Can having your DNA tested lead you to live a healthier life?

From a blood test to a stool analysis, measuring biochemical markers is a time-honoured way to assess health and enable prognosis and treatment. Whether it’s taking your temperature (with a thermometer or a maternal palm) to more serious investigation, we are all familiar with the implication of raised levels of this or that.

Mostly we are taught to fear the numbers and take steps to bring them back into line with a combination of lifestyle changes and medication so that whatever it is returns to acceptable levels. Achieving success comes with a sense of satisfaction and is, of course, the responsible thing to do — after all, who would purposefully put themselves in a high-risk group for a life-changing or life-limiting event?

Yet what about the things that we can’t change, such as DNA — is that worth testing and, if so, what do you do with the results?

The move towards preventative health continues to gather pace. The focus on the self includes personalising health care, and what could be more personal that having one’s DNA assessed? DNA testing has become more mainstream over the past decade and there are several companies offering advice based on the outcome of what has to be the ultimate selfie. However, DNA interpretation is unregulated and arguably immature, and the methods used to interpret the results and how they apply to day-to-day lifestyle are unproven.

To test my DNA I chose the company iamYiam. All it requires from me are a few spits of saliva and responses to a detailed questionnaire. These are matched to extensive research studies — 170,000 papers, the company says — to deliver a personalised activity and nutritional plan tailored to your health goal (I chose weight loss). Two weeks on and I am looking at the results online, which, according to iamYiam founder Lorena Puica, are ‘probabilistic’.

In practical terms this means that suggestions are made rather than direct advice given. For example, a large percentage of people with the MCM6 gene and a specific single nucleotide polymorphism (SNP, or snip) are lactose intolerant. If you possess both these risk factors it is possible, if not probable, that you are intolerant to the disaccharide in milk. It turns out that I do have these risk factors, and so should probably give up my Greek yoghurt and the frothy milk in my coffee, although I see no physical signs of any intolerance.

My own results confirmed much of what I already know from experience, but seeing this borne out genetically was quite comforting. For example, it is probable for me to gain weight easily, be lactose intolerant and process caffeine slowly. In addition it is probable that I don’t process dietary fats or protein well, which may mean that I require increased levels in the diet. There is a section for nutrients too, and iamYiam suggests that I need a diet rich in, for example, vitamins B6, B12, C as well as iron (so extra incentive for me to eat wholegrains, red meat, fruit, vegetables and legumes).

Extrapolating that information, one could hypothesise that I am more likely to experience conditions associated with low intake of said nutrients, which are numerous. I found this especially interesting and, although I’d like to think my diet was quite good in the first place, I have made some changes. In time DNA will probably be used to create specific supplements tailored to personal profiles.

The website also offers suggestions about health conditions I might be aware of, in my case heart disease. There’s more in the fitness section as they suggest that my gene profile makes it likely that I am not flexible, prone to muscle injury and should ensure that I undertake endurance exercise. Interestingly, my experience confirms that all three are true, and made me aware, once more, that I really should be doing some cardio exercise, not just weight training.

The results finish off with a handy summary of one’s genetic strengths and weaknesses, like a school report gently suggesting that I try harder.

You can choose to see a nutritionist about the results to help you take action and the site also suggests specific supplements as well. Given that the test costs £387, I wonder how many people will spend more money on private sessions? (23andMe, already trialled on this site, advertise theirs at £149, while DNAFit’s range from £99 to £249 depending on whether you want diet and/or exercise reports.)

I suppose that the results of a DNA test could be extrapolated to allow very direct advice. In my experience, someone is more likely to take action if that advice feels very personal. But the sort of advice we’d really like, such as ‘eat this vegetable, not that one’, ‘have X per cent of this grain combined with that protein’ and ‘drink so many litres of water a day’ are a way off.

That said, the results do feel personal, and are likely to motivate one more than general health directives such as five-a-day. Since getting them I have paid more attention to my diet, so one could easily argue that it’s money well spent.