Tuesday, December 21, 2010

Vitamin D

Just like there are trends in TV, fashion and music, there are trends in nutrition. If you have been around for a while then you would have seen a few – fat, fibre, calcium, vitamin C, antioxidants, organic, and the favourite of the last five years has been vitamin D. Getting insufficient vitamin D (primarily through too little sun exposure) has been linked to an increase in an ever-expanding list of medical problems such as heart disease, types 1 and 2 diabetes, multiple sclerosis, depression, colon cancer as well as the well-known problem of osteoporosis (brittle bones).

Institute of Medicine report

Three weeks ago the Institute of Medicine released a new report [http://www.iom.edu/Reports/2010/Dietary-Reference-Intakes-for-Calcium-and-Vitamin-D.aspx] on both calcium and vitamin D. The report re-affirmed that too little vitamin D, along with too little calcium, caused osteoporosis.

The report did increase the recommended daily amounts of vitamin D to Americans and Canadians (previously they were the same levels as Australia) and that increase met with support from academics. However, the report was less enthusiastic about the link with lower levels of vitamin D and common medical problems.

How much vitamin D?

Theoretically you can get all your vitamin D through sun exposure, but many are reluctant to do that for fear of skin cancer. Yet, you don’t need much sun exposure – about 5-8 minutes during the middle of the day (approx 10am – 3pm) in summer, and about 30 minutes in winter for light-skinned people living in temperate zones. In other words, not enough sun to burn, or even get red. Otherwise, you need to get from your diet:

19-50 year olds: 5 mcg (200 IU) in Australia/NZ; 15 mcg (600 IU) in US/Canada; it is assumed you will get adequate sunlight in the UK (insert own gag here).

51-70 year olds: 10 mcg (400 IU) in Australia/NZ; 15 mcg (600 IU) in US/Canada; 10 mcg (400 IU) in the UK

71+ year olds: 15 mcg (600 IU) in Australia/NZ; 20 mcg (800 IU) in US/Canada; 10 mcg (400 IU) in the UK

mcg = microgram;

IU = International Units;

1 mcg = 40 IU

Now, the problem here is that it is virtually impossible to get all your vitamin D needs through healthy eating. Our main sources of vitamin D are margarine (1 mcg in 2 teaspoons), oily fish (about 1-3 mcg per 100g), egg yolk (0.5 mcg per egg) and hard cheese (0.3 mcg in 30g). Some milks are fortified with vitamin D (eg Anlene). You can see you will need to scoff quite a bit of salmon, eggs and margarine to get your D needs. (In the US and Canada there are light-exposed mushrooms that provide 15 mcg/600 IU or more in a single serve. I am working with the mushroom industry in Australia to get high vitamin D mushrooms on the market in 2011).

Blood test

One of the most common blood tests requested is for vitamin D, because so many people appear to be low. How low is low? Mmmm. Tricky question. Last century we thought that a blood level of 25 nmol/L (10 ng/mL) was fine because that seemed to stop rickets and osteoporosis. Now experts like Professor Rebecca Mason from Sydney University say that 50 nmol/L (20 ng/mL) is a better goal for overall health. My pathology test form came back stating that a “healthy” level was 75-120 nmol/L (30-48 ng/mL). There is no universal agreement for the ideal blood levels of vitamin D.

What does it all mean?

Those who get very little sunlight, have dark skin, shield their body from sunlight, are in long term care, or are elderly are likely to have low levels of vitamin D. As diet very probably won’t make up the difference in vitamin D, then daily vitamin D supplements of 25-50 mcg (1000-2000 IU) will need to be taken. Get your blood level tested. If it is clearly at the lower level, get some judicious sunlight, eat wisely, and depending upon where you live, track down some vitamin D mushrooms.

Sunday, December 5, 2010

Cramps (mainly in sport)

We have all experienced that excruciating knot of painful involuntary muscle spasm that can stop us dead in your tracks. About two out of three fit and active people have experienced the cramp. It commonly occurs in the calf, thigh or foot. It can happen in both cool and warm environments.

What triggers a cramp?

Nobody knows for sure. Surprisingly, this topic is poorly covered in most sports medicine books and is not well researched. It has long been suspected that the most common causes in athletes are dehydration, heavy salt losses or, more recently, just plain muscle fatigue leading to a loss of muscle control.

Heavy sweating can cause significant sodium (salt) losses from the body, and this may trigger a cramp if the sodium isn’t replaced during the activity. To combat the threat of cramp, athletes add some extra salt to their meals and take a sports drink throughout training and competition. One study of a tennis player who regularly got cramps revealed that he lost more sodium through sweat than he ate in his diet. By taking a sports drink and increasing the sodium in his diet, he was able to reduce the cramps to rare occurrences.

More recently, studies have shown there are no differences in blood sodium levels or levels of hydration in crampers compared to non-crampers leading to the view that cramping is due to a tired muscle losing coordination of its contractions. If low levels of salt in the body are the cause of cramp it does not explain why only certain muscles get cramp or why rest or stretching the afflicted muscle often “cures” the cramp. The best explanation to date is that muscle cramp is due to a tiring muscle losing its ability to control its contractions and going into involuntary spasms.

