Oxford University researchers, who made the discovery, reckon the risk is reduced because vegetarians are probably eating less saturated fats, which they say block artery walls.
They compared the heart health of 15,100 vegetarians to 29,440 meat and fish eaters; while vegetarians were among the 169 people in the study who died from a heart attack during the 11 years the study ran, more of the deaths were among carnivores.
Overall, the vegetarians tended to have lower blood pressure and lower levels of the 'bad' LDL cholesterol.
However, the Oxford researchers didn't calculate how much meat or fish the carnivores were consuming nor how healthy the vegetarians' diet actually was.
(Source: American Journal of Clinical Nutrition,. 2013; doi: 10.3945/ajcn.112.048074).