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Food Facts & Furphies

Food

More than 50% of Australians are taking some form of vitamins, minerals, complementary or herbal supplements yet the average Australian household spends just $13.70 per week on vegetables and $9.60 on fresh fruit.

By Clare Collins

New diet fads and furphies seem to appear every day. While some of these have a scientific basis, for others the science has changed in response to new discoveries or the science is just not there yet. This special issue of Australasian Science explores the latest evidence for food and nutrition.

“I took this rare superfood that only grows on the southern slope of an exotic mountain for 2 weeks per year and must be hand-picked at dawn. It costs $40 per kilo.” When I hear stories like this I cringe and wish I could convince people to save their $40 and spend the money on more vegetables and fruits. The evidence is clear that eating more fruit and veg will lower your risk of weight gain and of developing common conditions such as Type 2 diabetes, heart disease, stroke and some cancers.

Low fruit and vegetable intake is one of the top ten risk factors contributing to global mortality. About 1.7 million deaths worldwide are attributable to low fruit and vegetable consumption, as well as 14% of the deaths from gastrointestinal cancers, 11% of deaths from heart disease and about 9% of deaths from stroke. Yet we seem to love spending money on pills and potions that promise a quick fix, but for which there is almost no scientific proof they work. What can we do to change this?

The supplements and complementary medicines industry is estimated to be worth about $1.5 billion per year in Australia, with a growth of about 12% per year. More than 50% of Australians are taking some form of vitamins, minerals, complementary or herbal supplements. This is in stark contrast to 2009–10 data from the Australian Bureau of Statistics Household Expenditure Survey, which reported that the average Australian household spends just $13.70 per week on vegetables and $9.60 on fresh fruit yet $32.35 on alcohol.

There is obviously a long way to go in terms of helping Australians interpret the knowledge we already have about the phytonutrients in vegetables, fruits, herbs and spices, and an even bigger job ahead in terms of helping them learn how to shop, cook and plan to eat healthy food on a regular basis.

My research is tackling the issue of poor eating habits on a number of fronts. We have been working with schools in communities experiencing socio-economic disadvantage, and are helping them run an after-school cooking program called Back-to-Basics ( http://cookingmattersaustralia.com.au/) that teaches children how to cook and enjoy new vegetables and fruits. Parents drop in at the end when they collect their children, view a nutrition display related to healthy eating and then share the meal and take samples of the new vegetables so they can make it again at home.

When it comes to young adults we are doing research looking at what might motivate them to eat better. Not surprisingly they have told us in a number of surveys that feeling better about themselves and feeling that they look better is important. So we are working on this in collaboration with researchers from St Andrews University in Scotland.

It turns out that when you eat more brightly coloured vegetables and fruit that some of the colours, called carotenoids, end up in your skin. These are the food factors responsible for that “healthy glow”. What is fascinating, however, is that other young people can detect these carotenoids and perceive others with higher skin carotenoids levels to be more healthy and attractive. So now we are on a mission to identify which vegetables and fruits you need to get this effect, which are most potent and how long it takes until others notice the result.

Meanwhile the best advice is to simply eat more fruit and vegetables and to have a bigger variety. This means having more at every meal and snack, which means buying a bigger variety. When you have to contribute a plate of food for a get-together, take a fruit platter or some carrots and celery sticks, baby tomatoes and a beetroot dip.

So what do you do if you, or someone you love, really hates vegetables. Don’t despair: they may just be a “super-taster” who has the ability to detect a bitter-tasting chemical called phenyl­thiocarbamide (PTC). If you inherit two copies of the PTC gene, one from each of your parents, then you are super­sensitive to even low concentrations of PTC. This means you may find that some vegetables taste up to 60% more bitter compared with people who do not have the super-taster gene. Vegetables that super-tasters will find more bitter include watercress, bok choy, cauliflower, radish, swede, turnip, Brussels sprouts, broccoli and cabbage. Being a super-taster may have offered a survival advantage in ancient times because it also conferred the ability to taste other bitter substances that were usually toxic, and this would have prevented poisoning.

The good news is that even super-tasters can learn to love vegetables with repeated exposure to them. The first step is to stop refusing to trying them, then tolerating them until repeated exposure to them eventually wins and you don’t mind them so much. It does take some effort, but others will eventually notice that you now have“the glow”.

If you live with a determined vegetable-hater then hiding them in food is much better than not having them at all. You can also have more fruit and less vegetables if you prefer that as a way to boost your carotenoid intake.

The main thing is to get your carotenoids from foods and not supplements. This is really important. The most well-known evidence comes from epidemiological research that associated eating more fruit and vegetables with a reduced risk of lung cancer. A number of clinical trials then got underway to give people supplements of ß-carotene, which is a major carotenoid in orange and yellow vegetables and fruit such as pumpkin, carrots, rockmelons and mangoes. However, this had the opposite effect – it actually increased the risk of lung cancer in smokers and those with previous exposure to asbestos. Although many Australians sometimes take vitamin or mineral supplements for preventive health reasons, the Australian Dietary Guidelines advise us to get our nutrients from foods wherever possible as the safest way to optimise our health.

I have created the Healthy Eating Quiz as a way of checking how closely your current eating patterns align with the Australian Dietary Guidelines. You can rate your usual eating patterns in 5 minutes at www.healthyeatingquiz.com.au, and then print or email yourself the suggestions about how to eat better.

The Healthy Eating Quiz is a diet quality index, and the higher your score, the better your nutrient intake pattern. This means that those who score in the 40s have lower saturated fat and higher intakes of fibre and many vitamin and minerals compared with those who score less than 25. In my review of the relationship between higher diet quality scores and health and well-being, those with the highest scores live longer and have lower risk for heart disease, Type 2 diabetes and some cancer. Interestingly, this relationship is even stronger in men than women. So there is no time to waste when it comes to increasing your intake of vegetables and fruits.

In this issue you will find some interesting facts and a few furphies about the relationship between the food you eat and their supposed health effects. For some foods, such as tea, coffee, carbohydrates and beer, the evidence changes as sciences uncovers new facts and associations with health and well-being. For others, the known health effects are explained as the role of specific phytonutrients are identified or functional food components are isolated and subsequently added into fortified food products.

Some of the articles in this issue clear up the confusion surrounding topical issues such as whether to eat carbs or not and what is the best way to lose weight. Others explain the state of issues such as food addiction, diet and mental health, and whether delving into your genetic profile is going to change the foods you should eat.

This issue will whet your appetite for food and nutrition research, bring you up to date on some key issues, and hopefully leave you with a hunger to follow the science as research brings us new facts related to food, nutrition and dietetics. Happy reading!

Professor Clare Collins is Co-Director of the Priority Research Centre for Physical Activity and Nutrition and a nutrition and dietetic researcher in the School of Health Sciences, Faculty of Health and Medicine, The University of Newcastle. She is a Fellow of the Dietitians Association of Australia.