Health

Vegetarians have 12% lower cancer risk and vegans 24% lower cancer risk than meat-eaters, study finds.

An analysis of 79,468 North American Seventh-day Adventists in the Adventist Health Study-2 found that, after adjusting for lifestyle and demographic factors, vegetarians had a 12% lower risk of all cancers combined and vegans had a 24% lower risk compared to nonvegetarians.

The study tracked participants for almost eight years, matching cancer cases to state and provincial registries. Reduced risk was strongest for colorectal, stomach and lymphoproliferative cancers, with vegan diets showing notable protection against breast cancer in younger women and prostate cancer in younger men. Pesco-vegetarians had significantly lower colorectal cancer risk, while lacto-ovo vegetarians showed lower lymphoma rates. Medium-frequency cancers as a group, such as melanoma, thyroid, ovarian and pancreatic, were also less common in vegetarians.

Body mass index partially explained some differences, but dietary patterns themselves appeared influential, possibly due to higher intake of fruits, vegetables, legumes and nuts, and avoidance of processed or red meats, which are linked to carcinogenic compounds. No cancer type showed increased risk in vegetarians. Researchers highlight the role of plant-based nutrients and phytochemicals in reducing inflammation, supporting immune function and improving gut health. They caution that vegan diets should be balanced to prevent nutrient gaps, particularly vitamin B12, iron and omega-3 fatty acids, which may require fortified foods or supplements.

Strengths of the study include the large vegetarian sample, long-term stable diets, validated dietary measures and minimal confounding from smoking or alcohol. Limitations include reliance on baseline diet data, relatively small numbers for rare cancers and the observational design, which cannot confirm causation.

Source: Fraser, Gary E., et al. "Longitudinal Associations Between Vegetarian Dietary Habits and Site-Specific Cancers in the Adventist Health Study-2 North American cohort." The American Journal of Clinical Nutrition (2025).

• Flag
• Edit
• Delete
• Quote
• Reply