Thursday, July 25, 2013

Sweetening agents

Sugar and honey

Sugar and honey have been a favourite way for humans to sweeten foods for years. Stinging bees were worth the threat to get to the honey reward. Cave paintings found in Spain depict honey collecting 8000 years ago. Certain ants in the Northern Territory of Australia store honey in their abdomen, to be used later as a food source for worker ants. Local indigenous people regarded these honey ants as a delicacy.

During World War II sugar became scarce. My father remembers using saccharin as a sweetener during the 1940s in England until sugar became more available. As sugar provides Calories/kilojoules, by the 1970s the world was looking for a low-joule version of sugar to help them keep control of their weight. Those with diabetes were also keen to avoid sugar-sweetened foods and drinks to help them control the sugar (glucose) levels in their blood.

During the 1970s the main low-joule sweeteners were saccharin and cyclamate. They weren’t the greatest tasting sweeteners, certainly not a patch on sugar, but it did mean people could drink calorie-free sweet drinks without affecting their blood sugar levels or weight. Those of a certain vintage will remember the drinks Tab and Tresca.

By the1990s new low-joule sweeteners were available and had a more pleasant taste than saccharin and cyclamate, both subsequently going out of fashion. Let’s take a quick look at some of the more recent sweeteners that have arrived in the food supply.

Probably the best-known intense sweetener is aspartame. It was discovered by accident in 1965 and approved for use in Australia in 1986. I remember the time well because I was working with teenagers who had diabetes and they hated the bitter aftertaste of diet drinks and were looking forward to drinks with aspartame that tasted more like they had sugar. Now aspartame is used in food and drinks in over 100 countries around the world.

Aspartame is merely a very small protein, comprising phenylalanine and aspartic acid, two amino acids found in much larger amounts in every protein-containing food that you eat, from bread to meat. This small protein just happens to be 200 times sweeter than table sugar. Strange, but true.

Yes, you will still hear negative stories about aspartame, especially via the internet and through your email inbox, but we have had nearly 50 years of studies showing that this low-joule sweetener is perfectly safe to consume in the amounts found in the diet. There is certainly no evidence that it causes brain tumours, the enduring concern that is often aired.

As it has phenylalanine, food and drink with aspartame will carry a message to parents with children who have the rare condition Phenylketonuria (PKU). About one baby in 10000 births in Australia will have PKU. With 300,000 babies born each year in Australia, that makes about 30 new cases of PKU. These children have controlled amounts of phenylalanine in their diet so they can lead a very normal life. Too much phenylalanine will cause brain damage in these children.

Acesulphame Potassium (K)
This sweetener was discovered soon after aspartame. It is also a low-joule sweetener about 200 times sweeter than sugar, which means that very little needs to be used to give the same sweet taste as sugar. Often it is used with aspartame to get precisely the right type of sweetness required for the food or drink, such as desserts, puddings, canned food, confectionery and soft drinks.

Like all low-joule sweeteners introduced to the Australian food supply it has been passed by our scientific and regulatory bodies, the National Health and Medical Research Council and Food Standards Australia New Zealand.

Around the world, before any sweetener can be used, it is assessed by the Joint FAO/WHO Expert Committee on Food Additives (JECFA), the Scientific Committee for Food of the European Union, and the Food and Drug Administration in the US.

Despite what you often hear, food companies cannot add any food additive they fancy, nor add them in amounts that suit them. They are all very tightly regulated and used in food and drink with at least a 100-fold safety margin, and that includes all the non-sugar sweeteners.

Sucrose has a similar structure to table sugar, although it is about 600 times sweeter than sugar. Like all sweeteners, it has undergone extensive testing since it was discovered in 1976 by researchers at Queen Elizabeth College in London. More than 100 studies have been conducted on sucralose since its discovery, with no safety concerns found. It is permitted for use in food and drinks in nearly 40 countries, including here in Australia, as well as New Zealand, Canada and the United States.

This is the new kid on the block. We can’t really say it has been recently discovered because the natives of the area we now call Paraguay have been chewing on the Stevia plant for millennia. I have tasted the leaf from a home grown stevia plant and it definitely has a sweet taste, although not the same as sugar (so two leaves is my limit). The dried stevia leaves are soaked in water to unlock the sweet compounds in the leaf (known as steviol glycosides), which are then purified. This extract tastes more like sugar, yet has no kilojoules.

The safety of stevia sweeteners has been established based on their long history of use and more than 25 years of scientific research on the sweet-tasting components in the stevia leaf. All the major regulatory bodies around the world have approved it. Stevia is usually not used alone as its sweetness is most effective when in combination with some sugar, hence you will find drinks with only one third of its sweetness provided by stevia and the rest by sugar.

What does it all mean?
Non-sugar sweeteners have been used for a long time since saccharin was first isolated in 1878, over 130 years ago. We have been able to find a range of low joule sweeteners, whether by pure luck, or by searching the plants of the world for their natural sweetness. All the sweeteners have had their safety established before food companies can use them in a very tightly regulated fashion.

