The diet is tailored to fit the demands of your particular genetic blueprint, and if you follow it faithfully, it will optimise your health physically and mentally, and to some extent defer the onset of any disease or illness you may be prone to.

This is nutrigenomics, or nutritional genomics, the science of how nutrients in food affect gene expression - in other words, how your genes behave in response to what you eat and drink - and how you can create a diet to match your gene profile.

It's well known that nutrition affects people on a daily basis in both health and disease, and for decades health researchers have been analysing these dynamics and developing a failsafe means of applying their findings to the benefit of individual health.

Essentially, nutrigenomics has found that, when we eat a meal, much more is happening than the food being metabolised to provide energy. Some dietary chemicals change and bind to proteins that "turn on'" or "turn off" certain genes, and depending on that outcome, we're thriving or just surviving.

But the day that nutrigenomics can be practically applied has not arrived yet, and experts in the field are divided about when it will be. "Current evidence shows that nutritional genomics is in its early developmental stages, and any personalised dietary advice is premature," says Celeste Naude, researcher and dietician at Stellenbosch University's Division of Human Nutrition.

"Health professionals and dieticians should provide only evidence-based nutrition and lifestyle advice. More personalised advice will be incorporated as it becomes clinically applicable and safe in the future."

Nutrigenomics specialist and Cape-based dietician Yael .loffe does not agree. "There are a limited number of genes that have alreadybeen well researched, and it is definitely not too early for some types of genetic testing and advice, done by those with a good understanding of the science," she says.

So. while your fish, fruits, veggies, selenium supplements, olive oil. whole grains, lower fat dairy, lean meats, healthy fats, etc. remain tried and tested health solutions, in time your dietician will have a clearer idea of exactly what to combine and in what quantity.

The appeal of nutrigenomics is undeniable, and will make a difference to millions of lives when it does mature, but Naude is quick to point out that there are many variables in determining how nutrients influence genes on a molecular level, which makes this science highly challenging.

"Although researchers are making great progress towards gaining a comprehensive understanding of individual gene variations and their associations with nutrition and lifestyle, more work remains to be done in order to understand how individual genes interact with each other.

"The picture is not complete, and analysing a few gene variants and ignoring other possible interactions may result in incomplete analysis and the possibility of misguided interventions," she says.

In the meantime, though, people's DNA is being analysed to give medical professionals an insight into the risk of patients developing chronic diseases.

In Joburg. it is being done by a company called DNAlysis Biotechnology, and involves a quick and painless scraping from the inside of the cheek, then a batten- of tests to determine a predisposition to conditions like heart and cardiovascular disease, osteoporosis, thrombotic diseases, diabetes, inflammatory disorders, obesity, anti-oxidation and detoxification disorder - as well as breast, prostate and colon cancer.

"After about two weeks, the patient gets what is called a "disease predisposition report' from their doctor that identifies his or her specific gene variants, a risk profile as well as dietary and lifestyle recommendations," explains Dr Daniel Meyersfeld, co-founder of DNAlysis.

 "Once patients know that their genetic make-up exposes them to a higher risk of developing a severe chronic disease, they are more likely to make the right lifestyle choices to combat it, including steps like drinking less alcohol, quitting smoking, adjusting their diet and exercising more regularly," he says.

Meyersfeld is quick to add that these tests are not yet sufficiently advanced to be taken in isolation. but are a highly useful tool that can supplement traditional medical interventions.

"The more insight that a healthcare professional can gain into the risks that their patients face, the better for all concerned." he says.
 
But Naude warns: "Premature use of gene profiling increases the risks of consumers being misled, especially when companies link the results to the sale of unproven and overpriced supplements."

As with nutrigenomics, the benefits of gene profiling have farreaching potential, considering the increasing cost to the economy as a result of avoidable disease.

South Africa is afflicted by a massive burden of multiple diseases, with cardiovascular disease, diabetes and certain cancers causing the greatest concern.

"The early identification of highrisk individuals, and the implementation of appropriate management programmes and recommended lifestyle modifications can go a long way to delaying or preventing onset of disease as well as improving people's health." Meyersfeld concludes.

Of course, as Naude points out, most of the recommended remedies following your genetic test will be what you've already been advised, such as stopping smoking, losing weight and more exercise.

So keep the fridge stocked with veggies, and keep those feet moving.