Vitamin C or L-Ascorbic Acid is not manufactured by the body. It must
be obtained through diet or supplementation. It is a water soluble
vitamin found in the juices of fruits and vegetables and readily
leaches into the cooking water of boiled foods. It is very sensitive to
oxidation and is destroyed whenever foods are cut or torn which exposes
the cells to air. Alkalies such as baking soda or antacids destroy
ascorbic acid.
Vitamin C is a very important antioxidant and is required for at least
300 metabolic functions in the human body. This includes tissue growth
and repair, adrenal gland function, and healthy gums. It also aids the
production of anti-stress hormones and interferon which is an important
immune-system protein. It must also be present for the metabolism of
folic acid, tyrosine and phenylalanine. Taking vitamin C can reduce the
symptoms of asthma.
Ascorbic acid protects against the harmful effects of pollution, helps
prevent cancer, protects against infection, and enhances immune system
function. It increases the absorption of iron and can combine with
toxic substances, like certain heavy metals, and render them harmless
and allow them to be eliminated from the body. Very large doses of
vitamin C may even render the venom of the black widow spider harmless.
This vitamin may also reduce levels of LDL (the bad cholesterol) while
it increases levels of HDL (the good cholesterol) and lower high blood
pressure to help prevent atherosclerosis. It is essential for the
formation of collagen. Collagen is a protein that forms the basis for
connective tissue, the most abundant tissue in the body. Collagen binds
muscle cells together, gives support and maintains shape in
intervertebral discs and eustachian tubes, and provides movement in
joints. Vitamin C protects against abnormal blood clotting and
bruising. It may reduce the risk of cataracts and promotes healing of
wounds and burns.
Vitamins C works in concert with both vitamin E and beta-carotene.
Taking these vitamins together allow them to repotentiate each other
and may counter potential adverse effects of taking them separately.
Vitamin E works to scavenge dangerous free radicals in cell membranes,
while vitamin C scavenges free radicals in biologic fluids. These
vitamins reinforce and extend the antioxidant activity of the other.
Ascorbic acid has a role in amino acid metabolism and hormonal
synthesis. It contributes to the formation of tyrosine (the precursor
for the neurotransmitters epinephrine and norepinephrine). During
periods of stress these hormones are mobilized, and the small stores of
ascorbic acid in the adrenal glands are depleted. Therefore, vitamin C
may help the body deal more effectively with stress. Tryptophan is
converted to 5-hydroxytryptophan in the presence of vitamin C and is
decarboxlated to form the neurotransmitter serotonin.
CANCER: Cancer risk is reduced by the antioxidant characteristics of
vitamin C. Researchers at Trinity College in Dublin, Ireland found that
free-radical activity damages DNA, which might initiate carcinogenic
changes in colonic mucosa. Vitamin C suppresses this damage and limits
adenomatous polyp growth in patients with colorectal cancer. This
vitamin acts as a cytotoxic agent in cancerous cells to reverse
chemically-transformed cells back to a normal phenotype. Vitamin C,
together with beta-carotene, reverses cervical dysplasia, leukoplakia,
and gastric metaplasia.
CARDIOVASCULAR DISEASE: A study at the University of California, Los
Angeles, compared heart disease mortality rates in individuals with the
highest and lowest vitamin C intakes and found that regular
supplementation with vitamin C reduced the mortality rate from
cardiovascular disease by 45%.
DIABETES: Ascorbic acid may help regulate insulin action in diabetics
according to a study conducted at the National Institutes of Health.
The study indicates that ascorbic acid participates in insulin
regulation by inhibiting glucose-induced insulin release in pancreatic
islets.
IMMUNE SYSTEM: A marginal ascorbic acid deficiency results in
compromised immune system function according to a study from USDA
Agriculture Research Service in San Francisco and UCLA School of Public
Health in Los Angeles. This was despite the absence of clinical
deficiency symptoms. Moreover, researchers at Arizona State University
in Tempe report that high intakes of vitamin C stimulate the immune
system response by degrading and detoxifying histamine and might
indirectly enhance neutrophil chemotaxis.
COMMON COLD: Finnish researches reviewed current research on ascorbic
acid and the common cold. They found that most studies report the
vitamin to have only a small effect on cold prevention. However, the
studies consistently show this vitamin helps reduce a cold's duration
and severity. Vitamin C supplements given in therapeutic doses (1 to 8
grams/day) at the onset of a cold reduce the duration of cold episodes
by as much as 48%.
VISION: Levels of vitamin C in the eye are 20 to 70 times greater than
that found in plasma and other tissues. This vitamin plays a key role
in proper ocular function by protecting the eye against light-induced
loss of retinal pigment, epithelial cells, and photoreceptor cells. It
also eliminates O2 from the lens and protects against UV radiation.
There is some evidence that links higher intakes of this vitamin with a
reduced risk of age-related macular degeneration.
Low intakes of this vitamin may increase the risk for developing
cataracts. Low levels to none are found in cataractous lenses, while
human lenses with senile cataracts have increased levels of free
radicals. It is unknown whether these associations are the cause or
result of cataracts. In vitro studies have shown that ascorbic acid may
benefit glaucoma in the human eye.
CAUTIONS: Do not take aspirin and large doses of standard ascorbic acid
together. Doing so may lead to stomach irritations, possibly
contributing to ulcer formation. If you take aspirin regularly, use a
buffered form of vitamin C, and take it separately from the aspirin.
If pregnant, take no more than 5,000 mg of ascorbic acid per day. A
developing infant may become dependent on this supplement and develop
scurvy when deprived of the accustomed megadoses after birth.
Avoid using chewable forms of this supplement, as these can damage tooth enamel.
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