The benefits to using non-sugar sweeteners, especially in drinks, is that consumers can enjoy a refreshing drink with next-to-no kilojoules and no effect on blood sugar levels. That makes them ideal for people trying to control their weight or their blood sugar levels.

Sweeteners have no magic properties. Downing a diet drink won’t make you lose weight or make diabetes disappear. Having a ‘diet’ food in one hand and a donut in the other won’t have a cancelling effect. Low-joule drinks and diet foods always need to be part of sensible eating, not a substitute for it. Make wise use of them.

Position of the Academy of Nutrition & Dietetics: Use of nutritive and non-nutritive sweeteners. J of the Academy of Nutrition & Dietetics 2012; 112: 739-758

Raben A, Richelsen B. Artificial sweeteners: a place in the field of functional foods? Focus on obesity and related metabolic disorders. Current Opinions Clinical Nutrition Metabolic Care 2012; 15: 597-604

Sunday, July 14, 2013

Calorie labelling on fast foods

In some parts of the world your favourite fast food will list the Calories or kilojoules next to each menu item. You assess your hunger, check your three yummiest choices, then wisely ask for the one with the lowest number next to it. I mean, you don’t want to be buying bigger clothes any time soon.

You can now classify yourself as weird. Ok, extremely unusual. Not many people do that.

A New York study of lunch time selections determined whether menu choice was influenced by having the energy level next to it. They checked 168 venues of the top 11 best-selling fast-food chains about a year before and a year after the introduction of Calorie labeling began in mid-2008.

On the face of it, no big difference
Overall, there was no change in the number of Cals/kJs chosen from the menu. Before Calorie labeling, people chose 828 Cals (3465 kJs) for lunch, after 846 Cals (3540 kJs). Statistically, that is no difference. Not good news.
Looking at the results further, there were some differences worth noting.

First, we need to know that this study was done in adults who could speak English. No kids or under 18s. Although customers were chosen at random, they knew they would have to hand their receipt to a data collector (in exchange for a free public transport pass as reward). True, that shouldn’t influence their choice, but it may have.

Over half of the venues were McDonalds and Subway, with pizza chains the next biggest proportion of the venues surveyed. And this was New York. Might be different in Wellington, NZ, southern Wales, Port Moresby, or that little place outside of Victor Harbour, South Australia.

About 1 in 7 made lower energy choices
When deciding on lunch, 15% said that they used the Calorie information. As you can guess, women were more likely than men to choose lower Calorie options, and this decision was also more common in wealthier neighbourhoods than in the poorer areas.

Those that used the Calorie information had a lunch with 100 Cals (420 kJs) fewer, on average, compared to those that ignored the information.  Not a lot, but it could be very significant over a year if they regularly bought their lunch at that venue.

McD down, Subway up
Reductions in energy consumption were more common in venues with a wider a range of choice. So, McDonalds customers ate 45 fewer Cals, KFC 60 Cals, and Dominos Pizza fans ate 280 fewer Cals. Note that the pizza eaters were still munching on 1000 Cal (4200 kJs) lunches after the reduction, still probably more than their body really needed.

At Subway, the energy content of each purchase actually jumped 17% from 750 Cals (3140 kJs) to 880 Cals (3685 kJs). What happened there? Well, the second survey was done during a cut-price promotion, a reminder that price has a lot more power than health when it comes to eating decisions.

What does it all mean?
You will recall the expression: “You can lead a horse to water, but you can’t make him wear a bikini.” Health authorities can deliver wise messages, make it easier for the customer, yet in a democracy the consumer wields the power and will make their own decisions, healthy or not. In this case, about 1 in 7 did make a smarter decision, but this can be over-ridden by meals being “on special”.

Chocolate & Nobel Laureates

You all know that there is a big difference between an association, or correlation, and a case of cause and effect. The more televisions you own, the more likely you are to die early of heart disease. Could it be the light emission from the TV, or even something deadly from the weather report? Of course not. The more TVs you have, the more time you are likely to watch telly, the less likely you are to be out walking the dog, and you can complete the explanation yourself quite easily.

Last year there was a report in the New England Journalof Medicine demonstrating that there was a direct link between the national chocolate consumption and the number of Nobel laureates from that country. It was speculated that all those flavanols in the cocoa were a boost to thinking and chocolate consumption should be widely promoted for a higher national IQ.

The media, not being a discerning beast, didn’t read the article properly. If they had they would have twigged that it was written tongue in cheek. Instead, it was reported as a cause and effect and not just an association.

An article published last month in the Journal of Nutrition pointed out the folly of choosing a single correlation to make an assumption. Tea and wine also contain the antioxidant flavanols, yet there is no such association between consumption and brain power for these two popular beverages.

On the other hand, there is a very strong link between the number of Noble laureates and the number of IKEA stores in that country.

And that, surely, is proof why you need to throw out that old sofa and head down to IKEA. Today. You will think so much clearly.