The challenge to reach nutritional adequacy for vitamin A: β-carotene bioavailability and conversion--evidence in humans.
β-Carotene is an important dietary source of vitamin A for humans. However, the bioavailability and vitamin A equivalency of β-carotene are highly variable and can be affected by food- and diet-related factors, including the food matrix, food-processing techniques, size of the dose of β-carotene, and the amounts of dietary fat, fiber, vitamin A, and other carotenoids in the diet as well as by characteristics of the target population, such as vitamin A status, nutrient deficiencies, gut integrity, and genetic polymorphisms associated with β-carotene metabolism. The absorption of β-carotene from plant sources ranges from 5% to 65% in humans. Vitamin A equivalency ratios for β-carotene to vitamin A from plant sources range from 3.8:1 to 28:1, by weight. Vitamin A equivalency ratios for β-carotene from biofortified Golden Rice or biofortified maize are 3.8:1 and 6.5:1, respectively, and are lower than ratios for vegetables that have more complex food matrices (10:1 to 28:1). The vitamin A equivalency of β-carotene is likely to be context-specific and dependent on specific food- and diet-related factors and the health, nutritional, and genetic characteristics of human populations. Although the vitamin A equivalency of β-carotene is highly variable, the provision of vegetable and fruit sources of β-carotene has significantly increased vitamin A status in women and children in community settings in developing countries; these results support the inclusion of dietary interventions with plant sources of β-carotene as a strategy for increasing vitamin A status in populations at risk of deficiency.
Program in International and Community Nutrition, Nutrition Department, University of California, Davis, Davis, CA 95616, USA. mjhaskell@ucdavis.edu
Marjorie J
MJ
Haskell
D001682:Biological Availability; D005638:Fruit; D006801:Humans; D007408:Intestinal Absorption; D009752:Nutritional Status; D014675:Vegetables; D014801:Vitamin A / Q000493:pharmacokinetics*; D014802:Vitamin A Deficiency / Q000378:metabolism / Q000517:prevention & control; D019207:beta Carotene / Q000493:pharmacokinetics*
D019207:beta Carotene; D014801:Vitamin A