vitamin A, b-carotene, provitamin A
Beta-carotene belongs to a group of provitamins which are related to vitamin A, called carotenoids. Their reddish-violet pigment imparts color to plants, which can be seen in some of its food sources such as carrots, sweet potatoes and apricots.
Beta-carotene is a precursor of vitamin A. Beta-carotene is fat soluble, but does not accumulate in the body to toxic levels like vitamin A can. Also, beta-carotene is an important antioxidant with a significant role in maintaining the health of cells.
Beta-carotene and vitamin A play an important part in the reproductive process and in maintaining healthy skin, eyes, and immune system.
See vitamin A for more information.
Beta-carotene and other carotenoids provide approximately 50 percent of vitamin A in the diet. It also provides antioxidant functions that help reduce the damage in your body from free radicals.
Taking beta-carotene is a safe way of ensuring adequate levels of vitamin A while avoiding any toxic side effects.
Malnutrition is a leading cause of beta-carotene (and vitamin A) deficiency.
Malnutrition is a leading cause of vitamin A deficiency in many parts of the world. Malabsorption syndromes, such as lactose intolerance, tropical and nontropical sprue, and cystic fibrosis, may deplete all four fat-soluble vitamins, A, D, E, and K.
Women who are pregnant or breastfeeding may need to take vitamin supplements, but must consult a physician before doing so.
Increased levels of beta-carotene are claimed to reduce the risk of certain types of cancer such as prostate cancer, heart disease, and stroke. However, studies neither support not reject these claims.
One study has pointed to an increased risk of lung cancer among smokers who increase their intake of beta-carotene.
There is no Recommended Daily Allowance (RDA) or Dietary Reference Intake (DRI) for this vitamin. However, the recommended amounts (Recommended Daily Intake) are indicated below in International Units (IUs).
300 (1,000 IU)
400 (1,321 IU)
600 (2,000 IU)
900 (3,000 IU)
700 (2,310 IU)
750 (2,500 IU)
1,200 (4,000 IU)
770 (2,565 IU)
1,300 (4,300 IU)
400 (1,320 IU)
500 (1,650 IU)
Liver, beef, cooked, 3 ounces
Liver, chicken, cooked, 3 ounces
Milk, fortified, skim, 1 cup
Cheese, cheddar, 1 ounce
Milk, whole (3.25% fat), 1 cup
Egg substitute, 1/4 cup
*IU = International Unit.
**These amounts are for vitamin A.
In general, increasing fruits and vegetables in the diet provides good sources of beta-carotene. Fruits and vegetables that are red, orange, deep-yellow, and some dark-green typically are high in carotenoids.
Signs of vitamin A deficiency include night blindness, fatigue, skin disorders, and a weakened immune system. Xerophthalmia (abnormal dryness and thickening of the conjunctiva and cornea) results from severe vitamin A deficiency and is a leading cause of blindness in the underdeveloped parts of the world.
Beta-carotene is considered safe and does not appear to be toxic in large doses. However, high doses over a long period of time can lead to a condition known as carotenemia in which the skin becomes yellowish orange.
An excess of beta-carotene can pose a risk in individuals who cannot convert beta-carotene to vitamin A. This can be the case with individuals who suffer from hypothyroidism.
There are no known contraindications to beta-carotene.
Orlistat, a new drug for weight loss, has been shown to decrease absorption of both beta-carotene and vitamin E. It is unknown at this time if it reduces absorption of vitamin A.
Patients taking Accutane (isotretinoin), Soriatane (acitretin), or Tegison (etretinate) are advised against using either vitamin A or beta-carotene supplements while on the medication.
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