Genetics may influence ability to maintain vegetarianism

Genetic variants that may help some people maintain a vegetarian diet better than others have been identified.

Scientists based at Northwestern University, Illinois, used a genome-wide association study (GWAS) to analyse genetic data from around 335,000 people stored in the UK Biobank database. GWAS allows researchers to test thousands of genetic variants to determine if any are statistically associated with a specific trait, such as vegetarianism. In this study, the researchers compared the genetic data of 5324 people who were strict vegetarians with 329,455 people who were non-vegetarians. They aimed to identify any genetic variations that may explain why some people have a better ability to maintain a vegetarian diet.

'Are all humans capable of subsisting long term on a strict vegetarian diet? This is a question that has not been seriously studied,' said lead author Professor Nabeel Yaseen from the Feinberg School of Medicine at Northwestern.

The researchers found a variant of chromosome 18 that was significantly associated with vegetarianism at the genome-wide level. Additionally, there were 201 variants that were suggestively associated with vegetarianism. Four genes were associated with the chromosome 18 variant: TMEM241, RIOK3, NPC1, and RMC1.

To further assess the GWAS data, the researchers used the Functional Mapping and Annotation platform, as well as the Multivariate Analysis of Genomic Annotation tool. Their analysis identified 34 genes with a possible link to vegetarianism. Furthermore, RIOK3, NPC1, and RMC1 were also found to be significantly associated with vegetarianism at the gene level.

Several of the genes associated with vegetarianism play important roles in lipid metabolism and brain function, which the research team have suggested may contribute to some people being able to subsist on a vegetarian diet.

Professor Yaseen explained 'one area in which plant products differ from meat is complex lipids. My speculation is there may be lipid component(s) present in meat that some people need. And maybe people whose genetics favour vegetarianism are able to synthesise 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.'

The recent study, published in the journal PLOS One, was the first time that peer-reviewed research had analysed an association between genetics and vegetarianism. To ensure that ethnicity did not affect the results of the study, the genetic data that the team analysed were from white Caucasians. Further research is needed to determine whether the genetic links to vegetarianism are consistent in people from different ethnic backgrounds.