Beta Carotene Health Article

Supplemental beta carotene

Beta carotene supplements are inexpensive and readily available over-the-counter. They are available as pills, powders, and oils and they vary greatly in potency. Some supplements contain a mixture of carotenoids. There is a major problem with shelf life stability for beta carotene, as it "oxidizes" quickly when in pure form. When buying a supplement of it, shelf life stability or the presence of such stabalizers as vitamin E can guarantee biological activity of the capsule.

Supplemental intake of beta carotene probably should not exceed 3–15 mg per day. Common preparation of supplemental beta carotene include:

• 30- or 60-mg capsules
• 5,000-, 10,000-, or 25,000-IU capsules
• 10,000- or 25,000-IU tablets

A typical dosage of beta carotene for treating cancer is 75,000–150,000 IU daily. Absorption of beta carotene in nutritional supplements can be 70% or more. There is no established maximum daily intake for beta carotene.

Some common beta carotene nutritional supplements include:

• A-Caro-25
• B-Caro-T
• Biotene
• Caroguard
• Caro-Plete
• Dry Beta Carotene
• Lumitene
• Marine Carotene
• Mega Carotene
• Oceanic Beta Carotene
• Superbeta Carotene
• Ultra Beta Carotene

Manufacturers often supplement food with beta carotene. One study showed that bakery products enriched with beta carotene increased beta carotene levels in the blood.

Measuring beta carotene

A recommended dietary allowance (RDA) for beta carotene has not been established and most foods are not labeled as to vitamin A content. There are two incompatible systems for quantifying beta carotene. IUs are used most often for nutritional labeling:

• 1 IU equals 0.6 µg of all-trans beta carotene
• 3.33 IU of all-trans beta carotene, 2 µg, is equal to 1 µg of all-trans retinol (vitamin A)
• 5,000 IU equals 3 mg of beta carotene, the RDA for vitamin A
• 1 IU equals 1.2 µg of other provitamin A carotenoids

The second system uses retinol equivalents (RE):

• 1 RE equals 1 µg of all-trans retinol
• 1 RE equals 6 µg of all-trans beta carotene
• 1 RE equals 12 µg of other provitamin A carotenoids

Precautions

Antioxidants such as beta carotene often work together with other antioxidants and an excess or deficiency of one can inhibit the other. The Food and Nutrition Board of the Institute of Medicine does not recommend beta carotene supplementation except in cases of vitamin A deficiency.

Pregnant and nursing mothers should limit their intake of supplemental beta carotene to 6 mg per day or less.

Side effects

Even long-term high-dosage use of supplemental beta carotene appears to be non-toxic. Daily doses of 30 mg or more over a long period may cause carotenosis (carotenodermia), a yellowing of the skin, which is harmless and reversible. In contrast, very high daily doses of vitamin A are very dangerous and damage the liver and other organs, as well as provoke hair loss).

Interactions

Drugs and other substances that may interfere with beta-carotene absorption include:

• Cholestyramine
• Colestipol
• mineral oil
• Olestra
• Orlistat
• pectin

The absorption of luteine, another carotenoid antioxidant, may be reduced if taken in conjunction with beta carotene.

BOOKS

American Institute for Cancer Research. Nutrition and Cancer Prevention: New Insights into the Role of Phytochemicals. New York: Kluwer Academic/Plenum Publishers, 2001.

Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium, and Carotenoids. Washington: National Academy Press, 2000.

PDR for Nutritional Supplements. Montvale, NJ: Thomson PDR, 2001.

PERIODICALS

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"Disheartening Study." Better Nutrition 65, no. 9 (September 2003): 32.

Heinrich, U., et al. "Supplementation with Beta-carotene or a Similar Amount of Mixed Carotenoids Protects Humans from UV-induced Erythema." Alternative Medicine Review 8, no. 2 (May 2003): 202–203.

"Incidence and Mortality Following Alpha-tocopherol and Beta-carotene Supplementation: A Postintervention Follow-up." Journal of the American Medical Association 290, no. 4 (July 23, 2003): 476–85.

Quilez, Joan, et al. "Bakery Products Enriched with Phytosterol esters, [Alpha]-Tocopherol and [Beta]-Carotene Decrease Plasma LDL-Cholesterol and Maintain Plasma [Beta]-Carotene Concentrations in Normocholesterolemic Men and Women." Journal of Nutrition 133, no. 10 (October 2003): 3103.

Russell, R. M., et al. "The Enigma of Beta-Carotene in Carcinogenesis: What Can Be Learned From Animal Studies." Journal of Nutrition 134, no. 1 (2004): 262S–268S.

"What's Up Doc? Getting to the Root of Carrots." Environmental Nutrition 26, no. 9 (September 2003): 8.

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