Nutrigenomics, or nutritional genomics, is the study of genes and nutrition. More specifically, it focuses on understanding how a person’s DNA responds to the foods they eat. And how to use this knowledge of genes to tailor a diet to help individuals reach their health goals, whether it’s weight loss, athletic performance, or disease prevention. However, some experts criticize the study of nutrigenomics, seeing it as a new health trend marketed as a custom-made, “perfect” diet to solve personal health issues.
What is Nutrigenomics?
Taking the implications aside, let’s focus on the science found so far. Molecular biologist Monica Dus studies the interactions of food, genes, and the brain. She explains nutrigenomics as a communication, as food “talks” to the genome. This message could impact physiology, longevity, and health. Although this is a new field of research, scientists have already learned a lot, namely that the relationship between food and individual bodies is more complex than we’ve once thought. 
It may sound remarkable that food’s “messages” to the genome could affect people’s biology. But researchers have found a practical example of this implementation in the humble beehive. Worker bees live for only a few weeks, don’t procreate, and work constantly. Meanwhile, the queen bee can live for years and she’s able to birth the entire colony.
So how could two creatures with the same genes have such different abilities and lifespans? The answer is food. Worker bees eat pollen and nectar while the queen eats royal jelly, a secretion eaten by all larvae in the colony, but only the ones chosen to be queens continue to eat it for the rest of their lives. It provides them with the necessary development to fulfill the role of the queen bee. In other words, the nutrients “tell” the bees’ bodies to turn into the physiology and anatomy of a queen bee.
How is this possible? It all comes down to the compounds in food, including macronutrients (protein, fat, and carbohydrates) and micronutrients (vitamins and minerals). These compounds can trigger certain switches in the genome during digestion. These genetic switches can decide how much the body produces a certain gene product.
For instance, byproducts of the amino acid methionine can turn on the genetic switch for cell growth and division. And vitamin C protects the genome from oxidative damage. In short, foods can flip genetic switches to influence individuals’ health and wellness. (Although these tests have only been conducted in animal models, like bees, and not on humans as of yet.)
“You are what you eat”
“One interesting aspect of thinking of food as a type of biological information is that it gives new meaning to the idea of a food chain,” writes Dus on The Conversation. “Indeed, if our bodies are influenced by what we have eaten – down to a molecular level – then what the food we consume ‘ate’ also could affect our genome.” Take, for instance, milk from grass-fed cows and grain-fed cows would provide people with different amounts and types of fatty acids and vitamins, and thereby, different nutritional messages for their genomes.
“Scientists have only recently begun decoding these genetic food messages and their role in health and disease,” concludes Du. “We researchers still don’t know precisely how nutrients act on genetic switches, what their rules of communication are and how the diets of past generations influence their progeny. Many of these studies have so far been done only in animal models, and much remains to be worked out about what the interactions between food and genes mean for humans.”
As of now, people interested in eating based on their genetics can work with nutrigenomics-specialized dieticians to craft an individualized meal plan. It starts with a simple cheek swab and then the dietician explains what the results mean. For instance, if someone has the genetic variant linked with high levels of triglyceride, a certain kind of fat in the blood, a dietician could suggest eating more omega-3 fatty acids, which reduce triglyceride levels.
The test may also indicate if someone has the potential to develop high blood pressure or cholesterol, crave sugar, and get jittery after consuming caffeine, and a dietician could help navigate these issues before they occur. It may also show if someone can burn more calories through cardio or strength training. 
The Controversy Surrounding Nutrigenomics
However, there is an ongoing debate on this topic and if it’s a relevant field of study. Jonathan Jarry M.Sc. voices his concern on McGill, where he considers nutrigenomics to be overhyped as a potential diet of the future. For one, these genetic tests cannot predict if people actually would get diseases like cancer or diabetes. Jarry explains that as of now, many people are not eating enough fruits and vegetables, not exercising enough, and not getting enough sleep. “Improving these statistics does not require scrutinizing someone’s genes, but rather embracing well-known and universal health recommendations,” he writes.
He argues that even with accurate test results, information doesn’t necessarily cause a change in behavior. People are aware that eating junk food isn’t good for their health, but that doesn’t stop them. Would they respond so differently to a genetic test? “For most of us, food is not just fuel; it’s a social activity,” writes Jarry. “We know that people choose what to eat based on convenience, appearance, price, taste, and social engagement, with health considerations further down the queue.” 
Changing our behavior is difficult, no matter how tailor-made our recommendations are. Although nutrigenomics can teach us a lot about how food affects us, it remains to be seen if it leads to improved health for people on a large scale.
- “What you eat can reprogram your genes – an expert explains the emerging science of nutrigenomics.” The Conversation. Monica Dus. March 1, 2022
- “How Nutrigenomics May Impact the Way You Eat.” Cleveland Clinic. May 10, 2022
- “The Yummy Hype of Nutrigenomics.” McGill. Jonathan Jarry M.Sc. September 2, 2022