We’ve all heard the well-known saying “you are what you eat”. It turns out that even scientists support this saying. A group of scientists from the Cornell University conducted a study where it was shown that cultures that have adhered to strictly vegetarian diets for many generations have developed a unique genetic mutation that could put them at increased risk for heart disease and colon cancer.
Our body has a great need of fatty acids as they play important roles in how we store energy and grow and repair cells. The European Food Information Council suggests that our body can produce fatty acids if needed, except for two: omega-6 fatty acids and omega-3 fatty acids, and these are only found in specific foods.
Converting plants into fatty acids is a complicated metabolic process for our bodies. While animals can metabolize the nutrients from the plants into fatty acids, our body absorbs them when we eat that specific animal. As for vegetarians, their body must complete the process on its own, metabolizing the fatty acids directly from their plant diet.
In order to break down omega-6 and omega-3 fatty acids so that our body can use them for brain development and controlling inflammation, our body uses the enzymes FADS1 and FADS2. During the study, the researchers identified a mutation, rs66698963, in the gene responsible for expressing FADS 1 and FADS 2.
An insertion mutation, characterized by extra base pairs, caused an increase in the production of the two enzymes and a better ability to produce fatty acids from plants — which is why it was dubbed the vegetarian allele.
The researchers observed the variation of this insertion among 234 primarily vegetarian Indians and 311 meat-eating Americans (mostly from Kansas). It was discovered that insertions existed in 68 percent of the Indians but only 18 percent of Americans. Mind you that the Indians had practiced vegetarianism for thousands of years.
By using data from the 1000 Genome Project, they found out that vegetarian allele existed in 70 percent of South Asians, 53 percent of Africans, 29 percent of East Asians, and just 17 percent of Europeans. Even though the insertion helps vegetarians to produce the fatty acids, it elevates their health risks. In the body, omega-3 fatty acids constantly compete with omega-6 fatty acids to be metabolized.
If your diet has more omega-6 fatty acids than omega-3s, then there’s a specific imbalance happening in your body that increases the risk of heart diseases and colon cancer. But, the co-author of the study, Dr. Alon Keinan, explained to the Medical Daily that there is an easy way for those whose ancestors were vegetarians to avoid these health risks.
“Those with an ancestral history of vegetarianism] would do perfectly well, as long as they avoid some foods that are vegetarian but high in omega-6, specifically plant-based oil,” Keinan wrote in an email. “More in general, vegetarians in industrialized countries tend to rely heavily on plant-based oil, which is rich in omega-6, and can lead to inflammation-related diseases.”
An opposite type of mutation was found in Inuit Natives in Greenland whose diet is mainly based on fish and other marine animals. Instead of insertion, these people had deletion, or the absence of a section of DNA. This condition can lead to health issues, such as colitis and other immune disorders.
“Our study is the first to connect an insertion allele with vegetarian diets, and the deletion allele with a marine diet,” said co-lead author Kaixiong Ye in a recent statement. According to him, the two genetic variations probably emerged early in our evolutionary history, when people around the world migrated to different environments. “Sometimes they ate a plant-based diet and sometimes they ate a marine-based diet, and in different time periods these different alleles were adaptive.”
Another diet-based mutation is the human ability to digest milk. Even though people are born with the ability to break down the enzymes in milk, there are some people who lose the ability once they reach adulthood. A genetic mutation that allows some people to keep drinking milk, however, is common among modern Europeans and those of European descent.
Berkeley University states that around 10 percent of Americans are lactose-intolerant compared to 99 percent of Chinese. This is because having the gene for lactose tolerance was only advantageous in cultures that had access to domesticated dairy animals, and relied on them for food and milk.