This report reviews current evidence regarding the relationship between vegetarian eating patterns and
cancer risk. Although
plant-based diets including vegetarian and
vegan diets are generally considered to be
cancer protective, very few studies have directly addressed this question. Most large prospective observational studies show that
vegetarian diets are at least modestly
cancer protective (10%-12% reduction in overall
cancer risk) although results for specific
cancers are less clear. No long-term randomized clinical trials have been conducted to address this relationship. However, a broad body of evidence links specific plant foods such as fruits and vegetables, plant constituents such as fiber,
antioxidants and other
phytochemicals, and achieving and maintaining a healthy weight to reduced risk of
cancer diagnosis and recurrence. Also, research links the consumption of meat, especially red and processed meats, to increased risk of several types of
cancer. Vegetarian and
vegan diets increase beneficial plant foods and plant constituents, eliminate the intake of red and processed meat, and aid in achieving and maintaining a healthy weight. The direct and indirect evidence taken together suggests that
vegetarian diets are a useful strategy for reducing risk of
cancer.