It’s not often that a nutrition study makes researchers stop and say, now that’s interesting. But a new analysis of more than 1.8 million people has done exactly that, showing that vegetarians face meaningfully lower risks for several major cancers compared with meat eaters.
Published in the British Journal of Cancer, the work found reduced risk across five cancer types. Vegetarians had a 21 percent lower risk of pancreatic cancer, 12 percent lower risk of prostate cancer, and 9 percent lower risk of breast cancer. Those three alone account for roughly one in five cancer deaths in the UK.
The drops didn’t stop there. Vegetarians also had a 28 percent lower risk of kidney cancer and a 31 percent lower risk of multiple myeloma. Dr Aurora Pérez-Cornago, the study’s principal investigator, called the findings “really good news for those who follow a vegetarian diet.”
Researchers pulled data from several long-running health studies worldwide, giving them a rare sample size large enough to study not just common cancers, but the rarer ones too. In total, the analysis covered about 1.64 million meat eaters, 57,016 poultry eaters, 42,910 pescatarians, 63,147 vegetarians, and 8,849 vegans, tracked for an average of 16 years. Key factors like smoking and body mass index were accounted for.
But the picture wasn’t uniformly protective. Vegetarians had nearly double the risk of squamous cell carcinoma of the oesophagus compared with meat eaters, something the researchers suggest may be tied to nutrient gaps, including B vitamins. Vegans, meanwhile, had a 40 percent higher risk of bowel cancer, which may reflect low average calcium intake and other dietary deficiencies. Their typical calcium intake in the study, 590 mg per day, fell below the UK’s 700 mg recommendation.
The team is cautious about drawing firm conclusions on what drives the differences. Prof Tim Key, a co-investigator, said it isn’t yet clear whether risks stem from meat itself or from something specifically protective in vegetarian diets. “My feeling is the difference is more likely to be due to the meat itself, but that’s an opinion that we haven’t looked at directly,” he said.
One notable wrinkle: vegetarians in this study didn’t show a lower risk of bowel cancer. Key said that finding aligns with previous research, given that red and processed meat intake in this cohort was relatively low. “It could be that if we had had more people with very high intakes of meat in the meat-eating group, the results could have been different,” he added.
The study also found benefits in other diet groups. Pescatarians had lower risks of breast, kidney and bowel cancers. Poultry eaters saw a lower risk of prostate cancer.
The researchers point out that diets have changed since many participants entered the studies in the 1990s and 2000s. Ultra-processed foods are more common, and vegan products today are often fortified with nutrients like calcium, which could shift future results. Prof Jules Griffin of the University of Aberdeen, who wasn’t involved in the study, praised the scale of the work but noted one gap: there was no comparison group eating the NHS Eatwell diet, which emphasises moderation in meat and fish and could represent a strong benchmark for reducing cancer risk.
For now, the study offers a clearer map of how diet and cancer risk intersect across millions of lives — and where researchers still need answers.
