“Functional foods,” “nutraceuticals,” “designer foods” and “medicinal foods” are terms that describe foods, and key ingredients isolated from foods, that have non-nutritive or tertiary functional properties. Researchers, healthcare practitioners, laypersons, and the popular media use these words interchangeably. The purpose of this article is to present valid scientific information available on the physiologic actions of known constituents and combinations of constituents, as they naturally occur in “functional foods,” highlighting their medicinal and nutritive mechanisms of action in the body.

The scientific community continues to recognize and validate the considerable relationship between vegetable intake and cancer. Over 200 epidemiological studies show, with great consistency, that a low consumption of vegetables is directly associated with an increased risk of cancer (Table 1). Epidemiological studies also support the belief that dietary modification, through an increase in vegetable intake, could reduce the risk of cancer by 50% internationally. Specifically, researchers regard cruciferous vegetables, and particularly those that are members of the Brassica plant family, as critical elements in the risk reduction associated with vegetable intake and cancer. [4-8] Further, in people under 55 years of age, cruciferous vegetable intake is inversely correlated with colon cancer incidence and comparatively among smokers the chemoprotective benefits of Brassica consumption are even greater. [9,10] Van Poppel et al.  examined 6 cohort studies and 74 case control studies that supported an in verse correlation between Brassica consumption and cancer risk. The association was found to be most consistent for lung, stomach, colon, and rectal cancers, and least consistent for prostatic, endometrial, and ovarian cancers. In studies examining total vegetable consumption an inverse association with cancer risk is also found, with the Brassicas showing the strongest effects as a subgroup. Brassicas also are low in fat, low in calories, and are potent sources of vitamins, minerals, fiber, and phytochemicals, all of which have been linked to cancer prevention.

A discussion of the biochemical and physiologic implications of increasing one’s intake of cruciferous vegetables will follow. The term “chemoprevention,” for the purpose of this research article, refers to the strategic approach of decreasing one’s susceptibility to carcinogenic factors through the administration of dietary chemicals, as introduced to the body within the matrix from which they originated (i.e., ingesting the whole vegetable vs. an isolated fraction). The rationale behind emphasizing the use of whole vegetables as opposed to an isolated fraction (considered a chemoprotective agent) is that the degree to which the protective effect of vegetables can be attributed to the nutritional or tertiary components, and to what extent indirect effects such as an equivalent reduction in fat consumption and associated increase in vitamin, fiber and carotenoid intake may be responsible for the protective effect, is not well defined. Nonetheless, the dietary approach of increasing one’s intake of cruciferous vegetables to defend oneself from cancer-causing agents has become widely recognized in the medical research community as a realistic and rational practice in the war against cancer.