Diet to Reduce Cancer Risk: Study of 2 Million People

A comprehensive analysis of nearly 1.8 million people has found that vegetarian diets are associated with a significantly lower risk of five specific types of cancer. The study, published on February 27, 2026, in the British Journal of Cancer, represents one of the largest investigations into the relationship between meat-free diets and cancer risk to date.

Researchers from the University of Oxford and the Cancer Risk in Vegetarians Consortium pooled data from nine prospective cohorts across three continents, including the United Kingdom, the United States, Taiwan, and India. The study tracked participants over a median period of 16 years to observe the incidence of various cancers among different dietary groups.

Key Findings on Cancer Risk Reduction

The analysis compared meat eaters with poultry eaters, pescatarians, vegetarians, and vegans. The data revealed that vegetarians had a lower risk of developing the following five types of cancer compared to those who ate meat:

• Pancreatic cancer
• Breast cancer
• Prostate cancer
• Kidney cancer
• Multiple myeloma

According to the study’s results, vegetarians showed a notably reduced risk for multiple myeloma, with a hazard ratio of 0.69 (95% CI 0.51–0.93), and kidney cancer, with a hazard ratio of 0.72 (95% CI 0.57–0.92). The risk for pancreatic cancer was also lower, recorded at 0.79 (95% CI 0.65–0.97).

Comparative Dietary Impacts

The research also highlighted differences in risk based on other plant-forward dietary patterns. Pescatarians—those who avoid meat but eat fish—were found to have lower risks of colorectal (0.85, 0.77–0.93), breast (0.93, 0.88–0.98), and kidney cancer (0.73, 0.58–0.93) compared to meat eaters.

Poultry eaters also demonstrated a slightly lower risk of prostate cancer, with a hazard ratio of 0.93 (0.88–0.98).

Unexpected Risks and Limitations

While the findings suggest protective benefits for several cancers, the study also identified some unexpected associations. The researchers found that vegetarians had a higher risk of squamous cell carcinoma of the oesophagus, with a hazard ratio of 1.93 (1.30–2.87).

the analysis indicated that vegans had a higher risk of colorectal cancer, with a hazard ratio of 1.40 (1.12–1.75), contrasting with the lower risk seen in pescatarians for the same type of cancer.

The researchers noted that the generalisability of these findings should be considered cautiously. They pointed out that vegetarian and vegan diets are typically higher in dietary fibre, carotenoids, and vitamin C, but lower in saturated fats, protein, and certain micronutrients like vitamin B12, which may contribute to these varying outcomes.

The study concludes that while vegetarian diets might influence the risk for several cancers, the results are complex and vary by the specific type of cancer and the specific dietary pattern adopted.