The best advice we have

The truth is that we don’t fully understand muscle cramp, nor know the best advice to help avoid the cramp. You may have your own solutions that work for your body. Until we know more, the sensible advice is:

1. Drink plenty of fluids during activity to avoid dehydration. A dehydrated body seems to be more prone to cramping.

2. If you lose a lot of sweat during exercise, especially over an hour or more, try a sports drink to help replace the lost sodium.

3. Be fit. Cramps are less common in fit people.

4. Eat well. Cut the saturated fats that clogs arteries. Cramps can occur in muscles that have a reduced blood supply due toas a result of narrowed arteries.

5. Stretch before and after exercise. If you suffer night cramps, stretch before going to bed.

6. Be untrendy and wear loose, comfortable clothes. Tight -fitting clothes can reduce blood flow to muscles, making them more susceptible to cramps.

7. Acclimatise to the environment in which you perform, especially when moving from cool to warm climates.

Stretch the point

If you do get a cramp, stretching the cramped muscle is the best way to reduce the pain. If it happens in the calf, grab the toes and ball of your foot and pull them towards the kneecap, or get someone to do it for you as shown in the pic. This helps the muscle to relax. Applying ice can also stop the spasm and reduce the pain.

What does it all mean?

If you have access to millions then please start the International Research Unit for Cramp and Stitch. We need it because we know stuff-all about the nuisance pain we all experience. Because humans evolved in a warm environment, it is often said that salt depletion is unlikely to be the cause of cramp in most people, but there have been reported cases of “whole body” cramps in athletes where salt depletion is a more likely cause. Otherwise, it seems that looking after yourself may be your best bet against cramp. If you would like a bit more on the topic, here is a lengthy discussion [http://www.medicinenet.com/muscle_cramps/article.htm].


References: British Journal of Sports Medicine 2009; 43: 401-408

Night cramps

Mollie wrote: “I’m hanging out for cramps info. I am getting terrible ones, especially at night and on waking, especially with sudden movements of legs, and even hands and fingers. Can it be just because I’m getting old? Wearing different, not so comfortable shoes for a day of training seems to exacerbate them.”

Well Mollie, cramps do tend to occur more frequently with age. Lot’s of people do suffer night cramps, so you would think that there would be a whole lot more on the topic.

The Mayo Clinic can describe night cramps [http://www.mayoclinic.com/health/night-leg-cramps/MY00410] but offer no solution, and a British site [http://www.patient.co.uk/health/Cramps-in-the-Leg.htm] gives some tips to reduce night cramps. Oh yes, and stick to comfy shoes.

Sunday, November 21, 2010

Food and Zits

About a year ago I wrote about the link between chocolate and pimples and found the evidence poor. Since then there have been a couple of reviews of the diet data so I thought I would share them with you.

Good parent, bad teenager

Parents have long handed out dietary advice to reduce pimple production, seemingly based more on socially accepted dogma (avoid sugar, soft drinks and confectionery) rather than any good quality research. No doubt, it suited the good parent/bad teenager model of family life. Since the turn of the century there has been some, but not many, well designed studies to try and determine whether our diet does influence acne.

Glycaemic Load

I took a look at a couple of review papers and both agree that the best evidence is that a low Glycaemic Load diet has the greatest ability to control pimples, that is, a diet that has the least effect on blood glucose levels. For example, it means less rice crackers and crispbreads, cornflakes, crumpets, one-minute oats and more fruit, legumes, nuts, vegetables and dairy foods.

Of course, many people are adamant that certain foods trigger their acne, and there is no argument from me. It is plausible that for some folk specific foods or greasy takeaways can be manifest on their face the next morning. Trying to give general anti-acne diet advice to all is the tricky bit.

Other theories

There have been other theories of late, such as a diet rich in omega-3 fats from fish helps protect against acne, but there is no clear link between other aspects of the diet and pimples. There has been conjecture that dairy foods, like skim milk, increases the risk of acne by increasing Insulin-like Growth Factor (IGF-1) production, a hormone that elevates the sex hormones that cause acne. The jury is out on that one. The most convincing evidence remains for the high Glycaemic Load diet.

What does it all mean?

For a start, there doesn’t seem much point in trying to scare those with acne into thinking that avoiding jelly beans and soft drink is a solution. Avoiding the occasional treat is hardly going rid the skin of pimples.

What is clear is that it has been particularly difficult to isolate one aspect of the diet that promotes or defends against acne, meaning that other factors are unavoidable, with adolescent hormones being an obvious one. For example, when you lower the Glycaemic Load of the diet (ie get people to eat better), people of ample size often lose weight and one wonders if the weight loss is equally helpful as low Glycaemic Index (GI) foods in reducing the incidence of zits.

On the other hand, eating well seems to be the most effective way to put diet in your corner for the acne battle. Choosing low GI foods is helpful, except GI is such a difficult physiological concept to get across, so maybe just telling people to eat mainly minimally processed foods will help. Getting them to do so is not so easy.

References:

Journal of the American Academy of Dermatology 2010; 63: 124-141

Clinics in Dermatology 2010; 28: 12-16

Vinegar and your Blood Glucose

When you eat well you limit the excursions in your blood glucose levels, generally making it easier to control your weight, your pimples and your diabetes, should they be problems. It has been known for some time that adding a tablespoon of vinegar to a meal (eg vinegar in your salad dressing) can reduce the blood glucose response to the meal by 30%.

The theory is that adding vinegar to a meal slows down the rate at which food empties from the stomach and enters the small intestine for digestion, therefore slowing the absorption of glucose.

