DNA testing for personalized diet and exercise: Is it a key or just a clue?

Can our DNA tell us what diet we should be on and how we should exercise? We know that there isn’t a “one-size-fits-all” approach. A diet and training regime might work for one person but won’t for another.

DNA however is what makes us who we are. It’s what makes us all different. It’s the reason why one of us has brown eyes and another has blue. Can it then hold the answers to reaching our genetic potential? Will it give us a key or is it just a path we can choose to walk on?

Those who’ve taken the test say it works, but a London geneticist says it’s a “complicated picture.”

Frances Quinn, winner of the Great British Bakeoff in 2013, didn’t want to guess around her fitness and nutrition anymore. She wanted to be certain that whatever she was eating and doing would give her the results she wanted to see.

Although we mostly know her from her sweets and cakes, she says she’s very health conscious.

"I've always loved my fitness and sports, but I felt I was plateauing a bit," she said. "I was just keen to sort of build some muscle."

Her regular workouts would most often include cardio training such as running, spinning or swimming. However, her personal trainer she started working with over the summer last year, suggested she would add strength training to her regime, and, he told her to decrease the amount of cardio she was doing.

Besides a shift in her training, he brought up that Frances took a DNA test to find out how her body responded to certain food groups and exercise types.

The test she took was done by DNAFit, a consumer genetics company based in the UK, that looks at how our certain genes in our DNA affect our body’s response to exercise and nutrition changes.

It published a peer-reviewed study in the “Biology of Sports” journal in June last year to see how a genetic-based training can affect an individual’s resistance-training performance.

Avi Lazarow, CEO and founder of DNAFit, said they found that “individuals who trained to their genotypes, actually had three times improvement than the ones who didn’t.”

“In the world of professional sports, that can be the difference between no medal and a gold medal.”

Olympic long jump champion Greg Rutherford has got the test done two years ago, and said the results were an important reinforcement of his and his teams’ years of trial-and-error research as to what training and nutrition his body responds best to.

“It basically proved the things I spent probably ten years developing myself with other people,” he said.

DNAFit looks at single-nucleotide polymorphisms, (SNPs) or “snips,” which are the most common type of genetic variation among people.

According to Genetic Home Reference, SNPs are often used in genetic studies to help predict an individual’s response to certain drugs, susceptibility to environmental factors such as toxins, and risk of developing certain diseases.

In this case, the company is using a number of SNPs to unlock an individual’s fitness and nutrition codes. Through a swab test, they take a number of these well-studied SNPs, and incorporate them into a genetic scoring system. Then they create a genetic profile for each individual.

There are two main areas the results provides guidance to: nutrition and fitness. It shows whether you best respond to a higher-carbohydrate diet, higher-fat diet, or get the most benefits from power or endurance training. It also points out details such as caffeine and alcohol sensitivity, lactose tolerance, vitamin needs, injury risks and recovery speed.

But, how certain are those results? Can our DNA really unlock our best potential?

Dr. Anand Saggar, genetic specialist and consultant at St George's Healthcare, says it’s a complicated picture.

He says our DNA can point us to what we might be best suited for as far as exercise, but there are other aspects that play a big role including, mental state and environment.

However, he says it’s a more relevant clue when you take the nutrition side of things, as it can tell you what you’re more allergic or intolerant to.

“There’s an increasing recognition of these different personalized variations, and I think that’s when it can be very useful,” he says. “It can tell you how your body metabolizes something, and you can identify that you’re a certain type that tends to be more allergic or intolerant of certain food substances like lactose or gluten.”

Team GB athlete Andrew Steele, who’s head of professional sport & fitness at DNAFit, sees the complexity of what they are offering and says: “It’s absolutely crucial that anyone, who’s offering customer genetics, to make it very clear that it’s only one part of the picture, but without it, you don’t have the whole picture.”

“It’s not about predicting what you can and can’t be. It’s just the case of understanding this information, so you can make better informed decisions to facilitate better change.”

I took the test to see what the truth is behind the branding.

The other two parts of the test looked at 1) my body's response to nutrition and 2) its response to certain exercise types.

Some results such as lactose intolerance, and high caffeine sensitivity were quite surprising. I have noticed uncomfortable gut symptoms after having more than a cup a of milk, but never put the picture together that it might have been due to lactose intolerance. Well, now I know.

And, as for coffee, I have noticed there as well that once I drink my espresso, it keeps me energized for many hours. I assume that's because my body metabolizes it slowly.

When it comes to fitness, it certainly reinforced what took me four years to figure out — to see what training regime my body best responds to.

So overall, it all makes sense now. The results were useful, in fact, made me more conscious about what to drink and eat, and how to train on a daily basis.