London: A major international study has found that a vegetarian diet may lower the risk of developing several types of cancer by as much as 30 percent, although it could also increase the risk of certain others.
In the largest research of its kind, scientists from the University of Oxford reported that vegetarians have a 21 percent lower risk of pancreatic cancer and a 9 percent lower risk of breast cancer compared to meat eaters.
The study also found that vegetarians experience a 12 percent reduced risk of prostate cancer, a 28 percent lower risk of kidney cancer, and a 31 percent lower risk of multiple myeloma, a blood cancer.
Higher oesophageal cancer risk
However, the findings also showed that vegetarians have nearly double the risk of oesophageal squamous cell carcinoma, the most common type of oesophageal cancer, compared with meat eaters. Researchers suggested this may be linked to lower intake of key nutrients typically found in animal-based foods.
The study further examined vegetarian diets and found that vegans had a significantly higher risk of bowel cancer compared to meat eaters. One possible explanation is lower calcium intake among vegans, averaging 590 milligrams per day compared to the recommended 700 milligrams.
According to Cancer Research UK, adequate calcium intake can help reduce bowel cancer risk, with a large glass of milk daily associated with a 17 percent reduction. However, researchers cautioned that only 93 bowel cancer cases were recorded in the vegan group, meaning further investigation is required.
The research was led by Oxford Population Health, funded by the World Cancer Research Fund, and published in the British Journal of Cancer. It analysed global data primarily from the UK and the US and included 1.64 million meat eaters, 57,016 poultry-only eaters, 42,910 pescatarians (fish but no meat), 63,147 vegetarians, and 8,849 vegans.
The study investigated 17 different cancers, including those of the gastrointestinal tract, lungs, reproductive system, urinary tract, and blood. Dietary intake was assessed using food questionnaires covering participants’ typical eating habits over the previous 12 months. Researchers also adjusted for influencing factors such as body mass index to ensure more accurate comparisons.
It is already well established that processed meats, including ham, bacon, and salami, are linked to an increased risk of bowel cancer and possibly stomach cancer. Red meat such as beef, pork, and lamb also raises cancer risk, while no clear link has been found between white meat, such as chicken and turkey, and cancer.
Interestingly, vegetarians did not show a lower risk of bowel cancer compared to meat eaters, a finding researchers described as inconsistent with existing evidence linking processed and red meat to bowel cancer.
They suggested this may be because processed meat consumption in the meat-eating group studied was relatively moderate.
Aurora Perez Cornago, the study’s principal investigator, said that vegetarians typically consume more fruit, vegetables, and fibre and avoid processed meat, which may help explain the lower risks of some cancers.
However, Cornago added that the increased risk of oesophageal cancer in vegetarians and bowel cancer in vegans may relate to lower intakes of certain nutrients more abundant in animal foods. The investigator emphasised that additional research is needed to clarify what factors are driving the differences in cancer risk observed in the study.
Tim Key, emeritus professor of epidemiology at Oxford Population Health and co-investigator, noted that the differences in cancer rates between vegetarians and meat eaters were ‘not very big’ and may not fully explain the findings.
Key suggested the variations could be more closely related to meat consumption itself rather than simply vegetarians eating healthier foods, although this was not directly analysed.
Experts continue to advise building meals around wholegrains, pulses, fruits, and vegetables, while limiting processed foods and reducing red meat consumption as part of a balanced diet to lower overall cancer risk.
ALSO READ | ATX Open introduces private ‘Rage Room’ for players
