Children who have high IQs are more likely to decide to be vegetarian as adults, according to a new study published Friday by the on-line British Medical Journal (www.bmj.com).
Recent evidence suggests that vegetarianism may be linked to lower cholesterol levels and a reduced risk of obesity and heart disease.
This might help to explain why children who score higher on intelligence tests tend to have a lower risk of coronary heart disease in later life.
The 20-year prospective study, carried out by Dr. Catharine Gale and colleagues at the University of Southampton and Southampton General Hospital in the UK, included 8,179 men and women aged 30 years whose IQ was tested at age 10.
Two decades later, 366 (4.5 percent) of participants said they were vegetarian. Of these, nine (2.5%) were vegan (strict vegetarians who consume no animal products) and 123 (33.6%) stated they were vegetarian but reported eating fish or chicken. There was no difference in IQ score between strict vegetarians and those who said they did not eat meat but did eat fish or chicken.
Vegetarians were more likely to be female, to be of higher occupational social class and to have higher academic or vocational qualifications than non-vegetarians, although these differences were not reflected in their annual income, which was similar to that of non-vegetarians.
Higher IQ at the age of 10 years was associated with an increased likelihood of being vegetarian at the age of 30. This relationship was partly accounted for by better education and higher occupational social class, but it remained statistically significant after adjusting for these factors, the researchers said.
The finding that children with greater intelligence are more likely to report being vegetarian as adults, together with the evidence on the potential benefits of a vegetarian diet on cardiac health, may help to explain why higher IQ in childhood or adolescence is linked with a reduced risk of coronary heart disease in adult life, the authors suggested.
Alternatively, the link may be merely an example of many other lifestyle preferences that might be expected to vary with intelligence, but which may or may not have implications for health, they conclude.