A recent paper (Eur J Clinical Nutrition 2010; 64: 727-732) indicates that the vinegar effect is more pronounced after high GI meals and not the low GI meals we suggest for good health (and less zits). They used a wine vinegar. I assume the effect is still present with a flavoursome 4-clover leaf balsamic.

Tuesday, October 26, 2010

Low joule sweeteners & appetite

Sweetening agents in food or as a powder or tablet have been around for many years. I have already told you that my folks used saccharin during the sugar restrictions of the 2nd World War. Much misinformation on sweeteners circulates the internet because the world loves to hate stuff they don’t understand.

One thought has been that sweeteners like aspartame (Nutrasweet) at best didn’t make you eat less kilojoules and at worst, made you overeat, countering the close-to-zero calories they offer.

Sugar vs sweeteners

Sugar has been thought as a culprit in weight gain since the 1960s, so replacing sugar with a sweet substitute that provided very few calories was always seen as part of the remedy and would help weight loss. To test whether people compensated for the “missing kilojoules” when consuming low joule sweeteners, researchers first gave test subjects a “pre-load” meal that had either sucrose (cane sugar), or the low joule sweeteners aspartame or stevia (a sweet extract from the leaf of Stevia rebaudiana). They were blind as to which pre-load snack they got.

The participants had a controlled breakfast. Later in the day they were given one of the three pre-load snacks, followed 20 minutes later by a regular lunch. In the evening they were given another of the three pre-loads (with either sucrose, aspartame or stevia) followed by a dinner to their liking.

Appetite not affected

The pre-load snack had an extra 200 Cals (835 kJ) when the sugar was added, compared to the sweetener. If the low joule sweeteners aspartame or stevia had no effect on appetite, then the subjects should have made up the difference in kilojoules by the end of the day, such that they ate the same number of kilojoules independent of whether the pre-load meal had sugar or sweetener.

At the end of the day, when the pre-load snack had a low joule sweetener, the people ate around 300 Cals (1255 kJ) less food than those who had sugar included. Conclusion: low joule sweeteners helped lower the amount of Cals/kJs eaten over 24 hours.

Caveats

The pre-load snacks were solid (crackers and cream cheese sweetened with sugar, stevia or aspartame). The results may have been different if the choice was regular or diet soft drink. The people chosen did not have psychological problems with their food. Had they been aware of the kilojoule content of their snacks (or knew they were drinking diet soft drink) they may have made psychological adjustments to what they chose at lunch or dinner. The study was over 24 hours and a compensatory calorie catch-up may have occurred on subsequent days. All the same, this research is consistent with other research suggesting that “diet” food and drinks can help weight control in many people.

What does it all mean?

When I fly I usually have a water, Diet Coke or Pepsi Max (I’m one of those who can’t really tell the difference) to counter the dry atmosphere in an aircraft. The occasional diet soft drink or food with a low kilojoule sweetener can play its part in stopping overeating. As always, controlling your weight is about eating well and being fit. Low joule sweetened foods can help in a small way.

Reference: Appetite 2010; 55: 37-43

Hash brown content of Harley Davidson's

While reading Martin Lindstrom’s book Buyology (http://www.martinlindstrom.com) he mentioned that Harley Davidson had tried to trade mark its engine sound when Japanese bike manufacturers tried to mimic that engine rumble. He described it as the signature fast “potato-potato-potato” sound. I hadn’t heard the sound described that way before. You probably have, and so have many others (put Harley and potato into your search engine).

Ok, nothing to do with food. I just liked the analogy, but not around my house after 10pm please (because the sound wedges into my consciousness and fries my sleep. Hey, I know it’s not funny, but I didn’t think you would read this far). The photo was taken at the Elvis Festival, Parkes, NSW in January 2008. From memory, Kelvin the owner, paid $35,000 for it. And yes, he has the complete Elvis outfit and wig.

Monday, October 11, 2010

Popeye didn't eat spinach for iron


Three generations of children have been told to eat their spinach so they get enough iron and grow up to be a strong as Popeye. Leaving aside the fact that muscle strength has got more to do with training and eating well, more than a focus on a single nutrient, we face those funny things called facts.

Spinach and iron

Spinach does contain iron. Half a cup of cooked spinach provides around 4 mg of iron. That’s pretty impressive considering the average bloke needs 8 mg a day and young ladies need 18 mg a day. Most other vegetables barely give you 1 mg of iron per half cup served. So, spinach has quite a bit of iron. And that’s about as far as some people look.

Although spinach is high in iron it is a lousy source of iron. How’s that? Well, it all revolves around the word “bio-availability”, that is, the ability of the body to absorb a nutrient from the intestines and use it within the body. Most of the iron in spinach is bound to oxalate (in the form of ferrous oxalate) and you do not have a digestive enzyme to split that binding to release the iron. That means that most, estimated at 95%, of the iron goes in one end and out the other about a day later. Spinach is iron’s way of taking a 10 metre (11 yd) voyage through your guts.

The decimal point fallacy

Now, Popeye is unlikely to have known that because he was created around 1929, featuring in his own cartoon in December 1930. A British Medical Journal paper from 1981 claimed that the fallacy of spinach being high in iron came about because the decimal point was placed in the wrong spot in the original analysis back in the 19th century, giving spinach an iron content ten times more than it was in reality.

