Fruit, Vegetables, and Folate: Cultivating the Evidence for Cancer Prevention

Abstract

Since the 1980s, the concept that a diet high in fruits and vegetables could reduce the risk of cancer has been promoted widely.1 A role for diet in preventing colon cancer held particular appeal in view of the direct contact of the colonic mucosa with nutrients and toxins from foods.2 Several mechanisms were suggested to account for these putative anti-neoplastic properties. Fiber derived from fruits, vegetables and grains was proposed to dilute or adsorb fecal carcinogens, modulate colonic transit time, alter bile acid metabolism, reduce colonic pH, or increase the production of short-chain fatty acids.3 Fruits and vegetables are also rich sources of micronutrients, including folate, which have been actively investigated as chemopreventive agents. More recently, emerging evidence has underscored the importance of the interplay between diet and the microbial ecology of the colon.4