Being vegetarian may partly be in one’s genes, study finds

A person’s genetic makeup can play a role in determining whether they can stick to a strict vegetarian diet or not, according to a new study.

The research, published on Wednesday in the journal PLOS One, may lead to further studies on personalised dietary recommendations and the production of meat substitutes.

While a large fraction of people self-identify as mainly “vegetarians”, they also report eating fish, poultry and/or red meat, suggesting there may be environmental or biological constraints that override one’s desire to adhere to a vegetarian diet, said scientists, including those from Northwestern University in the US.

“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,” study co-author Nabeel Yaseen said.

In the study, researchers compared UK Biobank genetic data from 5,324 strict vegetarians – consuming no fish, poultry or red meat – to 329,455 controls.

Scientists found three genes linked with vegetarianism and another 31 genes that are potentially associated.

Several of these genes, according to the study, are involved in lipid (fat) metabolism and/or brain function including two of the top three (NPC1 and RMC1).

“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,” Dr Yaseen said.

“However, at this time, this is mere speculation and much more work needs to be done to understand the physiology of vegetarianism,” he said.

While vegetarianism is increasing in popularity, vegetarians remain a small minority of people worldwide, with 2.3 per cent of adults and 1.9 per cent of children in the UK identifying as vegetarian.

Scientists believe the driving factor for food and drink preference is not just taste, but also how an individual’s body metabolises it.

Citing an example, they said when trying alcohol for the first time, most people would not find it pleasurable for the first time, but develop a taste because of how alcohol is over time.

“I think with meat, there’s something similar. Perhaps you have a certain component – I’m speculating a lipid component – that makes you need it and crave it,” Dr Yaseen said.

“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,” he said.

Scientists hope future studies will lead to a better understanding of the physiologic differences between vegetarians and meat eaters.

They said such an understanding would enable personalised dietary recommendations and to produce better meat substitutes.