People who ate fish but no meat had a lower risk of breast, kidney and bowel cancer than meat eaters, according to the largest analysis to date of diet patterns and cancer. The pooled study, published on February 27, 2026 in the British Journal of Cancer, followed more than 1.8 million adults across nine studies in the United Kingdom, United States, Taiwan and India.
The research was led by Oxford Population Health's Cancer Epidemiology Unit through the Cancer Risk in Vegetarians Consortium. Participants were tracked for a median of 16 years and grouped into meat eaters, poultry eaters, pescatarians (fish but no meat), vegetarians (dairy and/or eggs but no meat) and vegans.
Among the 42,910 pescatarians, breast cancer risk was 7 percent lower, bowel cancer risk was 15 percent lower and kidney cancer risk was 27 percent lower than in meat eaters. Vegetarians had lower risks across five cancers: pancreas, breast, prostate, kidney and multiple myeloma, a blood cancer that forms in plasma cells.
What the diet actually looks like
A pescatarian diet swaps red and processed meat and poultry for fish and seafood, while keeping plant foods, eggs and dairy on the plate. It sits between a fully plant-based diet and a conventional Western one, and it keeps two food groups that vegetarians and vegans skip: fatty fish rich in long-chain omega-3s, and the wider range of protein sources some people find easier to sustain.
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The World Cancer Research Fund recommends limiting red meat to three portions a week and eating "very little, if any, processed meat." Its scientists point to haem iron in red meat and to nitrites and nitrates added to processed meat as compounds that can damage the lining of the bowel and raise bowel cancer risk.
Why the pattern may matter
Diets built around plants and fish tend to be lower in saturated fat and higher in fiber, and they push out the processed meat linked most strongly to bowel cancer. A previous analysis has tied higher fiber intake to lower risk across a range of cancers, and the new pooled study points in a similar direction for the diets that deliver more of it.
"Vegetarians typically consume more fruit, vegetables and fibre than meat eaters and no processed meat, which may contribute to lower risks of some cancers," said Aurora Perez Cornago, the study's principal investigator and formerly Associate Professor at Oxford Population Health.
The picture was not uniformly positive. Vegetarians had a nearly doubled risk of squamous cell carcinoma of the esophagus, and vegans had a higher risk of bowel cancer. Perez Cornago said those signals "may relate to lower intakes of certain nutrients more abundant in animal foods."
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What the researchers stress
The findings come from observational studies, which show associations rather than cause and effect. Diet groups also differ in other ways, from smoking rates to body weight, and the analyses adjusted for known factors but cannot rule out all of them.
Yashvee Dunneram, the first author and a former postdoctoral epidemiologist at Oxford Population Health, said the vegetarian and vegan samples were still relatively small. "Among the 72,000 vegetarians and vegans included in our study, the numbers of cases for some cancers were small, which limits the certainty of some findings," she said.
Tim Key, Emeritus Professor of Epidemiology at Oxford Population Health, framed the takeaway in line with existing guidance. "Dietary patterns that prioritise fruit, vegetables, and fibre-containing foods, and avoid processed meat, are recommended to reduce cancer risk," he said.
For anyone thinking about a shift, the World Cancer Research Fund's cancer prevention recommendations are the practical starting point: keep red meat within three portions a week, eat very little processed meat, and build meals around whole grains, vegetables, fruit and beans.
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This article is made and published by Jesper Bengtson, who may have used AI in the preparation.