A British study of more them 8 000 men and women aged 30 whose IQs had been measured when they were 10, showed that the higher the IQ, the greater the odds of being a vegetarian.
"People who are more intelligent as children, who will obviously keep that intelligence when they are 30, were more likely to say they are vegetarians at that age than those that were less intelligent," said Dr Catherine Gale, an epidemiologist at the University of Southampton in England.
She added the findings, which are published online by the British Medical Journal, were consistent with other studies showing people who are more intelligent tend to eat a healthier diet and exercise more.
"There is quite a lot of evidence linking vegetarianism to a lower risk of heart disease. People who are vegetarians tend to have lower blood pressure, lower cholesterol levels and they do have a lower risk of dying from coronary heart disease," Gale added.
For each 15-point rise in IQ scores in the study, the likelihood of being a vegetarian rose by 38 percent. Even after adjusting to factors such as social class and education, the link was still consistent.
More than 33 percent of the men and women in the study described themselves as vegetarians but said they ate white meat and fish. Just over four percent were strict vegetarians and 2.5 percent were vegans, who eat no animal products at all, including eggs and dairy.