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This vitamin is probably better known and more widely used
than any other nutritional supplement. But even if you think
you’re familiar with vitamin C, read on. You may be
surprised to discover exactly how versatile and health-enhancing
this nutrient truly is.
What Is It
As early as 1742 lemon juice was known to prevent scurvy,
a debilitating disease that often plagued long-distance sailors.
But not until 1928 was the healthful component in lemon juice
identified as vitamin C. Its anti-scurvy, or antiscorbutic,
effect is the root of this vitamin’s scientific name
ascorbic acid. Today, interest in vitamin C is based less
on its ability to cure scurvy than on its potential to protect
cells. As the body’s primary water-soluble antioxidant,
vitamin C helps fight damage caused by unstable oxygen molecules
called free radicals, especially in those areas that are mostly
water, such as the interior of cells.
What Does It Do
Vitamin C is active throughout the body. It helps strengthen
the capillaries (the tiniest blood vessels) and cell walls
and is crucial for the formation of collagen (a protein found
in connective tissue). In these ways, vitamin C prevents bruising,
promotes healing, and keeps ligaments (which connect muscle
to bone), tendons (which connect bone to bone), and gums strong
and healthy. It also aids in producing hemoglobin in red blood
cells and assists the body in absorbing iron from foods.
Common Uses
• Enhances immunity.
• Minimizes cold symptoms; shortens duration of illness.
• Speeds wound healing.
• Promotes healthy gums.
• Treats asthma.
• Helps prevent cataracts.
• Protects against some forms of cancer and heart disease.
Prevention
As an antioxidant, vitamin C offers protection against cancer
and heart disease; several studies have shown that low levels
of this vitamin are linked to heart attacks. In addition,
vitamin C may actually lengthen life. In one study, men who
consumed more than 300 mg of vitamin C a day (from food and
supplements) lived longer than men who consumed less than
50 mg a day.
Another study found that over the long term, vitamin C supplements
protect against cataracts, a clouding of the lens of the eye
that interferes with vision. Women who took vitamin C for
10 years or more had a 77% lower rate of early “lens
opacities,” the beginning stage of cataracts, than women
who didn’t use supplements.
Additional Benefits
Does vitamin C prevent colds? Probably not, but it can help
lessen symptoms and may shorten the duration of this illness.
In a 1995 analysis of studies exploring the connection between
vitamin C and colds, the researchers concluded that taking
1,000 to 6,000 mg a day at the onset of cold symptoms reduces
the cold’s duration by 21%, about one day. Other studies
have shown that vitamin C helps elderly patients fight severe
respiratory infections. Vitamin C also appears to be a natural
antihistamine. High doses of the vitamin can block the effect
of inflammatory substances produced by the body in response
to pollen, pet dander, or other allergens.
The vitamin is an effective asthma remedy as well. Numerous
studies have found that vitamin C supplements helped prevent
or improve asthmatic symptoms. For people with type 1 diabetes,
which interferes with the transport of vitamin C into cells,
supplementing with 1,000 to 3,000 mg a day may prevent complications
of the disease, such as eye problems and high cholesterol
levels.
How Much You Need
The RDA for vitamin C for men and women is 60 mg a day (for
smokers, it’s 100 mg) However, even conservative experts
think an optimal intake is at least 200 mg a day, and they
recommend higher doses for the treatment of specific diseases.
If You Get Too Little: You’d have to
consume less than 10 mg a day to get scurvy, but receiving
less than 50 mg of vitamin C a day has been linked with an
increased risk of heart attack, cataracts, and a shorter life.
If You Get Too Much: Large doses of vitamin
C (more than 2,000 mg a day) can cause loose stools, diarrhea,
gas, and bloating; all can be corrected by reducing your daily
dose. At this level, the vitamin may interfere with the absorption
of copper and selenium, so make sure you consume enough of
these minerals in foods or supplements.
How To Take It
Dosage: For general health: Get 500 mg of vitamin
C a day through foods and supplements. For the treatment of
various diseases: Depending on the condition, 1,000 to 6,000
mg a day may be appropriate.
Guidelines For Use: Large amounts are best
absorbed in 1,000 mg doses, taken with meals throughout the
day. The vitamin works very well when combined with other
antioxidants, such as vitamin E.
Other Sources
Citrus fruits and juices, broccoli, red peppers, dark greens,
strawberries, and kiwifruits are all good sources of vitamin
C.
Caution!
• Don’t take more than 500 mg a day if you have
kidney stones, kidney disease, or hemochromatosis, a genetic
tendency to store excess iron (vitamin C enhances iron absorption).
• Vitamin C can distort the accuracy of medical tests
for diabetes, colon cancer, and hemoglobin levels. Let your
doctor know if you’re taking it.
Shopping Hints
Don’t spend extra money on specialized vitamin C products
(such as esterified C). There’s no evidence that they
are more efficiently absorbed than plain old ascorbic acid.
Latest Findings
• Vitamin C may help prevent reblockage (restenosis)
of arteries after angioplasty (an alternative to bypass surgery).
A study of 119 angioplasty patients found that restenosis
occurred in just 24% of those who took 500 mg of vitamin C
a day for four months, compared with 43% of those who did
not take the vitamin.
• In addition to being an antioxidant, vitamin C helps
the body recycle other antioxidants. In one study, vitamin
E concentrations were 18% higher in those who got more than
220 mg of vitamin C a day, compared with people who got 120
mg or less.
• Vitamin C recently came under attack when a small
test-tube study found that it may cause genetic damage, potentially
increasing the risk of cancer. But scientists have since identified
serious flaws in the study. Many better studies show that
vitamin C provides numerous benefits, including preventing
certain cancers.
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