Long-term vegetarianism can lead to genetic mutations, raising the risk of heart disease and cancer, scientists have found. Populations that have had a primarily vegetarian diet for generations were found to be far more likely to carry DNA that makes them susceptible to inflammation.Scientists in the US believe the mutation occurred to make it easier for vegetarians to absorb essential fatty acids from plants.But it has the knock-on effect of boosting the production of arachidonic acid, which increases inflammatory disease and cancer. When coupled with a diet high in vegetable oils - such as sunflower oil - the mutated gene turns fatty acids into dangerous arachidonic acid.The finding may help explain previous research that found vegetarian populations are nearly 40% more likely to suffer colorectal cancer than meat eaters, a finding that has puzzled doctors because eating red meat is known to raise the risk.Researchers from Cornell University in the US compared hundreds of genomes from a primarily vegetarian population in Pune, India, to traditional meat-eating people in Kansas and found a significant genetic difference."Those whose ancestry derives from vegetarians are more likely to carry genetics that more rapidly metabolise plant fatty acids," said Tom Brenna, professor of human nutrition at Cornell."In such individuals, vegetable oils will be converted to the more pro-inflammatory arachidonic acid, increasing the risk for chronic inflammation implicated in the development of heart disease, and exacerbates cancer."The mutation appeared in the human genome long ago and has been passed down through the human family."The mutation hinders the production of beneficial omega-3 fatty acid, which protects against heart disease. Although it may not have mattered when the mutation first developed, since the industrial revolution there has been a major shift in diets away from omega-3 - found in fish and nuts - to less-healthy omega-6 fats - found in vegetable oils."Changes in the dietary omega-6 to omega-3 balance may contribute to the increase in chronic disease seen in some developing countries," said Brenna."The message for vegetarians is simple. Use vegetable oils that are low in omega-6 linoleic acid, such as olive oil."The mutation is found in the FADS2 gene, which controls the production of fatty acids in the body.Previous studies have shown that vegetarianism and veganism can lead to problems with fertility by lowering sperm counts.Separate research from Harvard University also found that a diet high in fruit and vegetables may affect fertility because men are consuming high quantities of pesticides.Many vegetarians also struggle to get enough protein, iron, vitamin D, vitamin B12 and calcium which are essential for health. One study found that vegetarians had approximately 5% lower bone-mineral density than non-vegetarians.However, other research suggests vegetarianism lowers the risk of diabetes, strokes and obesity. ..