Earlier this year, Dr Mike Sutton from Nottingham Trent University in the UK, refutes the whole argument stating that there is no evidence that a decimal point was ever placed in the wrong spot. He has even written to author of the BMJ article and says the response from the author provided no proof for the claim.

The really, really interesting bit

Well, to me at least. OK, so spinach is not a great source of iron and it never appeared to be. When Popeye was created in 1930 we knew about the minerals like iron and calcium and only the vitamins A, B1, C, D and E. Vitamins like folate, B12 and niacin were yet to be isolated.

Did Popeye himself say he ate spinach for iron? No. Not once, according to Mike Sutton. He did, on 3rd July 1932, mention that he ate spinach for one particular nutrient. Vitamin A (see cartoon). You and I know that there isn’t pure vitamin A in spinach; it’s in the pre-vitamin A form of beta-carotene. All the same, Popeye ate spinach for a vitamin, not a mineral.

What does it all mean?

It is wonderful when someone goes that extra distance to get information. So, hat’s off to Mike Sutton. I didn’t take Mike’s word for it. I went and bought the first two years of Popeye cartoons (because I yam what I yam), and I agree with Mike: Popeye only mentions vitamin A. Popeye is right, spinach is a great source of beta-carotene (and folate). Eat your spinach for the vitamins, not for the minerals.

If you would like to read the complete report by Mike Sutton then just got to: http://www5.in.tum.de/~huckle/Sutton_Spinach_Iron_and_Popeye_March_2010.pdf. Warning: it is a 35 page in-depth study as you might expect from a criminologist, which is just what Mike is.

Reference: British Medical Journal 1981; 283: 1671-1674

Tuesday, September 21, 2010

Alcohol & Rheumatoid Arthritis

Health advisors often have differing views on alcohol. Is it a healthy drink to help avoid heart disease or is it an insidious and evil beverage that causes social turmoil? I agree with the words of Abraham Lincoln, or maybe his speech writer, who said: “It has long been recognised that the problems with alcohol relate not to the use of a bad thing, but to the abuse of a good thing.” Well, it was more interesting than saying “drink in moderation”.

1-2% population affected by RA

From UK researchers comes further indication that the occasional drink can be helpful and healthful. As alcohol has anti-inflammatory and a mild analgesic effect, they proposed that rheumatoid arthritis (RA) might be less likely or less severe in people who drank alcohol.

According to this [http://www.aihw.gov.au/publications/phe/phe-110-10524/phe-110-10524.pdf booklet] from the Australian Institute of Health and Welfare rheumatoid arthritis is an autoimmune disease in which the body attacks its own organs and joints, especially the joints on the knees, wrists, fingers and elbows. This debilitating condition affects around 400,000 Australians (about 1 in 50 people). It is more common in ladies and older folk.

Don’t smoke; drink frequently

The research compared 873 Caucasians with RA to 1004 without the condition, all from around Sheffield in England. Each one underwent clinical and radiological assessment as well as completing a survey. Those with RA were more likely to be older, smoke and female when compared to the control group. The more frequently someone drank, the less likely they were to have RA, and the less severe were the symptoms if they had RA.

Dr James Maxwell, the lead author of the paper, said: “Patients who had drunk alcohol most frequently had symptoms that were less severe than those who had never drunk alcohol or only drunk it infrequently. X-rays showed there was less damage to joints, blood tests showed lower levels of inflammation and there was less joint pain, swelling and disability”.

What does it all mean?

Note that only frequency of alcohol consumption was measured, not the amount of alcohol, and alcohol consumption was based on a questionnaire, always a problem as humans have lousy memories and like to give socially acceptable answers. Despite this, the protective effect of alcohol against RA was pretty persuasive and cannot be ignored. Like all good researchers, they did say: “Further research is needed to confirm the results.” If they are confirmed, health authorities will hope that only 1, maybe 2, standard drinks does the trick, because then we can keep giving out the same advice as we always do.

Reference: Rheumatology. 2010; doi:10.1093/rheumatology/keq202

Tuesday, September 7, 2010

Is weight loss good for overweight people ?

Sensible answer: of course it is. I mean, haven’t you seen all those public weight loss campaigns? When overweight folk lose weight, their health risks tend towards normal, that is, blood pressure drops, blood glucose lowers and blood cholesterol improves. A good thing, no? Not so fast, say a couple of American scientists who have crunched the numbers.

Intentional vs unintentional

Previous research has revealed that weight loss is linked to an increased chance of dying. Yes, that’s right, weight loss = early death. Clever readers will note that sick people usually unintentionally lose weight before they die, so such people will skew the statistics. There are other confounding factors too. Intentional weight loss is often via an unbalanced and low nutrient starvation diet (do you feel just too vibrant and joyful? Then try the Israeli Army diet) and semi-starvation has never been associated with longevity. These diets often mean a loss of muscle tissue and not just body fat. So, we have to be careful when we say that weight loss increases the chance of early death.

Too much weight loss unhealthy

Anyway, the statisticians looked at over 6000 men and women who were 50 years plus. They were followed for about 20 years and in that time 1600 died. Once they had adjusted for age, health and smoking and all the other things they adjust, guess what? If you lose more than 15% of your weight, whether you are male or female, obese or overweight, you die earlier than if you had lost only 5% of your weight. Women doubled their risk of early death and men increased their risk one and a half times by losing over 15% of their weight.

