Cancer: Epidemiology and associations between diet and cancer

Dietary factors account for a large proportion of human cancers, particularly overnutrition that results in weight gain and obesity. The evidence linking diet and cancer has been developing since the early 1900s, beginning with early laboratory studies and ecologic studies of cancer rates in different parts of the world. Modern epidemiologic methods, including case–control studies, cohort studies, Mendelian randomization studies, randomized controlled trials, and meta-analyses (particularly of individual participant data) have helped define in detail the associations between specific dietary factors and cancer. Factors with strong links to an increased risk of various cancers include: overnutrition/obesity, alcohol, red and processed meat, and salt. Factors with strong links to a decreased risk include: fruits, vegetables, whole grains, fiber, dairy, calcium, and coffee.