If there’s one thing the last several decades of nutrition research have proven, it’s that there’s no one-size-fits-all diet. While many factors are at play, one reason certain eating plans work for one person but not another may have to do with our genetics.
Nutrigenomics is a fascinating, up-and-coming field that uses genetic testing to determine the interplay between genes, nutrition, and health. This information is used to help pinpoint the ideal diet for each individual.
Here’s a look at what nutrigenomics is, what you can expect if you try it, and how it might shape the future of personalized nutrition.
“Nutrigenomics is the study of the relationship between genomics, nutrition, and health,” says geneticist Jan Lim, MS, of CRI Genetics. “The field includes both the study of how the whole body responds to micro- and macronutrients, as well as the relationship between single genes and single gene/food compound interactions.”
You may sometimes hear this field referred to as “nutrigenetics.”
Technically, nutrigenomics refers to how nutrients influence your body to express genes, while nutrigenetics refers to how your body responds to nutrients because of your existing genetic makeup. However, many people use the terms interchangeably.
Though the science of nutrition genetics is still in its infancy, the idea that our genes can determine our best diet isn’t as space-age as it might seem.
In fact, as far back as the early 20th century, British physician Archibald Garrod is credited with establishing a connection between nutrition, genetics, and phenotype.
The Human Genome Project of the 1990s, which mapped out human DNA, paved the way for the modern era of nutrigenomics. Since then, hundreds of studies have examined genes’ influence on the body’s response to diet, as well as the other way around.
Today, it’s not uncommon for practitioners like dietitians and doctors to use genetic testing to assess patients’ dietary needs and set customized health goals.
Genetic testing as part of nutrition counseling might sound rather extreme. A genetic workup just to see if you should eat low carb or get more vitamin C?
However, as part of an integrative nutrition approach, nutrigenomics can shed light on issues a simple health history can’t. This includes everything from a predisposition to heart disease to why you’re not losing weight when you’ve tried everything.
“Genomic testing truly is useful for anyone wanting to be proactive about their health,” says dietitian and certified genomic medical clinician Andrea Chernus, MS, RD, CGMC. “Genomic testing can help to explain why situations exist for a patient, such as which style of eating might suit them best.”
By looking at your genetic makeup, a practitioner may be able to advise you on certain eating patterns that will or won’t work well for you. For example, gene variants might mean your body wouldn’t benefit from a vegan diet or wouldn’t adapt well to a keto diet due to genomic tendencies for fat metabolism.
A nutrigenomic test can even uncover your personal best sources of both macro- and micronutrients.
Perhaps your body is unable to optimally use omega-3 fatty acids from plant sources, or you have trouble converting sunshine into vitamin D. With this data, a trained practitioner can instruct you on which foods to eat or supplements to take to meet your needs.
Likewise, predispositions toward certain diseases may show up on a nutrigenomics test.
“We may be able to see gene variants that increase one’s risk for breast cancer due to the genes involved in estrogen metabolism, for example,” Chernus notes.
Empowered with this information, you can make preventative choices to mitigate risk through diet.
Interested in pursuing a genetic approach to nutrition, but not sure what to expect? Nutrition counseling using nutrigenomics is surprisingly painless.
“The experience should start with a detailed health questionnaire so the practitioner has a complete understanding of the patient’s health status, history, family history, and current and past lifestyles,” says Chernus. “The actual test involves an at-home cheek swab. It’s typical for a test to evaluate anywhere from 80 to 150 or more genes. It’s quite simple to do.”
In some cases, if your results raise additional questions, a blood test may follow.
Once your test results are back, your dietitian or other health professional will evaluate them and work with you to develop an action plan for eating.
Although extensive research has been conducted on the connection between genetics, diet, and health, the science of nutrigenomics is still emerging. “Nutrigenomics is a relatively new field of research, so we still have a lot to learn,” says Lim.
This isn’t to say that genetics aren’t a helpful piece of the puzzle when it comes to nutrition counseling. Just recognize that nutrigenomics won’t solve every diet conundrum, and that genes are just one of many factors that influence health and ideal dietary choices.
“Genomic testing should not be the sole criteria used to make recommendations,” says Chernus. “We need to include lifestyle, health history, health status, personal preferences, cultural identity, willingness of the patient to change, and their own health goals in our work.”
The availability of direct-to-consumer genetic testing for diet purposes, while it may seem exciting and convenient, is another potential drawback.
“The main drawback [of these tests] is that they’re not interpreted by a skilled clinician,” Chernus says. “Skilled practitioners use a polygenic approach: how all of the genes are part of bigger systems in the body. They interpret how these systems work together in the totality of one’s health.”
To understand the relationship between your own genome and diet, it’s always best to consult with a health professional who specializes in nutrition genetics.
“Every body is different” isn’t just true of our shape or physical type. It’s true down to the genetic level. Although nutrigenomics is a relatively new field that’s still gaining mainstream acceptance, many nutrition experts believe it’s the future of dietary counseling.
As part of a comprehensive nutrition philosophy that looks at the whole person, nutrigenomics could help people overcome health obstacles other approaches can’t.
“The more personalized our approach, the better the outcome,” says Chernus.
Sarah Garone, NDTR, is a nutritionist, freelance health writer, and food blogger. She lives with her husband and three children in Mesa, Arizona. Find her sharing down-to-earth health and nutrition info and (mostly) healthy recipes at A Love Letter to Food.