Let’s say you weigh 120 kg (265 lb) and lost 18 kg (40 lb) then you have probably brought your funeral forward. Are you listening at The Biggest Loser as you cheer Bob or Jane who has gone from 140 kg to 85 kg in a 12 week season?

What does it all mean?

Not every chunky person needs to lose weight. It is well regarded that people over 75 years do better and live longer with a little extra padding. The overweight unwell shouldn’t be placed on weight loss programs either. An otherwise healthy overweight person should lose weight slowly and not use televised “reality” weight loss programs as a guide.

This study is not saying that overweight people won’t benefit from weight loss, but it is making us ask whether encouraging a huge weight loss down to a supposed “ideal weight” is a good idea for everyone. Being very overweight is not healthy; promoting big weight loss doesn’t appear to be wise either. Right now we just don’t know what is a healthy rate or level of weight loss. The current advice for the overweight to lose around 0.5 kg (1.1 lb) a week and accept they probably won’t ever be super-lean is still the best advice.

Reference: International Journal of Obesity. 2010; 34: 1044-1050

Vitamin Supplements

Rod wrote to me and said: "Just returned from a stint in Samoa and have hopefully encouraged a group of people to sign up to your newsletter. I seem to be constantly faced with questions about taking vitamins. My response is usually that if you have a balanced diet, there is no need to take additional vitamins. Many are now responding with the statement that our food is so over fertilised and sprayed with pesticides that the vitamin levels are deficient and therefore we should take extra supplements. Can you clarify?"

Thanks for your note Rod.

If you want people to take more of your supplement, especially vitamin supplements, then you must constantly seed the idea that today's food supply is deficient in whatever nutrient supplement you are trying to convince people to purchase. This style of marketing has been very common over the last three decades. You must tell people that fruits and vegetables now have less vitamins than they did 100 years ago, despite the fact that we didn't even isolate the very first vitamin until 1912, or you tell them that fruits and vegetables are devoid of vitamins without appreciating that the vitamins are there for normal plant function and growth and not specifically for humans.

In this country, as far as we can determine, fruits and vegetables have just as much vitamins and minerals as they did decades ago. The greatest influence on the nutrient content of fruits and vegetables is actually the purchaser. It will depend upon how the produce is stored, how soon after purchasing the produce is consumed, and how the produce is prepared and cooked. But of course, people don't want to hear that. They much prefer to hear the conspiracy theory of food supply.

There are certain subgroups of people who do require additional nutrient supplementation, such as extra folate during pregnancy, additional iron in anaemic patients, vitamin D in those with vitamin D insufficiency. Most healthy people who eat well and are fit are those least likely to benefit from a multivitamin supplement.

In fact, I think, this is a sensible argument, but I do not have the funds to constantly pitch myself against high-profile cricketers flogging supplements to those who can afford them yet will get the least benefit. People find celebrities and athletes more credible than scientists. I live with that every day. Please hand me that box of tissues.

Tuesday, August 17, 2010

Organic food & health

Recently, I popped down to my local organic fresh produce market to see friends Murray and Pam who run the Oranje Tractor organic winery (see pic). Their website [http://members.iinet.net.au/~oranjetractor/] tells you why they spell oranje with a “j”. I grabbed six bottles of their excellent drop and some fruit and bread.

Is the organic food I bought more nutritious? You can bet that most people shopping there believe so, yet we cannot make that assumption. I know I have commented on this before [http://glenn-glenncardwell.blogspot.com/2009_08_01_archive.html], but a new paper suggests there may be no health benefit to buying organic either.

No antioxidant benefit

The review by the London School of Hygiene and Tropical Medicine could find only 12 good quality scientific papers that compared the potential health benefits of organic and conventionally grown produce. Half of the studies looked at the antioxidant activity of produce and the maximum number in any study was only 43 subjects. There was no strong evidence that organic foods boosted antioxidant activity in the blood beyond what would be expected. Even if it did, that doesn’t necessarily translate into less disease or a longer life.

Better studies needed

It is clear that if we are ever to see a health benefit between conventionally grown and organic produce then we need better designed studies in more people for longer periods. Who would provide the funding? The government might argue it is not worth it until we get more than 1 in 10 adults eating enough fruit and veg of any type. Organic produce farmers may not foot the bill because (a) we are talking millions of dollars, and (b) there may be no obvious long-term benefit to health, hence all those funds will be “wasted”.

What does it all mean?

The term “organic” refers to the growing conditions only. Choose local organically grown produce if it suits your budget, just don’t try and read too many personal health benefits into the label, except maybe the pleasure of supporting local farmers like Pam and Murray and being a part of a rapidly growing section of fresh produce sales. Personally, I feel particularly up-healthed after a glass of organically produced shiraz.

Reference: American Journal of Clinical Nutrition. 2010; 92: 203-210

Organic food for weight loss?

A new US study observed people given cookies that were either regular or organic with exactly the same energy content (670 kJ/160 Cals), as listed on the label. Consumers were then asked which they felt was better for their weight. Yep, you guessed it, the organic version was assumed to be lower in kJ/cals and better for their waistline, even when they were prompted to check the label. The more “pro-environment” they were, the more likely they were to judge the organic cookie as lower in energy. A recent UK consumer study found that 15% of people also thought that organic foods were preferable for weight loss.

