Study Spotlight Take-Away with Chef Dr. Mike
Genetics of Vegetarianism: A Genome-Wide Association Study
Almost everyone is aware of the effect that dietary choices can have on our jeans expression. The Standard American Diet, or SAD, is correlated with an ever-increasing waistline and an increased risk of developing a plethora. of diet-related diseases such as obesity, type II diabetes, cardiovascular disease, and many others.
But what about our genes’ effect on our dietary preferences? To a certain extent, are we predetermined to favor a particular dietary preference?
We know this is true on the surface and at the extremes by simply examining significant food allergies. A bag of peanuts can help deliciously sustain one individual yet be fatal to another human being.
A significant body of research suggests an important heritable component in our dietary preferences. A recent study probed the connection between dietary preferences – in this case, vegetarianism – and a particular genetic profile.
The Study:
- Enrolled UK biobank participants consisting of 329,455 controls and 5324 individuals identified as strict vegetarians (approximately 1.6% of the study population). This agrees with the existing data estimating that about 2.3% of adults in the UK identify as vegetarian[1].
- Dietary analysis consisted of multiple dietary questionnaires and multiple 24-hour dietary recall surveys.
- Vegetarianism cases were defined as individuals who did not consume any animal flesh (including beef, lamb, pork, poultry, fish, and other seafood) or products derived from animal flesh, such as lard, for at least one year.
- Genetic analysis searched a dataset consisting of 93,095,623 autosomal single nucleotide polymorphisms (SNPs).
The Take-Away:
- Vegetarians were statistically more likely to be younger women with a lower BMI and a higher Townsend deprivation index (lower socioeconomic status). This finding is in agreement with previous studies comparing vegetarians to non-vegetarians.
- At the genome-wide significance threshold, one particular SNP on chromosome 18, rs72884519, was found to be highly significant (P= 4.997×10-8).
- This correlated to the involvement of four specific genes, RIOK3, NPC1, RMC1 (C18orf8), and TMEM241, as highly relevant in terms of individuals choosing a vegetarian diet, with a total of 34 genes possibly involved in the process.
- NPC1 (NPC Intracellular Cholesterol Transporter 1) encodes a large protein that resides in the membrane of endosomes and lysosomes and mediates intracellular trafficking of cholesterol and glycolipids.
- Mutations in NPC1 are responsible for 95% of Niemann-Pick disease type C cases, a lysosomal storage disease characterized by intracellular accumulation of cholesterol and glycosphingolipids in various tissues, with progressive neurological disease being the most significant clinical manifestation.
- These findings and others suggest that the genetic contribution to vegetarianism may be related to lipid metabolism and its role in brain function.
- The mechanisms by which genetic variants influence dietary choices may involve an interplay between metabolism, physiologic effects, and individual taste perception.
The Caveats:
- Although numerous studies suggest a significant genetic influence on the food choices we make, food choice is a complex process that also incorporates Cultural and Social Influences and Factors, Nutritional Knowledge Awareness, Baseline Health, Weight-related Goals, Convenience and Accessibility, Economic Factors, Psychological and Emotional Factors, Food Advertising and Marketing Influences, Food Availability and Variety, Ethical and Environmental Concerns, Culinary Skills and Cooking Abilities, and Peer and Family Influences.
- This study was limited to a Caucasian population to avoid compounding by ethnicity.
- The study data relied on self-reporting.
It is also important to appreciate that gene expression is not written in stone. This study helps to highlight the dual nature of how our genes influence our choices, how our environment can influence our genetic expression, and ultimately, how this interplay delivers health and wellness or disability and disease.
[1] The number of actual strict vegetarians is likely lower as multiple studies have suggested that between 48-64% of self-identified vegetarians report consuming fish, poultry, and/or red meat.
The Study: Yaseen NR, Barnes CLK, Sun L, Takeda A, Rice JP (2023) Genetics of vegetarianism: A genome-wide association study. PLoS ONE 18(10): e0291305. https://doi.org/10.1371/journal.pone.0291305.
