Vegetarian Diet Linked to Lower Risk of 5 Cancers – New Study

A substantial body of research now suggests a link between vegetarian diets and a reduced risk of several cancers. A landmark study, analyzing data from over 1.8 million individuals, has revealed that people following a vegetarian diet experience a notably lower incidence of five specific cancer types. This finding, published in the British Journal of Cancer, adds to a growing understanding of the complex relationship between diet and cancer risk.

Dietary Patterns and Cancer Incidence

The research indicated a 21% lower risk of pancreatic cancer among vegetarians compared to those who regularly consume meat. Prostate cancer risk was reduced by 12%, and breast cancer risk by 9%. These three cancers collectively account for approximately 20% of all cancer-related deaths in the UK, highlighting the potential public health impact of these findings. Further analysis showed a 28% lower risk of kidney cancer and a 31% lower risk of multiple myeloma in vegetarians.

Dr. Aurora Pérez-Cornago, the principal investigator of the study, previously based at the University of Oxford, emphasized the positive implications for those adhering to a vegetarian lifestyle. “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,” she stated. The study’s strength lies in its scale, drawing on data from nine prospective studies across three continents.

Nuances and Potential Risks

Still, the study also revealed some unexpected associations. Vegetarians exhibited nearly double the risk of squamous cell carcinoma, the most common type of esophageal cancer, compared to meat-eaters. Researchers hypothesize this may be linked to potential deficiencies in key nutrients, particularly B vitamins, within vegetarian diets. Similarly, vegans showed a 40% higher risk of bowel cancer, potentially due to lower average calcium intake (590mg per day, below the UK recommendation of 700mg) and other nutrient shortfalls.

It’s important to note that correlation does not equal causation. While the study demonstrates an association between vegetarian diets and cancer risk, it doesn’t definitively prove that one causes the other. Other lifestyle factors, genetic predispositions, and environmental influences also play significant roles in cancer development. The researchers acknowledge the need for further investigation to determine whether the reduced cancer risk is directly attributable to the absence of meat consumption or to specific components of vegetarian diets.

Study Methodology and Scope

The comprehensive analysis involved data from approximately 1.64 million meat-eaters, 57,016 poultry eaters (excluding red meat), 42,910 pescatarians (fish but no meat), 63,147 vegetarians, and 8,849 vegans. Participants were followed for an average of 16 years, allowing researchers to track cancer outcomes over an extended period. The study accounted for confounding factors such as body mass index and smoking habits to isolate the potential effects of diet.

Funded by the World Cancer Research Fund, the investigation encompassed 17 different cancers, spanning the gastrointestinal tract, lungs, reproductive system, urinary tract, and blood cancers. This broad scope allowed for a more holistic assessment of the relationship between dietary patterns and cancer risk.

Bowel Cancer Findings and Meat Consumption

Interestingly, the study did not find a statistically significant lower risk of bowel cancer among vegetarians compared to meat-eaters. Researchers suggest this may be due to relatively low levels of red and processed meat consumption within the study population, compared to more recent cohorts. Professor Tim Key, emeritus professor of epidemiology at the University of Oxford and co-investigator, noted that the findings are “not incompatible” with existing evidence linking red and processed meat to increased bowel cancer risk. Nature reports on this aspect of the study.

Dietary Variations and Cancer Risk

Beyond vegetarianism, the study also explored the impact of other dietary patterns. Pescatarians demonstrated lower risks of breast and kidney cancers, as well as a reduced risk of bowel cancer. Poultry eaters exhibited a lower risk of prostate cancer. These findings suggest that different dietary components may exert varying effects on cancer risk, highlighting the complexity of the relationship.

Evolving Diets and Future Research

The researchers acknowledge that dietary habits have evolved since the 1990s and 2000s, when many participants were initially recruited. The increased consumption of ultra-processed foods and the availability of fortified vegan products, such as calcium-enriched oat milk, may influence the current relevance of the findings.

Professor Jules Griffin, director of the Rowett Institute, University of Aberdeen, who was not involved in the research, emphasized the need for comparison to a diet aligned with the NHS Eatwell guidelines, which advocates for moderate meat and fish consumption alongside a balanced intake of nutrients. “This may be the optimum diet for reducing risk in the population for diet associated cancer,” he added.

What Comes Next: Ongoing Investigation and Guidance Updates

The findings from this study will likely prompt further research into the specific mechanisms by which vegetarian diets may reduce cancer risk. Future studies could focus on identifying the key protective compounds within plant-based foods and investigating the optimal nutrient intake for vegetarians and vegans. Public health organizations, such as the NHS and the World Health Organization, will continue to monitor emerging evidence and update dietary guidelines accordingly. It is crucial for individuals to consult with qualified healthcare professionals for personalized dietary advice.

Ongoing surveillance of cancer incidence and dietary patterns will also be essential to track trends and identify potential risk factors. This information will inform public health interventions and contribute to a more comprehensive understanding of the complex interplay between diet, lifestyle, and cancer development. ndph.ox.ac.uk provides further details on the study’s implications.