Vegetarians have substantially lower risk of five cancer types, study suggests

A pooled analysis of more than 1.8 million people followed for about 16 years found vegetarians had lower risks of pancreatic, prostate, breast, kidney cancers and multiple myeloma, while the study also reported higher risks of oesophageal squamous cell carcinoma in vegetarians and higher bowel cancer risk in vegans.

Researchers report that vegetarians had lower risks for several cancers in a large pooled analysis. The study combined data from multiple cohorts covering about 1.8 million people and was published in the British Journal of Cancer. Participants were followed for an average of 16 years and analyses adjusted for factors such as body mass index and smoking. The work was funded by the World Cancer Research Fund. Key findings: - Vegetarians had a 21% lower risk of pancreatic cancer, a 12% lower risk of prostate cancer and a 9% lower risk of breast cancer compared with meat eaters. - Vegetarians also showed a 28% lower risk of kidney cancer and a 31% lower risk of multiple myeloma. - Vegetarians were reported to have nearly double the risk of oesophageal squamous cell carcinoma compared with meat eaters. - Vegans had a reported 40% higher risk of bowel cancer versus meat eaters; the study noted lower average calcium intake among vegans in the pooled data. - The pooled sample included about 1.64 million meat eaters, 63,147 vegetarians and 8,849 vegans among other diet groups, with an average follow-up of 16 years. - The analysis found no overall lower risk of bowel cancer for vegetarians compared with meat eaters in this pooled data. Summary: The pooled analysis found associations between vegetarian diets and lower risks for several specific cancers, while also identifying higher risks for other cancer types in vegetarians and vegans. The researchers and external commentators said further research is needed to clarify whether the differences are due to meat consumption, particular features of vegetarian diets, or changes in diets over time. The pattern of associations appears to vary by cancer type, and researchers called for more detailed study of causes and mechanisms.