Vegetarian diets might not be so healthy after all. A study conducted at Cornell University found that eating a vegetarian diet long-term changes DNA and makes people more susceptible to inflammation, which increases their risk for heart disease and colon cancer.

The researchers found that about 70 percent of people in India, a country where many people eat plant-based diets, had a higher frequency of a particular gene mutation compared to only 20 percent of meat-eating Americans.

The mutation is called rs66698963, and it is found in the FADS2 gene. The mutation, which occurred following generations of vegetarian diets, makes it easier for vegetarians to absorb omega-6 fatty acids from plants, but it also increases amounts of arachidonic acid.

Arachidonic acid is a type of omega-6 fatty acid. Although small amounts are essential for brain function and growth, when the ratio omega-6 to omega-3 becomes unbalanced, too much arachidonic is produced and leads to inflammation.

In vegetarian diets, the mutated gene converts fatty acids found in plant-based foods into arachidonic acid. In addition, the gene hampers the body from utilizing inflammation-fighting omega-3 fatty acids found in fish and some nuts, such as walnuts.

The study helps explain why vegetarians have a higher risk of colon cancer — up to 40 percent — than meat eaters.

The researchers concluded that the change in the balance of omega-6 to omega-3 fatty acids may be a factor in the increase in chronic disease seen in some developing countries.

The study was published in the journal Molecular Biology and Evolution.