown. Right now it is impossible to suggest that one type flavonoid had an advantage over another; they probably have multiple positive actions. Thearubigins are the main pigments in black tea. They contribute most of the colour, as well as the astringency and “body”, of the tea.

Caffeine

All four teas also contain caffeine. Love to have a nice bottle of Grange Hermitage for every time someone said to me that they take green tea because they are avoiding caffeine. The caffeine levels of each tea are similar at the leaf level, with white tea being the lowest, around 15mg per brew, because it is usually steeped for a short period. Green tea has around 40mg/cup after three minutes brewing, while a strong cup of black tea may have 60mg of caffeine.

How much caffeine will be present in your cuppa will depend on how long you brew the tea, type of tea, how much tea you brew and possibly even the region the tea was grown (Assam in north east India had the highest leaf level of caffeine in one study).

What does it all mean?

For a long time both tea and coffee unfairly had a bad name, mainly due to their caffeine content. Herbal teas were seen as a “healthy” substitute because they don’t contain caffeine. The consensus is that 300-500 mg of caffeine a day is no threat to healthy adults, although for some even 150 mg of caffeine can disrupt sleep.

Tea is the second most widely consumed drink in the world. No, Coke is not the first, it’s water. Being so popular, tea has attracted a lot of research, some of it showing that tea drinkers have less risk of heart disease, Parkinson’s Disease, type 2 diabetes and even have stronger bones. It is way too early to say that every cuppa will definitely help you to avoid disease, but the comforting thing to me is that nothing suggests that having a few cuppas a day is a problem.

You want to hear a number don’t you? OK, there is broad agreement that up to five cups a day is healthy. Just do what I do – choose big cups.

Reference: Coultate T. Food: The Chemistry of its Components, RSC Publishing 2009

Eating lessons in Kenya

2011-02-15T20:37:00.000-08:00

Recently I popped over to Kenya to be PA for my wife, Toni, who was there as part of a Curtin University delegation. While she worked, I asked Fredie (sic) to show me the real Kenya, not the tourist stuff. We called into a roadside restaurant for nyama chomu, which is salted roast meat, in this case goat. With that we had fried potato balls with tomato sauce, mashed potato with peas and corn and a drink (see photo). They had run out of ugali, a solid corn flour dough, thankfully. I would have been the first mzungu to have been in there for weeks, maybe years, yet it was very relaxing being African.

“So where are the knives and forks Fredie?”

“Use hands.” Stupid mzungu.

“Which hand Fredie?”

“Either. And not like that, grab a handful.”

After eating a modest amount of food, having that constant visitor fear of whether I might regret this meal during the night, I expressed to Fredie that I was done.

“You have to finish the meat. You don’t leave meat in Africa.”

Sawa, sawa. So much to learn.

And I was the only one of the delegation to have polite guts for the fortnight.