People from a long line of vegetarians who stray from the strict diet can put themselves at greater risk of heart disease and cancer, warns new research.
The study provides the first evolutionary work that traces a higher frequency of a particular mutation in a primarily vegetarian population in Pune, India.
The researchers found evidence that the vegetarian diet over many generations may have driven the higher frequency of a mutation in the Indian population.
The mutation affects two genes key to making long chain polyunsaturated fats, including arachidonic acid - a key target of the pharmaceutical industry because it is a central culprit for those at risk for heart disease, colon cancer and many other inflammation-related conditions.
Insertion of a string of DNA may occur in populations eating mainly vegetarian diets and possibly populations that don't have diets rich in polyunsaturated fats, such as fatty fish.
Interestingly, the deletion of the same sequence may have occurred in populations which are based on fish-based diet, such as the Greenlandic Inuit.
The authors of the study will follow it up with additional worldwide populations to better understand the mutations and these genes as a genetic marker for disease risk.
Dr. Tom Brenna, and Dr. Kumar Kothapalli, two of the study leaders, said: "With little animal food in the diet, the long chain polyunsaturated fatty acids must be made metabolically from plant PUFA precursors.
"The physiological demand for arachidonic acid, as well as omega-3 EPA and DHA, in vegetarians is likely to have favored genetics that support efficient synthesis of these key metabolites.
"Changes in the dietary omega-6 to omega-3 balance may contribute to the increase in chronic disease seen in some developing countries."
The study was published in the journal Molecular Biology and Evolution.