Dietary provitamin A carotenoids in the prevention of vitamin A deficiency

Vitamin A is a fat-soluble vitamin obtained in the diet as preformed vitamin A from animal products and fortified foods and provitamin A carotenoids from plant sources. Preformed vitamin A is efficiently absorbed and stored in the body, and excess intake may lead to reduced bone mineral density and hip fracture. Provitamin A carotenoids rarely lead to excess vitamin A due to regulation of enzymatic conversion to vitamin A. Sustainable strategies to reduce the incidence of vitamin A deficiency in the developing world should include diversification of the food supply and increased access to provitamin A-rich foods. Additionally, dietary supplements formulated with provitamin A carotenoids in place of preformed vitamin A may be a safer delivery method for this important vitamin.;Many factors affect the bioavailability of provitamin A carotenoids and conversion efficiency to vitamin A from plants is generally accepted to be low. In a Mongolian gerbil model for vitamin A bioefficacy, we found that a provitamin A-rich dietary supplement made from whole foods and its component green vegetables were able to prevent vitamin A deficiency and demonstrated greater vitamin A equivalencies than those established by the Institutes of Medicine. A variety of orange fruits including mango, orange, tangerine, and papaya, were also able to prevent deficiency and had similar conversion efficiencies; however, the provitamin A carotenoids from banana, an important staple fruit in some parts of the world, did not prevent deficiency in this model and had a low efficiency of conversion.;Canots are known as a tasty and versatile orange vegetable, however, original carrots were purple and yellow. A modern purple canot with an orange core contains both yellow-orange provitamin A carotenoids, alpha- and beta-carotene, and anthocyanins, the pigments responsible for the purple color. Simultaneous consumption of these compounds could affect the bioavailability of carotenoids. In a human study, the plasma response of beta-carotene from purple carrots in a breakfast smoothie was not different from orange canots as measured by area-under-the-concentration curve. This was the first study in humans to confirm that purple cants are a functional food able to deliver these important phytochemicals.