The “believing more than is declared” phenomena is not new. In the 1980s and 1990s people assumed that “cholesterol-free” meant low in fat and great for blood cholesterol. Even today, very few people understand that the cholesterol level of a food has nothing to do with the fat content or the type of fat. The law has changed (at least in Australia) to stop the indiscriminate used of the term “cholesterol-free”.

The avocado folk stopped putting “cholesterol-free” stickers on their produce because people would prefer “cholesterol-free” avocadoes and avoid those fruit without a sticker. I bet if apples had “No Added Salt” and “Dolphin Safe” stickers they would fly off the shelves.

Reference: Judgment & Decision Making. 2010; 5 (3): 144-150

Tuesday, August 3, 2010

Calorie restriction

You probably have never heard of Clive McCay and this brief article is not about dieting. As we have discussed before, it is easy to over-eat due, in part, to an abundance of food and encouraging genetics. Calorie restriction is what every (yes, every) weight loss diet promotes, but what of calorie restriction in the lean?

Fewer calories, longer lifespan

It was 1935 when Clive McCay wrote the first paper detailing an increased life span when food was restricted, as opposed to animals that had ad libitum feeding. Subsequent research suggested that restricting energy (calories/kilojoules) alone was the cause of an extended life, providing that all the essential nutrients were provided. Energy restricted laboratory animals were living about 20% longer than animals eating whenever they liked.

Fewer calories, less cancer

Even as early as 1942 it was noticed that energy restricted animals also had less spontaneous tumours leading one researcher to say: “__It follows that the avoidance of overweight through restriction of food intake may aid in the prevention of human cancer or at least delay its onset.__” That idea was a whole lot more likely in 1942 compared to around-the-clock eating in 2010. The idea still has merit as overweight people are more prone to cancer than lean folk.

More fasting, fewer calories

A 1946 paper acknowledged that natural energy restriction would be difficult in humans as they have a strong in-built desire to eat. They found that rats that were occasionally energy restricted by being fasted 2-3 days a week also had an extended lifespan and less tumours.

With humans long fascination with looking and feeling young, there have more recently been human studies on energy restriction. Like other animals, it seems that less food means better health and a longer life, although the effectiveness in humans is not yet definite due to our relatively long lifespan (lab rats live for 3 years; many humans clock up 85 years so you would have to track humans for 100 years before you might have the definitive answer).

What does it all mean?

If you are happy to under-eat once you reach adulthood, then there is a reasonable chance that you will live longer than normal. It will mean no chocolate, cabernet sauvignon, brie, premium ice cream and many other flavoursome foods. I would struggle there. It will also mean being active all your life. Happy with that angle.

The reality is that two-thirds of the population in a western country over-eat and hope that pills, crack-pot diets and surgery will conquer the excess. Energy restriction in western countries doesn’t appear to be achievable. Energy restriction, like human rights, world peace and the French football team, looks good on paper.

Reference: Journal of Nutrition. 2010 (July); 140: 1205-1210

What was the first artificial sweetener

I once answered this question in a newspaper article last century. The sub-editor thought I had made a mistake so added 100 years to the answer. We have been using sugars and honey as a sweetener for millennia. The next sweet agent to get attention was saccharin in 1880 (not 1980, sub-editor).

Saccharin is from the Latin word for sweet. It was first isolated by Ira Remsen and Constantine Fahlberg at Johns Hopkins University in the US. Fahlberg was smart enough to patent the production method and became wealthy through its commercial manufacture in Germany. Remsen and Johns Hopkins never made a cent from saccharin.

Saccharin is cheap to make so it became a sugar substitute during both world wars. My parents remember its taste through the 1940s before sugar became more available.

Saccharin has attracted plenty of attention over the years through mainly negative commentary, in the 1980s especially. It is now widely considered as safe for human consumption after scientific scrutiny, being approved for use in over 100 countries.

Source: That’s the Way the Cookie Crumbles by J Schwarcz (ECW Press, Toronto 2002)

Tuesday, July 20, 2010

What is in control of your appetite 2

In an earlier blog I mentioned that there is an internal drive to eat, grow and reproduce and this seems to over-ride the decision to eat well for a long life. We tend to over-eat to contend with famines although most of us haven’t experienced a food shortage since television.

Protein is life

We know how much protein is needed for growth and maintenance yet nearly all of us eat more than we need and actively seek high protein foods. In the US 97%, and in Australia over 90%, of the population eat more protein than needed (around 0.8g/kg day). As countries “develop” they tend towards an increase in protein intake. We love big steaks, seafood platters and, of course, triple bacon, double cheese, egg, thin slice of tomato for colour, megaproteinburgers.

A theory is that a high protein diet brings forward the onset of puberty and so extending the period of fertility. In affluent western societies the onset of women’s menarche is 11 years, while in rural China it is 17 years.

Protein is death

The bad news is that the desire to track down protein is linked to a shorter life. A moderate protein, calorie-restricted diet increases the lifespan of laboratory animals by around 20% compared to high protein diets. On the other hand (and I’m so glad we have two hands because there are so many on-the-other-hand situations in life) high protein foods are more satisfying than high carbohydrate foods so people are more likely to stop eating before they get too podgy. In theory.

Health campaigns ignore genes

We love food. Nature designed us that way. We love calorie-dense foods with plenty of protein and fat (hamburgers), and protein, fat and sugar (chocolate). The authors of this paper argue that our in-built tendencies are usually ignored in health campaigns and scientific study. For example, a campaign urging us to eat low calorie fruit and vegetables doesn’t make sense to our genetic desire for calorie-dense foods.

