A major study led by the University of Oxford highlights the link between the vegetarian diet and cancer risk, showing that vegetarians face up to a 31% lower risk of five cancers, including kidney and pancreatic cancers, though some risks appear higher for oesophageal and bowel cancers.
Vegetarians have a significantly lower risk of five types of cancer compared with meat eaters, according to a large international analysis published in the British Journal of Cancer.
Researchers at the University of Oxford report that vegetarians show a 31% lower risk of multiple myeloma, a blood cancer, and a 28% lower risk of kidney cancer. They also face a 21% lower risk of pancreatic cancer, a 12% lower risk of prostate cancer, and a 9% lower risk of breast cancer.
However, the study finds vegetarians have nearly double the risk of oesophageal squamous cell carcinoma, the most common form of oesophageal cancer. Vegans also show a higher risk of bowel cancer compared with meat eaters.
Study Analyzes 1.8 Million Diets Across 17 Cancers
The research, led by Oxford Population Health and funded by the World Cancer Research Fund, analyzes data from multiple studies worldwide. Most participants come from the United Kingdom and the United States.
The study includes 1.64 million meat eaters, 57,016 poultry eaters, 42,910 pescatarians, 63,147 vegetarians, and 8,849 vegans. Researchers examine 17 cancers, including those affecting the gastrointestinal tract, lung, reproductive organs, urinary tract, and blood.
Dietary habits are assessed through food questionnaires covering the previous 12 months or a typical diet. Researchers adjust for other factors that may influence cancer risk, including body mass index.
Aurora Perez Cornago, the study’s principal investigator, says dietary patterns likely explain part of the difference.
“Vegetarians typically consume more fruit, vegetables and fibre than meat eaters and no processed meat, which may contribute to lower risks of some cancers,” she says.
Researchers Probe Higher Risks In Vegetarians, Vegans
Despite the overall reduced risk for several cancers, researchers identify areas of concern.
A major study examining the vegetarian diet and cancer risk found that vegetarians show nearly double the risk of oesophageal squamous cell carcinoma compared with meat eaters, and Perez Cornago suggests this higher risk may relate to lower intakes of certain nutrients more abundant in animal foods.
The study on the vegetarian diet and cancer risk reports that vegans have a significantly higher risk of bowel cancer, with researchers noting that their average calcium intake of 590 milligrams per day falls below the recommended 700 milligrams. Previous findings from Cancer Research UK show that calcium lowers bowel cancer risk, with a large glass of milk per day linked to a 17% reduction.
However, the Oxford team cautions that only 93 bowel cancer cases occurred in the vegan group, limiting firm conclusions. “Additional research is needed to understand what is driving the differences in cancer risk found in our study,” Perez Cornago says.
For most other cancers, researchers find no significant difference in risk between vegans and meat eaters. In some rare cancers, the number of vegan cases is too small to analyze reliably.
Experts Debate Role Of Meat Versus Overall Diet
The findings add to existing evidence that processed meats such as ham, bacon, and salami increase the risk of bowel cancer and possibly stomach cancer. Red meat, including beef, pork, and lamb, also raises risk, while no clear link exists for white meat such as chicken and turkey.
The study found that the vegetarian diet and cancer risk does not show a lower risk of bowel cancer compared with meat eaters, and researchers suggest this may reflect relatively low processed meat consumption among meat eaters in the data.
Tim Key, emeritus professor of epidemiology at Oxford Population Health and co-investigator, says the differences in cancer rates are modest.
“My feeling is the differences are more likely to be related to meat itself than to simply vegetarians eating healthier foods,” Key says. He adds that this view remains an opinion not directly tested in the analysis.
Experts continue to advise building meals around whole grains, pulses, fruits, and vegetables, while limiting red and processed meat to reduce cancer risk.
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