The “FADS2” diet: How vegetarian populations have different genomes

By Bryan Moyers

It turns out that what your ancestors ate can influence your ideal diet. At least, that’s what researchers at Cornell University and the University of Pune, in India, have announced after analyzing several hundred peoples’ genomes and blood samples in the United States and India.

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Image credit: Wikimedia commons

The relationship between risk of heart disease and certain kinds of diet is old news. But this finding points out that some populations are more influenced by the relationship than others. Particularly if your ancestors were mostly vegetarian.

Indian populations have often had many more vegetarians than European populations, and this has shaped their genomes. These genomes thus respond differently to modern diets, and have different risk of heart diseases.

The study examined the genetics of 311 people from the U.S. and Canada and 234 people from Pune, India. In India, there has been a long history of vegetarian diets, which are low in fatty acids.  Western diets have had much more meat, with greater amounts of fatty acids.  So the two populations have adapted to deal with different kinds of diets.  But modern diets in both the U.S. and India have much higher proportions of these fatty acids, meaning that we might expect people from different genetic backgrounds to respond differently.  The authors examined genes related to the production and processing of fatty acids looking for genetic differences.  They found that one genetic variant was much more heavily represented in the Indian population (67.5%) than in the U.S. and Canadian populations (8%).

The variant of interest was an addition of 22 letters in the FADS2 gene, a gene that regulates the production of long-chain polyunsaturated fatty acids. These acids are found all over the bodies of mammals, and are used both in the membranes of our cells and in important signaling pathways such as oxytocin (which promotes social bonding) and inflammation in the brain.  The FADS2 variant that was more common in the Indian population causes more efficient processing of fatty acids.

The body makes these fatty acids from precursor molecules found in the diet. These precursors are highly concentrated in fish and fatty red meats, but are harder to find in plants; so vegetarian populations have to be more efficient at producing these fatty acids.  While historically useful, the more efficient pathway common in India produces an overabundance of fatty acids when these precursors are much more common, as they are in modern diets.

Mutations in the FADS2 gene have long been associated with diseases such as eczema and hay fever, and we now know that it also affects metabolism. This adds to the insights that have been accruing since the completion of the human genome project, some fifteen years ago.

The finding also suggests that other populations might have similar genomic differences. For instance, Inuit populations that survive mostly on fish are likely to have had changes to the same genes and regions of the genome.

Realistically, what does this mean for your own personal diet? Probably not much! This is one little bit of knowledge among many that doctors and dieticians can use for people at risk of developing, or increasing the severity of, heart disease.

About the author

 

bryanOur second co-founding editor, Bryan Moyers, is a doctoral student in the Bioinformatics program at the University of Michigan. Bryan’s research focuses on methodological problems in molecular evolution, and correctly inferring information from data. In other words, his research sheds light on problems with the methods commonly used in the field of Evolutionary Biology so that improvements can be made. Bryan holds degrees in Biology and Psychology from Purdue University. His interests are in science and education issues, philosophy of science, and the intersection of science and business. Outside of science, Bryan enjoys reading, running, hiking, and brewing/consuming beer.

Read more from Bryan here.

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