Vegetarians have a 14% lower chance of developing cancer than carnivores, according to a large study linking meat consumption to an increased risk of the disease.
A team of researchers from the University of Oxford analyzed data from more than 470,000 Britons and found that pescatarians had a 10% lower risk. Compared with people who eat meat regularly, defined as more than five times a week, those who ate small amounts had a 2% lower risk of developing cancer, the study found.
“In this large British cohort, being a low meat eater, fisherman or vegetarian was associated with a lower risk of all cancer sites compared with regular carnivores,” the analysis found.
However, the authors, led by Cody Watling of Oxford Population Health’s cancer epidemiology unit, made it clear that their findings did not conclusively prove that regular meat consumption increases cancer risk. Smoking and body fat could also help explain the differences found, they said.
Their study of participants in the UK Biobank study also found that:
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Low meat eaters, who eat meat five or fewer times a week, had a 9% lower risk of developing bowel cancer than regular meat eaters.
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Vegetarian women were 18% less likely than those who regularly ate meat to develop postmenopausal breast cancer, although that may be due to their lower body mass index.
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Vegetarian men have a 31% lower risk of prostate cancer, while among pescetarian men it is 20% lower.
“The results…suggest that specific dietary behaviors such as eating little meat [and] vegetarian or pescetarian diets may have an impact on reducing the risk of certain types of cancer; in this case, intestine, breast and prostate,” said Dr. Giota Mitrou, director of research and innovation at World Cancer Research Fund International (WCRF), which co-funded the study with Cancer Research UK.
The results confirm longstanding WCRF advice that people should limit their consumption of red and processed meat and eat more whole grains, vegetables, fruits and legumes, he added.
The authors of the Oxford study said: “The lower risk of colorectal cancer [bowel] cancer in low-meat eaters is consistent with previous evidence suggesting an adverse impact of meat intake. Vegetarian women’s lower risk of postmenopausal breast cancer is likely to be explained “largely” by their lower BMI.
“It is not clear whether the other differences seen for all cancers and for prostate cancer reflect any causal relationship or are due to other factors.”
While the researchers found that “being a low meat eater, pescetarian, or vegetarian was associated with a lower risk of all types of cancer,” they added that this “may be the result of dietary factors and/or non-dietary differences in lifestyle, like like smoking.” Their results are published Thursday in the journal BMC Medicine.
Richard McIlwain, Executive Director of the Vegetarian Society, said: “This study adds to a growing body of research that reinforces the positive and protective effects of a vegetarian diet.
“With cancer now affecting one in two of us across the country, adopting a healthy vegetarian diet can clearly play a role in preventing this disease. In fact, evidence from previous surveys suggests that a balanced vegetarian diet may also reduce the risk of heart disease and diabetes, as well as cancers.”
Watling and his colleagues are conducting further research among vegetarians, pescatarians, and vegans to more closely examine the relationship between diet and cancer risk.
Between 5% and 7% of Britons are believed to be vegetarians and between 2 and 3% follow a vegan diet, according to YouGov polls.
Dr. Julie Sharp, head of health and patient information at Cancer Research UK, said that while reducing your intake of processed meat has been shown to reduce the risk of bowel cancer, “eating a bit of bacon or ham once in a while when it won’t do much damage.” and she added: “If you eat a lot of meat most of the time, cutting back is a good idea, but a vegetarian diet doesn’t always mean someone is eating healthy.”
