Orange and yellow vegetables like carrots, pumpkin, sweet potato, and winter squash are rich sources of beta-carotene. Spinach is also a rich source of beta-carotene, although the chlorophyll in spinach leaves hides the yellow-orange pigment. In addition fruits such as melon, papaya, orange, mango etc. are a very good source of carotenoids.
Beta-carotene can be converted in the body to vitamin A. The vitamin A activity of beta-carotene naturally contained in foods is one-twelfth that of retinol (preformed vitamin A). Thus, it would take 12 micrograms beta-carotene from foods to provide the equivalent of 1 microgram (0.001 mg) retinol (1).
Absorption of beta-carotene in food requires the presence of fat in a meal. Three to five grams fat in a meal appears sufficient to ensure absorption (48, 49).
For drinks and food fortified with isolated beta-carotene, a conversion rate of 4 micrograms beta-carotene to provide 1 microgram retinol is estimated.
Because of its vitamin A activity, beta-carotene can be used to provide all or part of the vitamin A in multivitamin supplements. Because they do not need to be released from the plant matrix, carotenoids in supplements are in general more efficiently absorbed than carotenoids in foods (49). The vitamin A activity of beta-carotene from supplements is generally even somewhat higher than from fortified foods. IOM (Institute of Medicine) defines the ratio as 2:1. However, the uptake and conversion of beta-carotene to vitamin A depends on many factors, including vitamin A status and genetic factors (see Safety).
Authored by Dr Peter Engel in 2010, reviewed and revised by Dr. Adrian Wyss on 28.09.17.