What does it all mean?

We were never designed for a long life, just a life long enough to get our children to reproductive age, so four decades is about all that is expected. And millions eat like they are happy with four decades before they clutch their chest and hit the floor. Dietary advice today runs counter to our natural instincts to eat foods that give us both pleasure and calories/kilojoules to reach a reproductive age.

Living to the age of 80 years is a relatively new experience for humans. Before the industrial revolution, 40-50 years was about all you could expect unless you were gentry. Go back 1000 years and you were looking at 30-35 years to be labeled “old”. For those us who are aiming to clock up eight or ten decades then eat like you want to live to 100, and live like you might die tomorrow. Just know, it won’t be easy.

Reference: Appetite. 2010; 54: 442-449

Banana vending machine

I read with interest that Japan launched its very first banana vending machine on June 23rd in Tokyo’s Shibuya station. Fruit in a vending machine is a novel idea and should be applauded. I just hope that after you pay your $US1.50 for a single banana ($US4.50 for a bunch) that it gets treated gently by the machine and doesn’t drop the equivalent of six banana stories from the top of the machine.

Dole, the biggest fresh produce company in the world, has provided the machine. When I squint hard enough, I’m pretty certain that Captain Banana, if that’s his name, has a banana mo.

Monday, July 5, 2010

What is in control of your appetite?

With democracy and affluence comes overweight, poor food choices and laziness. OK, not laziness, just the decision to remain on one’s bottom for hours and hours. Why don’t people in well-off countries eat more healthy and get out and boogie? Find a solution to that and you can write your own ticket.

Genes meet environment

A bunch of European scientists believe that part of the problem is that some nutrition decisions are genetically determined and very difficult to change. It seems that the environment doesn’t change your genes, but it does determine which genes are turned on and off.

Having abundant food around increases the individual limit for food to be satisfying. One paper showed that changing to a healthier diet for a few weeks modulated the response to over 500 genes. In other words, gene expression returned to normal. Sadly, the environment tends to over-ride this for many as we are surrounded with eat-me, buy-me cues, returning gene expression to over-eating.

Time of the season

Animals that experience seasonal or daily variation in food availability (think of hibernating or hunting animals) tend to eat more than is necessary when they find food. They store the excess food as body fat, which is then used during times of food shortage. When these animals experience long-term abundance they over-eat. Humans are one of these animals. In affluent democracies not only are half of the humans overweight, half of the cats and dogs are too.

It’s not just humans that prefer processed and cooked food, the great apes are a big fan as well. Many other wild animals prefer cooked food to raw. Choosing foods that are rich in kilojoules means that an animal will grow faster, reach reproductive age quicker, protecting the survival of the species. The authors argue that this hard-wiring to eat, grow and reproduce is one reason we choose cooked and processed high kilojoule/calorie foods over minimally processed foods.

Gene defect

There are the unfortunate who have a specific genetic defect that drives them to eat too much, such as Prader-Willi syndrome. I used to look after kids with this syndrome when I worked at the Children’s Hospital in Sydney deep in the last century. By default, I became the Australian expert on PWS and spoke at conferences. It’s tough for parents when you have to lock all food cupboards and the fridge because your child’s appetite has no off switch. Ever.

What does it all mean?

Now, I can’t say I fully understood this paper, but the jist seems to be that we are similar to other animals in that we are genetically geared towards over-eating as that makes us more likely to survive famines, live to maturity and reproduce. Go to the paper if “epigenetic mechanism of methyl–cystine bonding” in gene expression sparkles your mind.

It also means, and this bit is worrying me, that if you have children and have now brought them up to a reproductive age, then you are no longer required by nature. Watch your back.

Reference: Appetite. 2010; 54: 442-449

What does the M in M&Ms stand for?


I answered this question for the local paper recently. Even most people at Mars don't know the answer to this. They, and others, mistakenly presume that both Ms stands for Mars, yet they are called M and Ms for a reason.

M&Ms were first produced in 1941 from an idea by Forrest Mars when he saw soldiers in the Spanish Civil War eating sugar-coated chocolate. The sugar coating protected the chocolate from melting and this inspired M&Ms, a chocolate that "melts in your mouth, not in your hand". The first M in M&Ms is for Forrest Mars, the inventor of M&Ms.

William Murrie was president of the Hershey Chocolate Company. His son, R. Bruce Murrie, became a partner with Forrest Mars in his project and he helped Forrest acquire and modify Hershey plant machinery to be able to produce M&Ms. The two of them initially set up the company M&M Ltd.

The second M in M&Ms stands for R. Bruce Murrie. Some sources say the second M stands for his father, William Murrie, as he had given his blessing to the partnership.

Forrest Mars eventually bumped R. Bruce Murrie out of the partnership, hence people at Mars say the Ms stand for Mars and Mars, while historians at Hershey say the Ms stand for Murrie, a well-known Hershey family ... and Mars.

Source: The Emperors of Chocolate by JG Brenner (Broadway Books, New York 1999)

Wednesday, June 23, 2010

The dehydration myth

Last month a fruit juice company put out a press release stating that there was new research that 52% of Australians were dehydrated. Evidence provided – zero. We just had to take their word for it.

