Imagine a diet customised to reduce your risk of disease, or to allow you to lose weight more easily. Nutrigenetics sounds promising – but it pays to do your homework.You may have seen recent headlines about ‘designer diets’ based on the new science of nutrigenetics.
For the first time, scientists are able to conduct tests to see how our genes influence our bodies’ response to the foods we eat.
“Individuals can have very different needs based on how ‘efficiently’ their genes process those nutrients,” says Dr Flavia Fayet Moore, who is director of operations for Nutrigenomix Australia, a nutrigenetic testing company.
For example, people who have one particular gene variant need almost double the recommended daily amount of long-chain omega-3 to help lower high blood fats, which is a risk factor for heart disease. A genetic sensitivity to sodium could put you at greater risk of high blood pressure; and a genetic variation that causes some people to break down caffeine more slowly can also increase the risk of heart disease.
Nutrigenetics could also aid weight loss, says nutrigenetics expert Professor Lynnette Ferguson from the University of Auckland. For example, if a test finds you have a specific variant of the FTO gene, which affects your ability to feel full, your dietitian can then advise you on how to better manage your hunger levels.
These new genetic insights challenge the one-size-fits-all approach of the current dietary guidelines. “What we see as a ‘general healthy diet’ may not be as healthy as we think for many of us,” says Ferguson. Nutrigenetic tests “empower individuals to make more informed dietary choices,” adds Fayet Moore.
So should we all include the simple saliva swab in our next health check-up? There are a few factors to consider.
For starters, only a small number of health professionals currently offer nutrigenetic testing. Also, privacy advocates are worried about who might have access to genetic information (health insurers are one example).
HFG dietitian Zoe Wilson adds: “Some people, concerned about future health problems, could be easy targets for food and supplements marketers.”
And Fayet Moore says, “although a diet tailored to our genes that optimises weight loss would be very appealing, the science is just not there yet.”
Nutrigenetic testing costs around $300–$400 and, in Australia, is only available via healthcare professionals like dietitians or GPs. Because there are so many factors involved in health and disease, it’s important that an expert puts the test results into context. In the US, where companies can sell tests directly to consumers, some companies have been accused of providing medically unproven advice and misleading consumers into buying overpriced supplements.
“We should be optimistic about nutrigenetics, but cautious about jumping the gun,” says Wilson. For more info, find a dietitian near you at www.daa.asn.au.