Being A Vegetarian May Be Up To Your Genes

Cutting back on meat seems to be in vogue for many people, Meatless Mondays are becoming popular around the world, and that really isn’t a bad thing. Going completely meat-free permanently can prove to be difficult for many people, and this peer-reviewed study published in the journal PLOS ONE suggests that a person’s genetic makeup plays a role in determining whether a person can adhere to a strictly vegetarian diet. 

Even though becoming a “vegetarian” is becoming increasingly popular, this lifestyle remains a small minority of people around the world. In the UK around 2.3% of adults and 1.9% of children are vegetarian. In America around 3-4% of the population are vegetarian, and as it turns out there is a reason why many people are not able to give up meat. 

"Are all humans capable of subsisting long-term on a strict vegetarian diet? This is a question that has not been seriously studied," said corresponding study author Dr. Nabeel Yaseen, professor emeritus of pathology at Northwestern University Feinberg School of Medicine.

According to the researchers, a large proportion of self-identified vegetarians, about 48-64%, report eating fish, poultry, and/or red meat, which suggests that environmental or biological constraints override the person’s desire and will to follow a true vegetarian diet that contains no meat.

"It seems there are more people who would like to be vegetarian than actually are, and we think it's because there is something hard-wired here that people may be missing."

To investigate whether genetics contribute to the ability to adhere to a true vegetarian diet the researchers compared UKbiobank genetic data from 5,324 true strict vegetarians to 329,455 controls. All of the participants were Caucasian in order to attain a homogeneous sample and avoid confounding by ethnicity. The analysis identified three genes that were significantly associated with vegetarianism as well as another 31 genes that are potentially associated. Several of these genes are involved in lipid metabolism and/or brain function, according to the researchers.

"One area in which plant products differ from meat is complex lipids," Yaseen said. "My speculation is there may be lipid component(s) present in meat that some people need. And maybe people whose genetics favor vegetarianism are able to synthesize these components endogenously. However, at this time, this is mere speculation and much more work needs to be done to understand the physiology of vegetarianism."

"I think with meat, there's something similar," Yaseen said. "Perhaps you have a certain component -- I'm speculating a lipid component -- that makes you need it and crave it."

"While religious and moral considerations certainly play a major role in the motivation to adopt a vegetarian diet, our data suggest that the ability to adhere to such a diet is constrained by genetics," Yaseen said. "We hope that future studies will lead to a better understanding of the physiologic differences between vegetarians and non-vegetarians, thus enabling us to provide personalized dietary recommendations and to produce better meat substitutes."