Eating vegetarian reduces cancer risk by up to 30%

A new study reveals that adopting a vegetarian diet can lower the risk of various cancers by up to 30%. The largest analysis of its kind shows a 21% reduced risk of pancreatic cancer and a 9% lower risk of breast cancer. However, some risks, like esophageal cancer, may increase for vegetarians due to nutrient deficiencies.

The largest analysis to date examining dietary patterns and cancer incidence has found that adhering to a vegetarian diet may substantially lower the risk of developing several types of cancer. According to the study, individuals who follow a vegetarian diet exhibit a 21% reduced risk of pancreatic cancer and a 9% lower risk of breast cancer compared to those who consume meat.

Key Findings on Cancer Incidence

• Men following a plant-based diet experienced a 12% lower likelihood of developing prostate cancer.
• The risk of kidney cancer was reduced by 28% among vegetarians.
• Multiple myeloma incidence was 31% lower in those adhering to a vegetarian diet.
• Conversely, vegetarians demonstrated nearly double the risk of oesophageal squamous cell carcinoma, the most common type of esophageal cancer, compared to meat eaters, possibly due to lower consumption of nutrients typically found in animal products.

Calcium intake among vegetarians averaged 590 milligrams daily, below the recommended 700 milligrams, which may contribute to a slightly higher risk of bowel cancer. Diets high in processed red meats, such as bacon, sausage, beef, pork, and lamb, have previously been linked to increased risks of bowel and stomach cancers. In contrast, consumption of white meats, including chicken and turkey, has not shown a significant correlation with cancer risk.

Study Design and Participants

The research was conducted by Oxford Population Health at the University of Oxford and funded by the World Cancer Research Fund. Data from multiple studies worldwide were analyzed, including participants from the United Kingdom and the United States. The study population included 64 million meat eaters, 57,016 poultry-only consumers, 42,910 fish-only consumers, and 63,147 vegetarians. Detailed dietary diaries covering one year were reviewed, and potential confounding factors such as body weight were accounted for in the analysis. Seventeen different types of cancer were examined across the cohort.

Findings Regarding Vegans and Bowel Cancer

Vegans were found to have a higher risk of bowel cancer than meat eaters, which may be linked to lower calcium intake. Previous research suggests adequate calcium consumption can reduce bowel cancer risk, with one study indicating that a daily glass of milk could lower risk by 17%. The Oxford study noted that only 93 bowel cancer cases were observed among vegans, highlighting the need for further research. For other cancers, no significant differences were observed between vegans and meat eaters, and the sample size was too small to draw conclusions for certain rarer cancers.

Vegetarian Diet Patterns and Cancer Risk

The analysis showed that vegetarians did not have a significantly reduced risk of bowel cancer compared to meat eaters. Nutrient differences between vegetarians and meat eaters, such as lower intake of certain animal-derived nutrients, may explain the higher risk of esophageal cancer in vegetarians and bowel cancer in vegans. Overall, the findings suggest a plant-based diet may offer protection against several cancers but requires careful attention to nutrient intake.

Expert Insights

Tim Key, emeritus professor of epidemiology at Oxford Population Health, noted that the number of vegetarians in the UK is approximately three million, and interest in vegetarian diets is growing internationally. Although vegetarians tend to consume more fiber, fruits, and vegetables, dietary differences alone do not fully explain the observed reduction in certain cancer risks. Helen Croker from the World Cancer Research Fund International advised focusing on whole grains, legumes, fruits, and vegetables while avoiding processed meats and limiting red meat to reduce overall cancer risk. Amy Hirst, health information manager at Cancer Research UK, emphasized that the results provide useful insights but are not definitive.

Conclusion

The study indicates that a vegetarian diet may reduce the risk of pancreatic, breast, prostate, kidney, and multiple myeloma cancers, while emphasizing the importance of ensuring adequate nutrient intake to offset potential risks, particularly for vegans. These findings underscore the need for ongoing research into the links between diet and cancer, aiming to identify the specific nutritional factors that influence cancer development.

Sources:

• The Guardian
• BBC News
• New York Times
• Vegetarian diet can slash the risk of five cancers by as much as 30%