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The Eclectic Physician
Vitamin and Mineral Information
Carotenes
The information on this page compiled by
Beth Burch N.D.
Index
(click on the keywords)
Function
Carotenes are a large group of intense red and yellow
pigments found in all plants that photosynthesize. They are vital for the
process of photosynthesis and also protect the plant against damage from
the free radicals produced during photosynthesis. In animals and humans,
carotenes function as antioxidants and some like beta-carotene can be converted
to vitamin A in the body. Over 600 different carotene compounds have been
identified and many have promising cancer preventing effects. Interestingly,
the best benefits appear to come from food sources of the carotenes, rather
than from isolated compounds in supplement form. Carotene deficiency will
result in vitamin A deficiency if there is no other source of vitamin A
in the body (See vitamin A), and deficiency is also linked with increased
risk of a variety of cancers, including skin, lung, cervix and gastrointestinal
cancers. Deficiency of lutein increases the risk of cataracts and macular
degeneration. Excess intake of carotenes can result in an ac cumulation
in the skin giving an orange appearance , but does not cause toxicity like
vitamin A.
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Forms
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Common supplements include:
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Beta-carotene
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Mixed carotenes
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Lycopene
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Lutein
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Food Sources
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Alpha, beta and gamma carotene are found in large amounts in leafy greens,
carrots, sweet potatoes, squash, apricots and yams. Lycopenes are high
in tomatoes, carrots, green peppers, apricots and pink grapefruit. Lutein
is high in leafy greens, corn, carrots, tomatoes and fruits.
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Dosage
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Recommended Daily Allowance (RDA)
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There is no RDA for carotenes. For vegetarians, beta-carotene will be converted
to supply vitamin A in the body. The amount of beta-carotene needed to
supply the RDA of vitamin A in an adult is 5 mg or 8300 IU per day.
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Optimal Supplementation
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Beta-carotene- 10,000-25,000 IU daily
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Lycopene- At least 6 mg per day
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Lutein- At least 6 mg per day
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Since the carotenes work together, the best way to get good amounts of
all of them is to consume plenty of fresh vegetables and fruits, especially
leafy greens, dark orange vegetables and fruits and tomatoes.
Treatment
of Health Conditions
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Beta-carotene- 25,000-100,000 IU per day
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Conditions used
for
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HIV (1, 2, 5)
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Preventing vaginal yeast infections (3)
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Cancer prevention (4, 6, 7, 11)
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Immune enhancement (9)
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Psoriasis (10)
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Preventing cataracts and macular degeneration- lutein (12)
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Side effects
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Orange color of skin (especially palms and soles) may occur with high intake
of yellow -orange carotenes. This is more likely with deficiency of zinc,
vitamin C or thyroid hormone.
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High intake of carotenes may increase cholesterol and triglyceride levels
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Contraindications
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Interactions
with other nutrients
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High doses of beta-carotene may deplete vitamin E
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Zinc, vitamin C and protein are needed for the conversion of carotenes
to vitamin A
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Interactions
with medications and herbs
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References
1. Omene JA et al, Serum beta-carotene deficiency in HIV-infected
children, J Natl Med Assoc 1996;88(12):789-93
2. Fryburg DA et al, The effect of supplemental beta-carotene on immunologic
indices in patients with AIDS: a pilot study, Yale J Biol Med 1995;68(1-2):19-23
3. Mikhail MS et al, Decreased beta-carotene levels in exfoliated vaginal
epithelial cells in women with vaginal candidiasis, Am J Reprod Immunol
1994;32(3):221-5
4. Rock CL et al, Carotenoids: biology and treatment, Pharmacol Ther
1997;75(3):185-97
5. Sappey C et al, Vitamin, trace element and peroxide status in HIV
seropositive patients: asymptomatic patients present a severe beta-carotene
deficiency, Clin Chim Acta 1994 Oct 14;230(1):35-42
6. Smith TA, Carotenoids and cancer: prevention and potential therapy,
Br J Biomed Sci 1998;55(4):268-75
7. Zhang S et al, Dietary carotenoids and vitamins A, C, and E and
risk of
breast cancer, J Natl Cancer Inst 1999;91(6):547-56.
8. Yang Y, Carotenoid analysis of several dark-green leafy vegetables
associated with a lower risk of cancers, Biomed Environ Sci 1996;9(4):386-92
9. Santos MS et al, Natural killer cell activity in elderly men is
enhanced by beta-carotene supplementation, Am J Clin Nutr;64(5):772-7
10. Naldi L et al, Dietary factors and the risk of psoriasis. Results
of an Italian case-control study, Br J Dermatol 1996;134(1):101-6
11. Sengupta A et al, The anti-carcinogenic role of lycopene, abundantly
present in tomato, Eur J Cancer Prev 1999;8(4):325-30
12. Bone RA et al, Distribution of macular pigment componets, zeazanthin
and lutein,in human retina, Methods Enzymol 1992;213:360-66
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* The information presented in this web site is intended to inform and educate.
It is not intended replace a qualified medical practitioner to diagnose or treat medical conditions.
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