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Vitamin Basics: Vitamin A

Vitamin A is the generic name for retinoids, a class of naturally occurring compounds that are found in both plant and animal sources. Retinoids are necessary for an effective immune system, and vitamin A deficiency (rare in most Americans) can increase your risk for infections. Although vitamin A is an essential nutrient, an excessive, chronic intake of some forms of vitamin A can be toxic. Avoid taking supplemental vitamin A as retinol or retinoic acid, and instead use plant-derived vitamin A precursors such as beta-carotene (in addition to other mixed carotenoids). The body can make all the vitamin A it needs from beta-carotene which, unlike animal-derived forms of vitamin A, is not toxic. Beta-carotene is water-soluble and does not accumulate in the body. Dr. Weil suggests 15,000 IU of mixed carotenoids daily, with the best natural sources being from fruits and vegetables, including butternut squash, cantaloupe, carrots, mangoes, pumpkins, spinach, and sweet potatoes.