Now that the miracle of mapping the human genome has become a mail-order affair, there are a bunch of ways you can interpret your DNA. The latest is by linking your specific genes (called nutrigenomics) to certain diets that might be better for you. The question: is the science really there yet? Do nutrition DNA tests really work? And, would it ever be appropriate to test kids for DNA-related health risks?
First, Get Your DNA Tested Completely
Doing a deeper dive into your DNA analysis is a two-step (or more) process. First, you need to get your DNA tested by a company like 23&Me or Ancestry.com. Those companies do the heavier lifting for testing. After you have your DNA profile (and possibly found even more relatives you never thought you’d want in far-flung places), other companies can use your profile for more specialized analysis. Like, say, nutrition or fitness.
Next, Send Your DNA To Another DNA Testing Site
Sites for more focused testing, like DNAFit or GenoPalate, take your DNA profile from those first testers and look for genes and alleles (gene variants) that supposedly link to various traits or likelihoods, such as caffeine sensitivity, fast-twitch vs. slow-twitch muscle types (indicates whether you might be a better sprinter than marathon runner) and a predisposition toward gluten intolerance.
GenoPalate, for instance, offers all this, using your existing DNA results, for about $40:
- The predisposition of two sensitivities.
- The metabolism rate of two substances.
- Genetic needs for 23 nutrients.
- The 85+ best foods for you.
It sounds great; indeed, it sounds like the future of health (called “precision medicine”) has finally arrived. But, don’t get too excited.
A sensitivity isn’t the same as an allergy; allergies aren’t found in genes. Plus, a predisposition doesn’t mean you’re intolerant, it only means you might have a tendency toward intolerance of that particular food. And, most living humans need the same amounts of nutrients, within a pretty narrow range.
“For me, the data isn’t definitive enough to justify the kind of marketing and pop culture noise we are seeing,” Timothy Caulfield, LLM, FRSC, FCAHS, said in Today’s Dietitician. “Not even close,”
Genetics Are Complex
Here’s the problem: there might be some evidence that, depending upon certain genetic markers, you possibly metabolize carbs or proteins differently, but there’s zero research conclusively backing up the idea that you can biohack your diet for optimal health using nutrigenomics.
“DNA is important, but it plays a pretty minor role in making personal decisions about food,” Dariush Mozaffarian, cardiologist and dean of the Friedman School of Nutrition Science and Policy at Tufts University, told NPR.
For instance, genes only explain about 5% to 10% of the risk linked to diet-related diseases such as obesity and type-2 diabetes, per Mozaffarian.
Mascha Davis, a Private Practice Registered Dietitian Nutritionist, founder of Nomadista Nutrition (and author of the upcoming book Eat Your Vitamins), says it’s possible to get some benefits, but not anything that definitive.
“Genetic tests can tell us how prone individuals are to being overweight or obese,” Davis tells Parentology. “They’re also useful for determining metabolism of certain nutrients. They show predispositions and aren’t diagnostic.”
And research doesn’t show that commercially available nutrigenomics tests work in a straightforward fashion, either. A 2015 meta-analysis in the OMICS Journal using DNA data from over a half a million subjects, found zero to very weak associations between specific genes and specific health problems. The science simply isn’t solid yet.
What About Using Nutrigenomics for Kids?
There’s already evidence that polygenic testing is going on with IVF pregnancies, but what about using DNA testing on children?
The logic could work like this: if your child’s DNA shows a predisposition toward a food sensitivity, or a possible marker for metabolizing sugar inefficiently, you could make very early dietary changes for them to achieve a healthier life.
Davis admits there are exceptions to the “no diet” rule, like if your child has an allergy. “If your child is lactose intolerant or celiac, you should be working with a doctor and dietitian.”
Otherwise, Davis says, this wouldn’t be a good idea. “Childhood nutrition is complex. Children need specific nutrients in each stage of their lives. Restricting any of those nutrients might negatively impact development. Children generally should not be on any diet.”
Do Nutrition DNA Tests Work — Sources
GenoPalate
NPR
OMICS Journal
Today’s Dietician
Mascha Davis, MPH, RDN