DESCRIPTION/FUNCTION

• Beta-Carotene is classified as a member of the carotenoid family. There are more than 500 different carotenoids, including other carotenes, xanthophylls, and lycopene. Beta-carotene is a precursor (provitamin A) to retinol (preformed vitamin A). It is converted to vitamin A in the liver as needed. As a source of vitamin A, beta-carotene is: essential for normal growth, development, and maintenance of epithelial tissue; essential to the integrity of night vision; helps provide for normal bone development; influences normal tooth formation; necessary for wound healing.

DRI (RDA or AI for Adults)

• None.
• 12 mcg = 1 RAE (Retinol Activity Equivalents).
• About 14% of beta-carotene is absorbed. (Previously believed 33%.)

MAJOR SOURCES

• Yellow and dark green vegetables (carrots, squash, peas, broccoli, sweet potatoes, peppers, spinach, ‘green’ lettuce), orange fruits.

MAINTENANCE/THERAPEUTIC RANGE

• 10 mg to 50 mg (2,774 IU to 13,875 IU).
• To convert mg to IU: multiply by 1,000, divide by 12, then multiply by 3.33.
• See Vitamin A.
• Avoid synthetic beta-carotene.

POSSIBLE THERAPEUTIC APPLICATIONS

• Cancer (breast, colorectal, gastric, ovarian, prostate)
• Macular degeneration

COMMENTS

• Determining the effectiveness of beta-carotene is difficult, since most of the research is epidemiological. Foods that are high in it often also contain lutein, lycopene, zeaxanthin, and hundreds of other carotenoids, as well as vitamins and other ingredients. Research using only isolated beta-carotene has been disappointing. Use beta-carotene supplements that come from natural sources (usually Dunaliella salina algae), which therefore also contain a mix of the other carotenoids.

CAUTIONS

• High doses can cause yellow or orange skin pigmentation.