CIMMYT Series on Carbohydrates, Wheat, Grains, and Health: Carbohydrates, Grains, and Whole Grains and Disease Prevention. Part III. Cancer Risk: Overview, Breast, and Colorectal1,2 To address many current claims that discourage the ingestion of carbohydrates (CHOs), wheat, and cereal grains, as well as to celebrate the versatility, nutritional and health benefits, and contribution of these foods to the world food supply, we felt compelled to defend their role in the diet and write a series of reviews. The seventh review in this series assesses the scientific literature with respect to the impact of whole, refined, and enriched grains and the CHOs they contain, including starch, dietary fiber, and resistant starch, on two of the most common cancers worldwide: breast and colon/rectal cancers. Included in this review is an overview on the relationship between cancer risk and diet. The totality of the data from most large prospective cohorts indicates that total CHO intake is not related to breast or colorectal cancers. Dietary fiber intake appears to be inversely related to colon cancer and to have either no or an inverse association with breast cancer. Most studies show only a slight increase in risk of breast and colon cancers associated with refined grain intake. When the available evidence is considered as a whole, there appears to be support for the following general dietary recommendations. For diets in which calorie intake matches energy needs, in which food groups are represented in recommended amounts, and in which there is a mix of whole and refined staple grains, there seems to be less risk for developing certain cancers. Adequate dietary fiber from this balance of foods, including those from brans and whole grains, positively impact the immune system, microbiome, gut transit, and colonic fermentation, which significantly contributes to general health and decreased cancer risk. |