Biotechnology can improve health
In its broadest sense, the history of food and nutrition is that of biotechnology. The current fascination with advanced genetic and production technologies has tended to obscure the fact that biotechnology has been critical to the food industry and to human health for millennia.
Preservation techniques using live organisms (such as yeast for brewing or bacteria for yoghurt manufacture) have been around for a very long time and they show no sign of being superseded. Similarly, selective breeding of domesticated animals and plants has made them almost unrecognisable compared to the original wild types. Modern oranges have been tailored to human tastes and are quite unlike the small, very bitter native fruit.
In Australia, selective breeding of plants, cereals in particular, has been central to the food industry. One spectacular (but largely unrecognised) example is the selective breeding of cereals (especially wheat) to cope with the excessive levels of boron in large tracts of the country. Some 30 per cent of agricultural land is affected by this toxicity and the selection of resistant cultivars has given us high yields from otherwise unusable soil.
Biotechnology has helped to meet the most important driver for nutritionists: a stable and adequate food supply. Many of the new challenges in nutrition are now a result of that success – the so-called ‘diseases of affluence’.
Historically, most causes of illness and death in human society were infectious diseases, secondary to poor community and personal hygiene. These have largely disappeared through improved public health measures – water purification, sewage and waste disposal and immunisation, for example.
Inadequate intake of major nutrients (fats, protein and carbohydrates) and vitamins and minerals have also been neutralised. The problems that are prevalent in Australia and similar advanced countries are those of over-nutrition.
The data on adult and childhood obesity in Australia are well known, as are some of the consequences – diabetes and early-onset coronary heart disease. Less obvious are the high rates of colorectal cancer, which is responsible for more than 4400 deaths a year in Australia alone.
All of these conditions are expensive in terms of individual and community economic costs, as well as the personal distress they cause. Chronic conditions such as inflammatory bowel diseases are also costly. These can be managed with drugs and so become problems of long-term maintenance, rather than premature death.
In addition to direct medical costs, there are hidden imposts such as loss of productivity. These are not just problems of visibly affluent countries, they are beginning to appear in countries, historically, at low risk. Countries such as India, Malaysia and China are beginning to experience a very substantial rise in diabetes, coronary heart disease, inflammatory bowel disease and colorectal cancer. Perhaps the most spectacular of these is Japan, which has gone from very low in the international league table for colorectal cancer, to number one in little more than 20 years.
These secular trends are clear evidence that environmental factors (rather than genetics) are intimately involved in disease aetiology and thus offer an opportunity for prevention.
Prospective population surveys inform as to possible preventive strategies and prevention is cheaper and more effective than cure. In these studies, large groups of people, usually at several centres, are surveyed as to their dietary and personal habits and then followed for an extended period of time. Clinical outcomes are linked to factors that raise or lower risk.
One example is the European Prospective Investigation into Cancer and Nutrition (EPIC) in which 500,000 individuals from 10 countries have been followed for an initial period of five years. It is in the implementation of preventive measures from studies such as EPIC that advanced biotechnological techniques meet some of the important needs of nutrition research.
One of the key findings of EPIC is a dose-dependent reduction in colorectal cancer risk by dietary fibre. In general, supplements are an ineffective means of increasing population fibre intakes and raising the level of fibre in convenience foods is much more likely to succeed.
The fibre content of foods can be increased by processing, but selecting new cereal grains with higher dietary fibre is a better option. This is where there is a collision between consumer attitudes and technology. Conventional breeding achieves this goal, but it is a relatively slow process relative to gene manipulation techniques.
The modern food supply is made up largely of processed foods characterised by their rapid and complete digestibility in the human small intestine. For starch, a major nutrient in most diets, this translates to a rapid (and complete) digestion that floods the circulation with glucose, leading to a high glycaemic index (GI) and greater demand for insulin.
For both the prevention and management of diabetes, low GI has clear advantages and, through the Flagships Program, CSIRO is working to develop new cereal varieties with low GI through gene modification and conventional breeding techniques.
GI is a measure of the rate of starch digestion and controlling its extent is also important. Some starch escapes into the large bowel where the products of its fermentation by the bacteria appear to play a key role in lowering the risk of colorectal cancer and inflammatory bowel disease. This starch – resistant starch (RS) – is low in processed foods and, using gene silencing, CSIRO has generated a wheat variety high in RS. This is a clear example of the application of advanced gene technologies being used to meet a nutritional need for substantial community benefit.
This benefit is not limited to Australia and other developed countries, but also to emerging ones, where the problems are just as acute. However, it does raise one of the key issues in the adoption of new technologies: consumer acceptance.
The unmet needs are global and immediate, so speed of delivery and broad application are essential, but the well-known resistance to the technology remains.
This may be resolved through acceptance of the benefits by at-risk consumers (for example, those with diabetes) who then become users and advocates. It is also worth remembering that application of new technologies leads to new products and this innovation leads to new knowledge.
In my view, nutrition research has been, and always will be, a dynamic activity.
Dr David Topping FTSE, is a Chief Research Scientist at CSIRO Human Nutrition. His current research interest is the health potential for gut health of processed foods, particularly dietary carbohydrates (fibre, resistant starch and oligosaccharides), probiotics and dietary fats. After completing his Doctorate in Biochemistry at the University of London in 1973, Dr Topping embarked on a research career in institutions in the UK, Canada and Australia. One of his key research objects is to improve public health in Australia with respect to the major diet-related diseases by the identification and substantiation of foods with defined health benefits.