DEFINING FOOD COMPONENTS AS NEW NUTRIENTS

When obtained from a usual diet, a food component that sustains or enh ances physiological functions and/or prevents diseases is a nutrient. Isoflavones, tocotrienols, and carotenoids are candidate nutrients whi ch may be of health benefit to humans by inhibiting cancer development and reducing risk of atherosclerosis. The amounts of some of these ca ndidate nutrients in foods are known. A carotenoid data base has been developed. Isoflavone content of soy foods ranges from 0.1 mg/g (soymi lk) to 2.5 mg/g (soy protein isolate). Human bioavailability studies h ave also been performed with these candidate nutrients. For example, i n young adult females fed a single meal containing soy milk, isoflavon es were cleared from urine within 24 h after feeding, with about 15-20 % of the total dose accounted for in urine and feces. The two major so y isoflavones, genistein and daidzein, differ in bioavailability, with daidzein being more readily excreted in urine. Isoflavones, tocotrien ols, and carotenoids meet several criteria for classification as nutri ents. But after appropriate animal testing, food analyses, and availab ility studies have been performed, human health-protective efficacy mu st be proven in long-term feeding trials, in order for potential healt h-enhancing food components to be classified as nutrients.