Nutrition science, like the science of healthcare overall, is evolving into a new era of precision medicine, defined by the White House’s 2015 Precision Medicine Initiative as a future that “will enable healthcare providers to tailor treatment and prevention strategies to people’s unique characteristics, including their genome sequence, microbiome composition, health history, lifestyle, and diet.”
You Really Are What You Eat
Within the broad field of precision medicine is a branch of study called “nutrigenomics,” defined by Nature, the International Journal of Science, as “the study of the effects of food and food constituents on gene expression, and how genetic variations affect the nutritional environment.“
Nutrigenomics focuses on understanding “how specific nutrients or dietary regimes may affect human health,” meaning, in short, how what you eat affects your individual genetic makeup, which, in turn, affects your overall health and wellness. And, of course, we are all uniquely different in this regard.
Notions regarding one-size-fits all diets and food pyramids for better health are on the cusp of change. This has brought an increased level of important questions for nutritionists and dieticians to answer about modern day genetic-oriented developments and innovations, such as the proliferation of direct-to-consumer (DTC) nutrigenomic tests that claim to provide valid and authoritative diet advice based on your genes.
Are such tests really on target? Can you trust the results from any of the new DTC nutrigenomic test providers that are now available to anyone for fees ranging from $250 to $350? The jury is still out, with medical professionals strongly for and strongly against DTC nutrigenomic testing.
In a recent opinion piece in the New York Times, Eric Topol, a cardiologist, professor of molecular medicine and vice president of Scripps Research, writes that a universal diet is “both biologically and physiologically implausible: It contradicts the remarkable heterogeneity of human metabolism, microbiome and environment, to name just a few of the dimensions that make each of us unique. A good diet, it turns out, has to be individualized.”
He adds that DTC nutrigenomic tests that provide individualized diet advice based on identifying parts of your genome garnered through a saliva sample “don’t have the data to back their theory up.” Does that mean you should not get a nutrigenomic test?
Veteran nutrition expert Jeffrey Bland, PhD, thinks you should get one. Bland is an organic chemist who has worked in the field for more than 35 years. He is a Fellow of both the American College of Nutrition, where he is a Certified Nutrition Specialist, and the Association for Clinical Biochemistry. Among his numerous academic and business accomplishments, he has authored five books on nutritional medicine for healthcare professionals and six books on nutrition and health for the general public, including his latest published in 2014, “The Disease Delusion: Conquering the Causes of Chronic Illness for a Healthier, Longer, and Happier Life.”
Bland believes that getting a nutrigenomic test is really a personal decision based on one’s feelings and beliefs about the science available to us today and into the future. He says that at some level the future of nutrigenomics is now, and at another level the future is off in the distance difficult to fully prognosticate but seemingly on the verge of coming into fruition soon.
“Does a person want to be an early adopter of this rapidly emerging new concept?” he asks. Or, “do they want to wait until stuff is more crystallized and we have done more boundary analysis to know what the strengths and weaknesses are?”
There are some facts that point toward getting a nutrigenomic test now. For example, a genotype, meaning, in this case, a specific gene inherent to certain individuals, but not all, identified as CYP1A2, can be associated with coffee intake. That genetic marker “helps us understand if caffeine is good for us or harmful,” writes Ahmed El-Sohemy, PhD. Canada Research Chair in Nutrigenomics, University of Toronto, via email communication. “We showed that individuals who are slow metabolizers of caffeine have an increased risk of heart disease, whereas fast metabolizers see the opposite effect. They may actually benefit. More recently we showed that athletes who are fast metabolizers benefit more from the performance-enhancing effects of caffeine.”
El-Sohemy mentions another genetic marker identified as GSTT1. “Having a particular version of this gene means your vitamin C requirements differ. The risk variant of this gene is found in about 20% of Caucasians, but about 50% of East Asians.”
El-Sohemy founded Nutrigenomix Inc. in 2011 — known as the first genetic testing company for personalized nutrition that developed a genetic test to be used exclusively by health professionals. “This differs from other companies who sell their test direct to consumers,” he explains. Nutrigenomix currently claims to be tied into 8,000 healthcare professionals in 35 countries who are authorized providers, one of which is the Cleveland Clinic, where consumers pay $249 for a test-kit directly from Nurtrigenomix and then wait 3 to 6 weeks for a Cleveland Clinic Coordinator to obtain test results. Customers are then set up with a dietician who goes over their results in a 1-hour office visit for an additional cost of $95.
Bland points to another type of personalized nutrition test from a company called DayTwo that sequences the DNA of people’s digestive system microbiomes (genetic materials of microorganisms) related to blood sugar control. “We now know those families of genes connected into our microbiome and how this complexity of our gut bacteria can influence how our genes and the cells of our body express themselves and do their work,” Bland says. “Companies like DayTwo analyze the tendency of foods to produce alterations in blood sugar, not based on the genes of our body but by the genetic profiling of our microbiome.”
In this scenario, customers fill out a health questionnaire and dish out $349 for a stool sample kit. As noted on the DayTwo website, the company uses “a scoring system to rate thousands of different foods and food combinations based on your biometrics, gut microbiome analysis, lifestyle factors and health questionnaire — which yield a unique nutrition profile that enables blood-sugar balance.”
Be Aware of All the Hype
Overall, there are numerous providers of nutrigenomic testing services, making it difficult to choose. In an August 2018 article by Dr. Bertalan Meskó, director of The Medical Futurist Institute based in Budapest, Hungary, he explains that “the constant flux of the nutrigenomic market, the tendency to overhype the technology and the scarcity of hard scientific evidence make it difficult to give a precise overview of the industry.” Meskó’s article included information that brings more questions than answers about several existing DTC nutrigenomic testing companies.
Regardless of any kind of genetic test a consumer might be considering, the U.S. National Library of Medicine’s website on genetics has a section on how to choose a DTC testing company, including a list of what information they recommend is needed in order to make a wise decision, such as:
- Does the DTC testing company have a professional-looking website with adequate information about its services?
- Are experienced genetics professionals on the company’s staff, and do they offer a consultation with such professionals?
- Does the company explain which genetic variations it is testing for, as well as include scientific evidence linking those variations with a particular disease or trait?
- What kind of laboratory does the testing? Where is it located, and is it certified and meet Clinical Laboratory Improvement Amendments (CLIA) U.S. federal regulatory standards?
- Does the company explain how it protects your privacy, as well as who will have access to your data and how it may be shared?
Just Do It May Apply
At the end of the day, Bland believes that “everyone should have their genes analyzed, because I think it introduces you to the most important thing that we own, which is our book of life in a very intimate way,” he says. “It tells you a little bit about your uniqueness and helps you to better navigate through your life, knowing that life is uncertain. But what we want to do is to make things more certain, if possible, so we can make intelligent decisions. That is where I think we are with nutritional genomics today. “