Are You Vegetarian? Could Be Something in Your Genes

A recent study published in Molecular Biology and Evolution describes a phenomenon where populations that have typically consumed vegetarian diets over hundreds of generations have evolved a “vegetarian gene”.

This so-called “vegetarian gene” is truly a polymorphism represented by a 22 bp insertion within the FADS2 gene, which encodes an enzyme responsible for the desaturation of fatty acids such as omega-3 and omega-6. Researchers at Cornell University analyzed this genetic variation by comparing primarily vegetarian individuals from India and a random set of individuals from the U.S. and found that there was a much higher frequency of the homozygous polymorphism in the Indian population (68%) than in the U.S. one (18%). They then went on to confirm their observation using data from the 1000 Genomes Project, finding the polymorphism in 70% of South Asians, who traditionally have plant-based diets, versus 17% of Europeans, who are more likely to eat meat. Interestingly, the researchers found the opposite polymorphism, that is, a 22 bp deletion, in the same region of the FADS2 gene in the Intuit in Greenland, who have a mainly marine/seafood diet.

FADS2 and other members of the fatty acid desaturase (FADS) family are required to convert fatty acids into compounds needed for early brain development and controlling inflammation. The FADS2 enzyme is involved in endogenously synthesizing long chain polyunsaturated fatty acids (LCPUFA), which are bioactive compounds in phospholipid membranes. LCPUFA can also be obtained from animal foods, but vegans are dependent on FADS2 to generate these compounds. The insertion allele was shown to enhance LCPUFA synthesis and may confer an adaptive advantage in South Asians due to their dietary choices.

Source: Cornell University