Epidemiological evidence for the impact of whole grains on health.

Current dietary advice suggests consumers increase consumption of whole-grain products because of their potential role in prevention of chronic disease. Whole grains are important sources of nutrients that are in short supply in our diet, including dietary fiber, resistant starch, trace minerals, certain vitamins, and other compounds of interest in disease prevention, including phytoestrogens and antioxidants. Despite dietary recommendations to increase intake of whole grains, little epidemiological evidence is available to support the physiological importance of whole-grain intake. Most epidemiological studies focus on nutrients, rather than whole foods, so little attempt has been made to evaluate the contribution of whole grains in disease. Further, studies on vegetarians that show decreased risk of degenerative diseases are unable to separate the contribution of fruit and vegetable intake when compared with whole-grain intake and protection from disease. The few epidemiological studies that have evaluated a role for whole grains suggest that they have an important role in disease prevention and deserve more study.