Beta
Carotene
DESCRIPTION:
Beta carotene belongs to a natural
chemical family known as carotenes or carotenoids.
Widely found in plants, carotenoids give fruits, vegetables, and
other plants their distinctive colours. Beta carotene is
significant from a nutritional perspective, because the body can
easily transform it to Vitamin
A. It is the best source of vitamin A, since the body will
only make as much as is necessary. Vitamin A supplements, on the
other hand, can be toxic when taken excessively. A variety of
health benefits have been documented for food sources of beta
carotene.
For nutritional purposes, the
recommended dosage of beta carotene is the amount needed to
obtain the optimal amount of vitamin A. For example, three mg
(5000 IU) of beta carotene supplies 5000 IU of vitamin A. The
recommended amount of vitamin A varies with age and sex. Refer
to Vitamin
A for further information.
Antioxidant:
Beta carotene possesses valuable antioxidant activity which may
help to protect against free radical damage initiated by
sunlight, pollution etc.
Heart disease:
It has been documented that beta carotene can protect against
heart disease (1).
Eye Health:
Dietary beta carotene can slow the progression of cataracts. In
addition, it may also prevent macular degeneration, which is
associated with fine visual perception (2,3).
Osteoarthritis:
Dietary beta carotene may also slow the progression of
osteoarthritis (4).
Beta carotene has been found to be
very safe when taken at recommended dosages. Side effects that
have been reported from beta carotene overdose are d iarrhoea
and a yellowish tinge to the hands and feet. These minor
problems disappear once consumption is halted or decreased.
Smokers are advised not to take
individual high level beta carotene supplements.
Those who work with or have been
exposed to asbestos are advised to avoid beta carotene
supplements.
INTERACTIONS
AND CONTRA-INDICATIONS
Several drugs may interact with
beta-carotene. Colchicine and methotrexate decrease absorption
of beta carotene. If one is taking a cholesterol-lowering drug
such as colestipol or cholestyramine, he/she may require extra
beta carotene.
Good sources of beta-carotene are
dark green and orange-yellow vegetables. These include carrots,
sweet potatoes, squash, spinach, romaine lettuce, broccoli,
apricots, and green peppers.
REFERENCES:
1. Kohlmeier L and Hastings SB.
Epidemiologic evidence of a role of carotenoids
in cardiovascular disease prevention. Am J Clin Nutr 62(suppl.):
1370S-1376S, 1995.
2. Carson C, Lee S, De Paola C, et al. Antioxidant intake and
cataract in the Melbourne Visual Impairment Project. Am J
Epidemiol 139: S18, 1994.
3. Seddon JM, Ajani UA, Sperduto RD, et al. Dietary carotenoids,
vitamins A, C, and E, and advanced age-related macular
degeneration. JAMA 272: 1413-1420, 1994.
4. McAlindon TE, et al. Do antioxidant micronutrients protect
against the development and progression of knee OA? Arth Rheum
39: 648-656, 1996.
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