DNA reveals the best diet for you
WHEN Michael Fenech sits down to dinner, he looks at the food on his plate rather differently to the rest of us. For Fenech, a principal researcher with the CSIRO’s Human Nutrition centre in Adelaide, tasty morsels of meat and vegetables are more than just fuel to keep his body running. They also contain nutrients that have the potential to protect his DNA from serious damage, and affect his chances of falling ill.
Fenech has spent the past 20 years studying the nutrients we need to keep our genes healthy, and how our genetic makeup influences the way we respond to food.
That work has put him at the forefront of a new scientific discipline known as nutrigenomics’’, which brings to bear a detailed understanding of how humans differ from one another in genetic terms and applies it to the traditional science of nutrition.
It’s also a field that’s poised to take on growing importance given the recent political emphasis on preventive’’ health care, as highlighted in this week’s federal budget. Advocates say nutrigenomics could allow us to tailor our diets to our individual genetic characteristics — potentially helping us lose weight more effectively, avoid cancer, say goodbye to binge drinking and live to a ripe old age.
Folate — vitamin found in leafy vegetables, fortified grain products and other foods — is a good example of how nutrients can affect our genes, Fenech says.
When one has inadequate intake of folate, the DNA in the cells can be damaged, or fragmented, or the expression of the genes can be altered,’’ he says. This can have a dramatic effect on our chromosomes, causing as much damage as carcinogenic doses of radiation.
Similar damage may result from deficiencies in other nutrients such as calcium, magnesium, retinol, nicotinic acid, vitamin E and vitamin B12, adds Fenech.
And as our cells grow and divide the damage can accumulate, a problem associated with infertility, developmental defects in the foetus, cancer, Alzheimer’s disease and other conditions.
But avoiding these unhealthy outcomes is not a simple matter of everyone boosting their nutrient intake a certain amount, Fenech says. Each of us carries within our cells different forms of genes that affect how our bodies absorb and use the nutrients we need, such as folate and vitamin B12.
At this point in time, we’re assuming that the nutritional requirements are the same for everyone and that everyone absorbs the nutrients in the same way — well, that’s not the case.’’
Fenech’s work is giving us an important insight into the detailed mechanics of how good dietary choices keep us healthy, says nutritionist Rosemary Stanton. Michael