Vegetarian Diet Cuts Cancer Risk 28%
A major Oxford study finds that vegetarian diets are associated with lower cancer risk — by as much as 28% for kidney cancer and 31% for multiple myeloma. However, the same benefit was not observed for vegans, and a separate report suggests vegan diets may actually increase colorectal cancer risk. The findings underscore the complexity of nutrition science and highlight significant differences between vegetarian and vegan dietary impacts.
The landmark Oxford study, led by researchers at Oxford Population Health, was one of the largest of its kind, pooling data from over 1.8 million people across three continents. The research, funded by the World Cancer Research Fund, aimed to provide more definitive answers on how different dietary patterns influence the risk of specific cancers by including a substantial number of vegetarians and vegans. Beyond the cancers mentioned in the summary, the study found that vegetarians also had a 21% lower risk of pancreatic cancer, a 12% lower risk of prostate cancer, and a 9% lower risk of breast cancer compared to meat-eaters. The researchers attribute these lower risks partly to vegetarians typically consuming more fruits, vegetables, and fiber, and no processed meat. However, the same study revealed a concerning finding for vegetarians: nearly double the risk of squamous cell carcinoma of the esophagus compared with those who eat meat. Researchers have suggested this could be linked to lower intakes of certain nutrients that are more abundant in animal products, though they emphasize the need for more research to understand the exact cause. The increased risk of colorectal cancer in vegans, cited as approximately 40% higher than in meat-eaters, has sparked considerable discussion. Investigators suggest this may be linked to lower average calcium intake among vegans, as calcium is believed to help protect against this type of cancer. It is important to note that the researchers themselves have urged caution in interpreting the vegan and colorectal cancer link. The finding was based on a small number of cancer cases within the vegan group, and in one analysis, the difference was no longer statistically significant after a four-year follow-up period. The study also highlighted that pescatarians, who eat fish but not other meat, had a lower risk of colorectal, breast, and kidney cancers. This adds another layer of complexity, suggesting that it may not be the complete absence of meat, but rather the specific components of different diets that influence cancer risk. Experts not involved in the study point out that dietary habits have evolved over time. The data for this research was collected from cohorts recruited as far back as the 1980s, when vegan and vegetarian diets may have been nutritionally different than they are today, with the modern prevalence of fortified foods and highly processed meat alternatives. Principal investigator Dr. Aurora Pérez-Cornago and co-investigator Professor Tim Key from the University of Oxford both stress that more research is needed to understand the mechanisms behind these varied outcomes. They point to the need for more data on vegan diets specifically and from more diverse populations around the world to clarify the risks and benefits.
