A new gene study investigates how the biological evolution of humans in certain regions makes them more adapted to a plant-based a diet
NEW YORK’S CORNELL UNIVERSITY RESEARCHERS have found a fascinating genetic variation called the vegetarian allele, which appears to have evolved in populations that favored vegetarian diets over hundreds of generations. Their study, researching geographical diets in relation to vegetarians and meat eaters, was published in March, 2016, in the Journal of Molecular Biology and Evolution.
The scientists first analyzed the frequencies of the vegetarian allele in 234 primarily vegetarian Indians and 311 Americans living today. They found the vegetarian allele in 68 percent of the Indian group and in 18 percent of the Americans. They then analyzed information from the 1,000 Genomes Project—a database of global DNA—to estimate the frequency of the vegetarian allele in far-flung populations around the world.
The differences were striking: 70 percent of South Asians, 53 percent of Africans, 29 percent of East Asians and 17 percent of Europeans had the gene variation.
Research from the study shows how humans in some regions are genetically adapted to the consumption of plant-based foods more than others. Studies have suggested that humans evolved on a diet with a ratio of omega-6 to omega-3 essential fatty acids of 1:1, but that the Western diet has a ratio that is closer to 15:1 or even 16:1. The Mediterranean diet, in contrast, is closer to having an equal balance of the two and is recommended by many doctors.
This new study, funded by the National Institutes of Health and the US Department of Agriculture, shows that different people may need radically different ratios of these substances in their diet, depending on their genes. It supports the growing evidence against a one-size-fits-all approach to nutrition and for highly personalized advice.
The existence of the vegetarian allele, or another form of the same gene, implies that, for people with this variation, straying from that diet—by eating a lot of red meat, for example—may make them more susceptible to inflammation, because their bodies were optimized for a different nutritional mix.
Researcher Kaixiong Ye said the evolution of the vegetarian allele is less clear. It doesn’t exist in our ape relatives, the chimpanzee or orangutan, but there is some evidence it may have been there in early hominids, Neanderthal and Denisovan. It seems likely, the researchers wrote, that it has to do with migration patterns and the pressures that came with the availability, or lack thereof, of different kinds of foods in certain environments.
In a world where we have ready access to a wide variety of foods at local groceries, these adaptations may be able to act as guidance in helping to choose the kinds of foods our bodies are most suited for.
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