Intelligent children may be more likely to become vegetarian. Those recorded as having a high IQ aged 10 were more likely to be vegetarian aged 30, it said.
The research, published online in the British Medical Journal (BMJ), involved a study of 8,179 men and women. Aged 30, 366 (4.5%) of them said they were vegetarian. Of those, nine (2.5%) were vegan while 123 (33.6%) said they were vegetarian but ate fish or chicken.
On average, vegetarians had a higher childhood IQ score than non-vegetarians. The mean childhood IQ score of vegetarians compared with non-vegetarians was 106.1 and 100.6 for men and 104 and 99 for women.
It is already known that children with a high IQ have lower risk of coronary heart disease in later life – something the researchers said could be down to a vegetarian diet which is also regarded as good for the heart.
They said: “Vegetarians were more likely to be female, to be of higher social class (both in childhood and currently), and to have attained higher academic or vocational qualifications, although these socio-economic advantages were not reflected in their income.
“Higher IQ at age 10 years was associated with an increased likelihood of being vegetarian at age 30.
“IQ remained a statistically significant predictor of being vegetarian as an adult after adjustment for social class, academic or vocational qualifications, and sex.”
The authors also noted that, compared with non-vegetarians, vegetarians were less likely to be working in the private sector and more likely to be working for charities, local government, or in education.
Overall, 17% of the vegetarians worked in education compared with 9% of non-vegetarians. When asked as part of a follow-up survey what they thought of the statement “The Government should redistribute income,” 50% of vegetarians said they agreed compared with 41% of non-vegetarians. The proportion was even higher among male vegetarians (61% versus 42%).
The authors concluded: “Our finding that children with greater intelligence are more likely to report being vegetarian as adults, coupled with the evidence on the potential benefits to cardiovascular health of a vegetarian diet, may help to explain why higher IQ in childhood or adolescence is linked with a reduced risk of coronary heart disease in adult life.”
They said there was no difference in IQ score between strict vegetarians and those who said they were vegetarian but who ate fish or chicken.