|| b-carotene, Trans-beta Carotene, Provitamin A,
Beta-carotene, derived from the Latin name for carrot, belongs to a family of
natural chemicals known as carotenes or carotenoids. Widely found in plants,
carotenes give yellow and orange fruits and vegetables their rich colors.
Beta-carotene is also used as a coloring agent for foods such as margarine.
Beta-carotene is converted to vitamin A (retinol) by the body. While
excessive amounts of vitamin A in supplement form can be toxic, the body will
only convert as much vitamin A from beta-carotene as it needs. This feature
makes beta-carotene a safe source of vitamin A.
Like all other carotenoids, beta-carotene is an antioxidant. Consuming foods
rich in beta-carotene appears to protect the body from damaging molecules called
free radicals. Free radicals cause damage to cells through a process known as
oxidation, and over time, such damage can lead to a variety of chronic
illnesses. Some studies suggest that dietary intake of beta-carotene may reduce
the risk of two types of chronic illness—heart disease
and cancer. Supplementation, however, is more controversial; see discussion in
the section that follows.
Population-based studies suggest that groups of people who eat 4 or more
daily servings of fruits and vegetables rich in beta-carotene may have less of a
chance of developing heart disease or cancer. Interestingly, however, other
studies indicate that people who take beta-carotene supplements may actually be
at an increased risk for such conditions. Researchers speculate that multiple
nutrients, consumed in a healthy, balanced diet may be more effective than
beta-carotene supplements alone in protecting against cancer and heart disease.
Studies suggest that high doses of beta-carotene may decrease sensitivity to
the sun. This is particularly helpful for people with skin conditions caused by
sunlight exposure, such as erythropoietic protoporphyria, a condition
characterized, in part, by development of hives or eczema upon exposure to the
sun. Under the guidance of an appropriate health care professional, the oral
supplement dose of beta-carotene is slowly adjusted over a matter of weeks and
exposure to sunlight gradually increased.
Because people with scleroderma, a connective-tissue disorder characterized
by hardened skin, have low levels of beta-carotene in their blood, some
researchers speculate that beta-carotene supplements may be beneficial for those
with the condition. Due to methodological flaws in the studies that have been
conducted to date, however, research has not confirmed this theory. At this
time, it is best to obtain beta-carotene from dietary sources and avoid
supplementation until more information is available.
The richest sources of beta-carotene are yellow, orange, and green leafy
fruits and vegetables (such as carrots, spinach, lettuce, tomatoes, sweet
potatoes, broccoli, cantaloupe, and winter squash). In general, the greater the
intensity of the color of the fruit or vegetable, the more beta-carotene it
|Dosage and Administration|
Beta-carotene supplements are available in both capsule and gel forms.
Beta-carotene is fat-soluble and, therefore, should be taken with meals
containing at least 3 g of fat to ensure absorption.
- For children younger than 14 with erythropoietic protoporphyria (see
Treatment section for brief
description of this condition), 30 to 150 mg per day (50,000 to 250,000 IU) in
single or divided oral doses for 2 to 6 weeks is recommended. The supplement may
be mixed with orange or tomato juice to facilitate administration. In the case
of this sun-sensitive condition, a doctor can measure blood levels of
beta-carotene and adjust the dose accordingly.
- For general health, 15 to 50 mg (25,000 to 83,000 IU) per day is
- For adults with erythropoietic protoporphyria, 30 to 300 mg (50,000 to
500,000 IU) per day for 2 to 6 weeks is recommended. A healthcare practitioner
can measure blood levels of beta-carotene and adjust the dose accordingly.
Beta-carotene offers protection from cancer only when other important
antioxidants, including vitamins C and E are present in the diet. Since
beta-carotene may increase the risk of heart disease and cancer in those who
smoke or drink heavily, this supplement should be used with caution, if at all,
by heavy smokers or drinkers.
Although beta-carotene affords protection from sunlight for people with
certain skin sensitivities, it does not protect against sunburn.
Side effects from beta-carotene include:
- Skin discoloration (yellowing that eventually goes
- Loose stools
- Joint pain
|Pregnancy and Breastfeeding|
While animal studies indicate beta-carotene is not toxic to a fetus or a
newborn, there are no human studies to confirm these findings. The supplement
may pass into breast milk but no information on the safety of its use during
breastfeeding has been reported. Therefore, while pregnant or breastfeeding,
beta-carotene supplements should only be used under the guidance of a physician
or other appropriately trained specialist.
Side effects in children are the same as those seen in
Side effects in older adults are the same as younger
|Interactions and Depletions|
People taking the following medications should avoid beta-carotene
Cholestyramine, Colestipol, Probucol
Cholestyramine and probucol, medications used to lower cholesterol, can lower
blood concentrations of dietary beta carotene by 30% to 40%, according to a
3-year trial in Sweden. Colestipol, a cholesterol-lowering medication similar to
cholestyramin, may also reduce beta-carotene levels.
Beta-carotene and orlistat, a weight loss medication, should not be taken
together because orlistat can reduce the absorption of beta-carotene by as much
as 30%, thereby reducing the amount of this nutrient in the body. Those who must
take both orlistat and beta-carotene supplements should separate the time
between taking the medication and the supplements by at least 2 hours.
In addition to these medications, mineral oil (used to treat constipation)
may lower blood concentrations of beta-carotene and ongoing use of alcohol may
interact with beta-carotene, increasing the likelihood of liver
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|Review Date: March 2001|
|Reviewed By: Participants in the review process include: David Winston, Herbalist,
Herbalist and Alchemist, Inc., Washington, NJ; Jacqueline A. Hart, MD,
Department of Internal Medicine, Newton-Wellesley Hospital, Harvard University
and Senior Medical Editor Integrative Medicine, Boston,
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