“There might be something hard-wired in many of us that affects our dietary choices,” said Nabeel Yaseen, professor emeritus of pathology at Northwestern University's Feinberg School of Medicine.
“While many aspire to be vegetarians, not everyone can stick to it. This could be due to their genes.”
The team delved into the genetic make-up of 5,324 strict vegetarians, comparing their data with 329,455 controls.
Three genes strongly linked to vegetarianism were identified, with another 31 showing potential association.
Several of these genes, particularly NPC1 and RMC1, play roles in lipid metabolism or brain function.
“One highly speculative possibility is that meat may contain unique lipid nutrient(s) that those genetically predisposed to vegetarianism are able to synthesise endogenously while non-vegetarians need to obtain them from their diet,” Dr Yaseen told The National.
The global rise of vegetarianism has often been attributed to religious, moral and health reasons.
Yet vegetarians only make up a small portion of the global population: 3-4 per cent in the US and 2.3 per cent of adults in the UK.
Dr Yaseen believes that beyond taste, how our bodies metabolise food and drink significantly affects our dietary preferences.
Drawing parallels with how some acquire tastes for substances such as alcohol or coffee, he suggests a similar mechanism might be at play for meat.
But what does this mean for those who choose vegetarianism for religious or moral reasons?
“Our data show that genetics also play a part, but the relative contributions of genetic and environmental factors to the ability to adhere to a strict vegetarian diet are likely to vary from person to person,” he told The National.
“We hope that future research will identify critical genetic determinants that enable adherence to a vegetarian diet and therefore enable us to provide personalised dietary recommendations according to a person's genotype”.
This study, titled Genetics of Vegetarianism: A Genome-Wide Association Study, was conducted in partnership with scientists from Washington University in St Louis and Edinburgh, UK, and published in the journal PLOS One.