Vegetarianism over generations can result in genetic mutations which increase the risk of heart disease and cancer.

Researchers found a long-term vegetarian diet means populations are more likely to carry DNA that makes them vulnerable to inflammation.

The mutation is believed to make it easier for vegetarians to absorb necessary fatty acids from plants, but also boosts their production of arachidonic acid, which increases inflammatory disease and cancer.

Over generations, a vegetarian diet can result in genetic mutations which increase the risk of heart disease and cancer, scientists claim (file photo)

This, coupled with a diet rich in vegetable oils, means the mutated gene turns fatty acids into arachidonic acid.

The problem is also worsened because the mutation obstructs the production of Omega 3, which protects against heart disease.

This is an increasing issue given the shift in people’s diets away from fish and nuts, which contain valuable Omega 3, to vegetable oils, which contain the unhealthier Omega 6.

The new findings provide an explanation for previous studies which found that vegetarians were up to 40 per cent more likely to develop bowel cancer than those who eat meat.

Until now, doctors had been confused by this research, since red meat is known to increase the risk of cancer.

The research by Cornell University, compared hundreds of genomes from a mostly vegetarian population in Pune, India to meat eaters in Kansas, and found a notable genetic difference.

Tom Brenna, Professor of Human Nutrition at Cornell University, said: ‘Those whose ancestry derives from vegetarians are more likely to carry genetics that more rapidly metabolise plant fatty acids.

The genetic mutation boosts vegetarians' production of arachidonic acid - a fatty acid which increases inflammation in the body - raising the risk of heart disease and cancer (file photo)

‘In such individuals, vegetable oils will be converted to the more pro-inflammatory arachidonic acid, increasing the risk for chronic inflammation that is 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.’

Vegetarians are often found to be deficient in protein, iron, vitamin D, vitamin B12 and calcium, with one study showing that vegetarians had a five per cent lower bone-mineral density than those who eat meat.

Other research, however, has said that vegetarians are less likely to suffer from diabetes, obesity and strokes.