Vegetarians Experience Lower Cancer Risk in Comprehensive Research
A landmark study on diet and health has uncovered that vegetarians possess a significantly reduced risk of developing five specific types of cancer. The research, which analyzed data from over 1.8 million individuals tracked for many years, provides compelling evidence for the protective effects of a vegetarian diet against certain malignancies.
Key Findings on Cancer Risk Reduction
The study, published in the British Journal of Cancer, 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. Collectively, these cancers are responsible for approximately one-fifth of all cancer-related deaths in the United Kingdom.
Additionally, vegetarians demonstrated a 28% lower risk of kidney cancer and a 31% lower risk of multiple myeloma. Dr. Aurora Pérez-Cornago, the principal investigator during her tenure at the University of Oxford, emphasized the positive implications, stating, "This study is really good news for those who follow a vegetarian diet because they have a lower risk of five cancer types, some of which are very prevalent in the population."
Notable Exceptions and Potential Explanations
Despite the overall protective benefits, the research identified some exceptions. Vegetarians were found to have nearly double the risk of squamous cell carcinoma, the most common type of oesophageal cancer, compared to meat eaters. Scientists speculate this may be linked to deficiencies in key nutrients, such as B vitamins, among vegetarians.
Vegans, in particular, showed a 40% higher risk of bowel cancer relative to meat eaters. This increased risk could be attributed to lower average intakes of calcium and other essential nutrients, with vegans consuming an average of 590mg of calcium per day, below the UK recommendation of 700mg.
Research Methodology and Limitations
To address the challenge of low numbers of vegetarians and vegans in previous studies, this research compiled data from various global studies on diet and health. The analysis included approximately 1.64 million meat eaters, 57,016 poultry eaters, 42,910 pescatarians, 63,147 vegetarians, and 8,849 vegans, with participants followed for an average of 16 years. Factors like body mass index and smoking were adjusted for to ensure accuracy.
Prof. Tim Key, emeritus professor of epidemiology at the University of Oxford and co-investigator, noted the need for further investigation, saying, "My feeling is the difference is more likely to be due to the meat itself, but that's an opinion that we haven't looked at directly." The study, funded by the World Cancer Research Fund, examined 17 different cancers, including those of the gastrointestinal tract, lung, reproductive system, urinary tract, and blood cancers.
Additional Insights from Dietary Groups
Pescatarians were found to have lower risks of breast and kidney cancers, as well as a reduced risk of bowel cancer. Poultry eaters also exhibited a lower risk of prostate cancer. However, there was no evidence that vegetarians had a lower risk of bowel cancer compared to meat eaters, possibly due to relatively low red and processed meat intake in the study group.
Prof. Jules Griffin, director of the Rowett Institute at the University of Aberdeen, who was not involved in the research, praised the study but highlighted a gap, adding, "What is missing in this study is a comparison to a group eating the NHS Eatwell guidelines, where meat and fish consumption is in moderation, but at the same time provides important nutrients to the diet – this may be the optimum diet for reducing risk in the population for diet associated cancer."
Evolution of Diets and Future Directions
The study's long-term tracking, with participants recruited as early as the 1990s and 2000s, means diets have evolved over time. For instance, ultra-processed foods have become more common, and vegan products like oat milk are now often fortified with calcium and other nutrients. This underscores the need for ongoing research to understand how modern dietary trends impact cancer risk.
Overall, this comprehensive analysis offers valuable insights into the complex relationship between diet and cancer, highlighting both the benefits and potential drawbacks of vegetarian and vegan lifestyles.
