In a paper published online Wednesday in the American Journal of Clinical Nutrition, Oxford researcher Francesca Crowe and her team followed the health of nearly 45,000 men and women in England and Scotland over an average of 11 years. Thirty-four percent of the study's participants adhered to a vegetarian diet at the beginning of the study.
Over the course of the study, there were 1,235 cases of ischemic heart disease, including 169 deaths from the condition. Ischemic heart disease occurs when a person’s heart muscle isn’t getting enough blood, and it is the most common cause of death in much of the developed world.
When they ran the numbers, the Oxford team found that vegetarians had a 32 percent lower risk for ischemic heart disease than the meat-eaters.
“Most of the difference in risk is probably caused by effects on cholesterol and blood pressure, and it shows the important role of diet in the prevention of heart disease,” Crowe said in a statement on Wednesday.
The vegetarians in the study also had a lower body-mass index, on average, than the meat-eaters. When the researchers accounted for the BMI difference, the numbers still didn’t shift dramatically -- there was still a 28 percent advantage in heart disease risk for the vegetarians, so BMI was not the dominant factor in the differences between the two groups. Nor did sex, age, smoking habits, or other risk factors for heart disease nudge the numbers significantly.
Other research points to the health benefits of vegetarian diets. A 2009 review article by Loma Linda University researcher Gary Fraser in the American Journal of Clinical Nutrition underscored the heart benefits of cutting out meat, particularly because animal fats raise levels of LDL cholesterol (the “bad” kind of cholesterol).
There is some evidence that vegetarians also have lower risks for certain cancers, though some specific cancers need more study. But “there is general agreement that red meat consumption increases the risk of colon or colorectal cancer,” Fraser wrote.
However, some vegetarians may not be getting all the nutrients they need without meat. Non-meat eaters have to take care to get all the protein their bodies need from plant sources. They may also need to take supplements to combat certain nutritional deficiencies, particularly in vitamins B12 and D, as well as calcium, iron and zinc.
SOURCE: Crowe et al. “Risk of hospitalization or death from ischemic heart disease among British vegetarians and nonvegetarians: results from the EPIC-Oxford cohort study.” American Journal of Clinical Nutrition published online 30 January 2013.