A large-scale study involving over 1.8 million participants reveals that vegetarians experience a significantly reduced risk of several major cancers, while also highlighting potential nutritional deficiencies associated with certain plant-based diets. The research, published in the British Journal of Cancer, analyzed decades of dietary data to pinpoint specific links between meat consumption and cancer incidence.
Key Findings: Reduced Risk for Multiple Cancers
The study found that vegetarians 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. These cancers collectively contribute to approximately 20% of cancer-related deaths in the UK, making these findings particularly relevant. Further analysis showed a 28% lower risk of kidney cancer and a 31% lower risk of multiple myeloma among vegetarians.
Unexpected Risks: Oesophageal and Bowel Cancer
However, the study also revealed some counterintuitive results. Vegetarians showed nearly double the risk of squamous cell carcinoma, a common form of oesophageal cancer, potentially linked to deficiencies in essential nutrients like B vitamins. Similarly, vegans exhibited a 40% higher risk of bowel cancer compared to meat-eaters, possibly due to insufficient calcium intake (averaging 590mg daily against a recommended 700mg).
“These findings underscore the importance of balanced nutrition, even within vegetarian and vegan diets,” notes Dr. Aurora Pérez-Cornago, lead investigator of the study. “Simply eliminating meat does not guarantee optimal health.”
The Role of Meat: Correlation vs. Causation
Researchers emphasize that further investigation is needed to determine whether the reduced cancer risk is directly attributable to avoiding meat or to specific components of vegetarian diets. Prof Tim Key suggests the issue may lie in meat itself, but acknowledges this remains unproven. The study’s large sample size—over 1.64 million meat-eaters, 63,000 vegetarians, and nearly 9,000 vegans—allowed for more reliable conclusions than previous smaller studies.
Nuances in Dietary Patterns: Pescatarian and Poultry Benefits
The research also considered other dietary patterns. Pescatarians demonstrated lower risks of breast and kidney cancers, as well as bowel cancer, while poultry eaters showed a reduced risk of prostate cancer. This suggests that moderate inclusion of certain animal products may offer protective benefits without the same risks associated with red and processed meats.
Limitations and Future Research
The study acknowledges that dietary habits have evolved since data collection began in the 1990s and 2000s, with increased consumption of ultra-processed foods and fortified vegan products. Prof Jules Griffin, an independent researcher, points out the absence of a comparison group following balanced national dietary guidelines (like the UK’s Eatwell plate) as a limitation.
Ultimately, the study reinforces the complex relationship between diet and cancer risk, highlighting both the potential benefits of vegetarianism and the need for careful nutritional planning to avoid unintended health consequences.
