Your genetics might just help sway your veggie-eating habits, new research out Wednesday suggests. The study found a possible association between adopting a strict vegetarian diet and up to 34 different genes. Some of these genes affect brain function and how our bodies process the fats we get from our food, offering a plausible explanation for a cause-and-effect relationship, but more research will be needed to confirm and better understand this potential link.
About 4% of Americans currently identify as vegetarians, according to Gallup survey data. It’s a number that hasn’t changed much in the past two decades, though other data suggests that people generally are eating less meat than they used to. At the same time, many vegetarians will eat meat at least occasionally. A 2015 study, for instance, found that 48% of self-identified vegetarians admitted to recently eating either meat, poultry, or seafood.
The difficulty in being able to maintain this lifestyle, despite the strong moral and health motivations that lead many people to become vegetarian, made the authors of this new study curious. And since other research has found that genetics can influence our food choices in general, they wanted to see if the same was true for vegetarianism specifically.
To do this, the researchers turned to the UK Biobank, a long-running research project that’s collected genetic and other health data from hundreds of thousands of the country’s residents. Then they ran a genome-wide association study (GWAS)—a type of analysis that looks for genes or genetic variants statistically linked to diseases or traits in a large group of people.
The team compared the genetics of over 5,000 people who identified as strictly vegetarian (meaning they reported not eating any fish, meat, or poultry) to over 320,000 controls. Overall, they identified three genes with a clearly significant association to vegetarianism, and another 31 genes that had a potential association to the trait.
The research, published Wednesday in PLOS-One, is the first of its kind, according to study author Nabeel Yaseen, a professor emeritus of pathology at the Northwestern University Feinberg School of Medicine.
“Our study is the first fully peer-reviewed and indexed study to address the genetics of vegetarianism,” he told Gizmodo in an email.
GWAS studies help scientists pinpoint the many ways that genetics can affect our lives, but they have caveats. Like other types of observational research, for instance, they can only show a correlation between any two variables, not prove a direct causal relationship. And in this case, there’s still a lot we don’t know about the potential genetic underpinnings of vegetarianism.
“We have shown that vegetarians show significant genetic differences from non-vegetarians and identified several candidate genes. However, we do not know which of the genes we identified and what variants of those genes are critical for vegetarianism,” Yaseen said.
That said, the findings should provide scientists a few clues on where to look next. Some of the genes the team found are known to affect how we metabolize lipids (fats) in our food, for instance. Meaty foods also tend to have complex lipids that are different from what’s usually available in plant products. It’s possible, Yaseen theorizes, that our strong preference for meat is influenced by our unconscious need for these lipids, and that strict vegetarians tend to possess genetic variants that allow them to produce these lipids on their own. But at this point, that’s only speculation, he adds.
Other important questions that the team hopes they or other scientists can explore in the future include whether these vegetarian-related genes and variants can be found in ethnic groups other than white Caucasians (to avoid potential confounders, the team focused their analysis on this group alone). And ultimately, what we learn from this research might someday allow us to better personalize dietary recommendations or even produce better meat substitutes.