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Once considered just a potent source of vitamin A, beta-carotene
has gained prominence as a disease-fighting substance. Today,
experts think that beta-carotene, along with the related nutrients
called carotenoids may protect against heart disease and cancer.
What it is
Beta-carotene is part of a larger team of nutrients known
as carotenoids, which are the yellow-orange pigments found
in fruits and vegetables. Because the body converts it to
vitamin A, beta-carotene is sometimes called provitamin A.
However, beta-carotene provides many additional benefits besides
supplying the body with that vitamin.
What Does It Do
An immune system booster and powerful antioxidant, beta-carotene
neutralizes the free radicals that can damage cells and promote
disease. By acting directly on cells, it combats and may even
reverse some disorders. It appears to be most effective when
combined with other carotenoids.
Common Uses
• Acts as a preventive for cancer and heart disease.
• May reverse some precancerous conditions.
• Has cell-protecting properties that may aid in the
treatment of a wide variety of ailments from Alzheimer’s
to male in fertility.
Prevention
Beta-carotene is a celebrated soldier in the war on heart
disease. Results from a survey of more than 300 doctors enrolled
in the Harvard University Physicians’ Health Study revealed
that taking 50 mg (85,000 IU) of beta-carotene a day cut the
risk of heart attack, stroke, and all cardiovascular deaths
in half. Other studies have shown that it can prevent LDL
(“bad”) cholesterol from damaging the heart and
coronary vessels. High levels of beta-carotene may also offer
protection against cancers of the lung, digestive tract, bladder,
breast, and prostate.
Major Benefits
Acting as an antioxidant, beta-carotene has reversed some
precancerous conditions, particularly those affecting the
skin, mucous membranes, lungs, mouth, throat, stomach, colon,
prostate, cervix, and uterus. Further, it has been shown to
inhibit the growth of abnormal cells, strengthen the immune
system, fortify cell membranes, and increase communication
among cells.
One hint of concern did arise, however, about beta-carotene’s
cancer-fighting benefits. In the early 1990s, landmark studies
in Finland and the United States found that male smokers taking
beta-carotene supplements had an increased risk of lung cancer.
Though some found the studies flawed, many experts caution
smokers to maintain adequate beta-carotene levels through
natural food sources, not supplements.
Additional Benefits
As an antioxidant, beta-carotene may be helpful for a wide
range of additional ailments, including Alzheimer’s
disease, chronic fatigue syndrome, male infertility, fibromyalgia,
psoriasis, and a number of vision disorders.
How Much You Need
There is no RDA for beta-carotene, although about 10,000 IU
meets the RDA for vitamin A. Higher doses are needed, however,
to provide the full antioxidant and immune-boosting effects.
If You Get Too Little: Signs of a beta-carotene
deficiency are similar to those of inadequate vitamin A: poor
night vision, dry skin, increased risk of infection, and the
formation of precancerous cells. A deficiency may also increase
your risk of cancer and heart disease. However, vitamin A
deficiencies are rare: Even if you don’t eat fruits
and vegetables or take supplements, you can still meet your
vitamin A needs with eggs, fortified milk, or other foods
that supply it.
If You Get Too Much: It’s almost impossible
to get too much beta-carotene: The body discards what it doesn’t
process. If you ingest high levels (over 100,000 IU a day)
your palms and soles may turn a harmless orange tone, which
will disappear when you lower the dose.
How To Take It
Dosage: Beta-carotene is probably most effective
when combined with other carotenoids in a mixed carotenoid
formula. Most people benefit from 25,000 lU (15 mg) of mixed
carotenoids a day. Those at high risk for cancer can take
up to 50,000 lU (30 mg) twice a day.
Guidelines For Use: Take supplements with
meals. No adverse effects have been noted in pregnant or nursing
women taking up to 50,000 10 a day.
Other Sources
Carrots are a rich source of beta-carotene, as are other yellow,
orange, and red fruits and vegetables, from sweet potatoes
to cantaloupe. Green vegetables, such as broccoli, spinach,
or lettuce, are also beneficial; the darker the green, the
more beta-carotene they contain.
Caution!
• Consult your physician before using beta-carotene
if you have a sluggish thyroid (hypothyroidism), kidney or
liver disease, or an eating disorder.
• Many experts recommend that smokers, particularly
those who consume large amounts of alcohol, avoid beta-carotene
supplements.
Shopping Hints
Purchase beta-carotene in combination with other carotenoids,
such as lycopene, alpha-carotene, cryptoxanthin, zeaxanthin,
and lutein. These combination formulas are an effective and
economical way to boost your antioxidant levels.
Latest Findings
Beta-carotene may help protect against many types of cancer,
but in smokers, it may actually increase the risk of lung
cancer. Recent studies show that this surprising effect seems
strongest in men who smoke at least 20 cigarettes daily and
increases further when alcohol intake is “above average.”
(Interestingly, former smokers do not appear to be at heightened
risk.) One theory is that smokers generally have low vitamin
C levels, and this imbalance causes beta-carotene to heighten,
rather than decrease, free-radical formation.
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