The 8 glasses myth

Later in the press release came the statement that 64% of us aren’t getting the “recommended eight glasses of water a day”. Who made that recommendation? We are not told. Don’t bother looking either because I have never seen a health authority in the world make that statement. Do you drink 8 glasses of water a day? I don’t. It’s winter here. During summer I might, especially if I’m out on my bike. In winter, sitting at my puter I’d much prefer a hot cuppa thanks.

No single level of water intake

Do you really need to drink 8 glasses of water a day? No. There is no harm in doing so and if water is the only drink you have then it is probably a smart decision. The official Nutrient Reference Values (NRV) we have in Australia state “there is no single level of water intake that would ensure adequate hydration and optimal health for the apparently healthy people in the population”.

The NRVs suggest an average intake of 3.4 litres a day, based on the assumption that 800 mL will come from foods like pasta, apples and potatoes and the remaining 2.6 litres will come from non-alcoholic fluids like milk, tea and coffee. (Note that 2.6 litres is about 8 glasses; it doesn't have to all be drunk as water).

What about caffeine?

The first question that comes to mind is “Don’t caffeinated drinks dehydrate you?” The simple answer is no, they don’t. If you do drink tea, coffee, or cola you will need to pee out some of the metabolites of caffeine but this obligatory urine is a lot less than the fluid in the drink. For example, for a 250 mL cup of tea, your obligatory urine needs are around 50 mL, leaving the other 200 mL as part of your fluid intake. Only alcoholic drinks have a dehydrating effect. For more detailed science on hydration and caffeine download my free ebook called Nutrition Fibs [http://fsplugins.com/shopwindow/glenn/E-Books].

What does it all mean?

Drinks like soft drink, fruit juice, tea, coffee and milk, and foods like fruit, vegetables, meat, yogurt, soups, stews and steamed rice all have appreciable amounts of water that contribute to your fluid intake. Water is an excellent fluid too; it’s just not the only fluid as some imply. Under normal day-to-day circumstances if you pee every 2-4 hours and your pee is lightly coloured then you are likely getting enough water each day. And that marvel called nature also offers a helping hand when your body gets low on water – it makes you thirsty. How neat is that?


World champion soft drink guzzlers

A food magazine recently listed the soft drink consumption by continent or region. Australasia consumed 19 litres per capita while America consumed 161 litres per capita. (Yep, eight time as much). Now, those figures are misleading because Australasia probably includes small Pacific islands and America would include Chile and Bolivia, countries likely to have a lower consumption of soft drink than Australians or US citizens.

I did find a website that listed 18 countries by soft drink consumption [http://www.nationmaster.com/graph/foo_sof_dri_con-food-soft-drink-consumption]. As expected the winner was the US with 216 litres per capita. Wow, that’s every kid and adult drinking over 1.5 cans (or 600 mLs – 1 pint) every day of the year.

Australia was #6 with 100 litres, UK #7 with 97 litres, the Kiwis are #9 with 84 litres and Japan is #18 with 22 litres. I suspect this only includes countries that keep statistics and is not the “top 18” soft drink guzzlers on the planet.

Monday, June 7, 2010

Multivitamins & breast cancer

The multivitamin pill is a favourite supplement of people who are “well and would like to stay that way”. They are usually taken as insurance so they know they are getting all the main nutrients each day.

Big study hints at problem

Vitamins and minerals are found in a range of foods so they are considered “natural”, but taking large doses in a tablet form is quite unnatural and this is rarely mentioned. Before vitamin supplements became popular in the 1970s there were no studies indicating they were safe because it was assumed that natural = safe. Most scientific reviews have shown little advantage for general health when taking specific vitamins or multivitamins, partly because those that take them are both moderately well-off and moderately well.

A Swedish study of over 35,000 women who were tracked for 10 years has indicated that taking a multivitamin could increase the risk of breast cancer. Multivitamin use was associated with a 19% increase in the risk of breast cancer. Women who had taken multivitamins for more than three years had a 22% increased risk. Those who took calcium tablets had a decreased risk of breast cancer. Other studies have shown a link between multivitamin supplements and breast cancer, while others haven’t, so there is no clear direction yet.

Some supplements useful

We do know that supplements may be helpful in specific circumstances. Pregnant women are told to take folate and iron because their increased needs can be tough to get by food alone. Calcium supplements can be helpful to those who aren’t big fans of dairy food. With possibly one third to one half of Australians being vitamin D deficient during winter means a vitamin D supplement. or more midday sun, is required. Vitamin supplements may also be useful for backpackers relying on a limited range of food or during long periods of illness.

What does it all mean?

If you look after yourself, there is probably no advantage to taking a multivitamin for a shot-gun spray of nutrients. If you prefer to take one, then chose one that provides the vitamins and minerals in amounts equal to the daily needs (Recommended Dietary Intake – RDI) or less. The perfect multivitamin would provide about 30-50% of the RDI, but this is not great for marketing – people like to see bigger numbers, so many supplements provide much more than is required leading to the “expensive urine” comments.

Please remember one really important thing: by taking vitamin supplements you are part of a giant experiment. There is a lot we don’t know about the long term effects of supplements. Don’t be surprised if more research shows that taking vitamins as a supplement in doses more than is required could be harmful down the track. The best evidence for a long life is to eat well.

Reference: American Journal of Clinical Nutrition. 2010; 91: 1268- 1272