Nutrigenomics: How Your Genes Influence Your Ideal Diet

It has long been debated whether the forces of “nature” or those of “nurture” are the determining factors in our health and our ultimate fate. Nature is represented by our genetics, what we are born with. Nurture is the environment in which we live and the decisions we make on a daily basis.

What we know today is that neither nature nor nurture can explain many of the molecular processes that ultimately govern human health.

In fact, having a gene that predisposes you to a disease is not predictive of your risk for that disease, in and of itself. Rather, it is the unique interplay between those genes and your environment that will tip the scale in favor of disease… or health.

And, arguably, no other environmental factor has a greater influence on how your genetics are expressed than your diet.

Nutrigenomics: Control Your Genes… with Food!

Human studies show that macronutrients (fats and proteins), micronutrients (vitamins and minerals), and phytochemicals (such as flavonoids and carotenoids) and zoonutrients (like EPA and DHA) impact how genes express themselves.

The foods we consume “program” our genes to do a wide number of things, including determining proper hormonal balance to regulating immune function… promoting detoxification… and directing the body how to use nutrients for fuel and growth.[i]

Food is not only fuel. It is information. It communicates with your genes to create conditions of wellness or illness… of weight gain or loss. By the same account, your individual genetics also has an influence on what is the best diet… for YOU.

The field of study of how our diet influences our genes is called nutrigenomics.

The primary focus of nutrigenomics to date has been on single-nucleotide polymorphisms (SNPs) – small variations in DNA sequence that account for 90% of all human genetic variation. Your SNPs can alter the function of your genes, influence metabolism, dictate how we break down and utilize carbohydrates, proteins, fats and alcohol and much, much more.

Research shows these small genetic variations can have a big impact on your nutritional requirements… and therefore your ideal personalized diet. Take a look at these common SNPs and how they impact your ideal diet…

Lactose Intolerance: Roughly 65% of the human population has a reduced ability to digest lactose after infancy. This is due to a mutation in the LCT gene that causes people to gradually lose lactase (the enzyme required to break down milk). Lactose intolerance in adulthood is most common in people of East Asian descent, affecting more than 90% of adults in some of these communities. It is also very common in people of West African, Arab, Jewish, Greek, and Italian descent.[ii][iii]
Amylase Gene: For early humans, tubers and roots were an essential staple in lean times. To digest these starches, an enzyme called amylase is required. But the salivary amylase gene (AMY1) varies among individuals, impacting one’s ability to effectively digest starch. Not only does the number of copies of this gene correlate with amount of amylase produced… it also correlates to the starch content of your ancestor’s traditional diet.[iv] Fewer copies of this gene? Eat fewer carbs. More copies, you can likely tolerate more high-quality carbohydrates, like root veggies and winter squash.
Favism: A deficiency in glucose-6-phosphate dehydrogenase (G6PD) causes a toxic reaction to fava beans. While detrimental for eating fava beans, this deficiency appears to confer protection against malaria. [v]
Grain Digestion: Ancestral cultures who consumed a grain-rich diet are more likely to have a “hyperactive” version of PLPR2 – an enzyme responsible for breaking down plant glycolipids like those found in grain-based foods. [vi]
Seaweed Digestion: Research shows Japanese individuals can digest seaweed carbohydrates far more efficiently than non-Japanese. This was made possible through generations of adaptation, causing their gut flora to produce porphyranase and agrarase enzymes which degrade the polysaccharides in seaweed.[vii]
Coffee Metabolism: A gene called CYP1A2 indicates how quickly a person metabolizes coffee. If you’re a heavy coffee drinker and a slow metabolizer, you’re more likely to develop health problems like heart attacks or diabetes.[viii]
Choline Requirement: Postmenopausal women who carry the SNP for PEMT6 require more dietary choline than premenopausal women. Without additional choline (found predominantly in animal foods including egg yolks and liver) women with the SNP have a higher risk of fatty liver, liver damage and other negative health outcomes.[ix]
Folate Metabolism: An enzyme in the methyl cycle called methylene tetrahydrofolate reductase (MTHFR) is involved in folate metabolism. Which version of this gene you have impacts your requirement for B vitamins. For example, Individuals with the “CT” or “TT” genotypes have reduced enzyme efficiency (about 60% and 20% respectively) compared to the “normal” gene. This enzyme deficiency can increase levels of homocysteine (an inflammatory amino acid linked with heart disease and Alzheimer’s) when dietary intake of folate is too low. For people with MTHFR gene defects, boosting folate, vitamin B6 & B12 is important to reduce inflammation and improve detoxification.
Fat Metabolism: FTO is a protein that is associated with fat mass and obesity in both adults and children. People with the AA variant of this gene have an increased sensitivity to fats.[x]
Gluten Intolerance: While gluten has been found to promote leaky gut (even in healthy people), you may want additional clarity as to just how risky indulging in that occasional croissant really is. HLA DQ gene variations help you determine that. Having different variations of this gene is associated with increased risk for celiac disease and gluten intolerance. [xi]

And this list is just the tip of the genetic iceberg, so to speak!

You can see how the answers to many common dietary questions are encoded right in your genes.

Questions like…

Is gluten safe for me?
How much coffee can I drink?
Should I eat a high protein diet?
Can I eat dairy?
Does my body process starchy foods well?

Testing companies like 23andme or Illumina, can give you valuable insight to your unique SNPs so that you can make the best dietary choices for your personal genetic predispositions and long term health.

In my upcoming articles I’ll be discussing how diet impacts your microbiome and metabolome and the tools you can use.

ED NOTE: Kelley Herring is the co-founder of Wellness Bakeries, makers of grain-free, gluten-free, low-glycemic baking mixes for cakes, cookies, breads, pizza and much more.

Kelley’s academic background is in biology and chemistry and for the last 15+ years, she has focused on the study of nutritional biochemistry…and the proven powers of compounds in foods to heal the body.