Megavitamin therapy is the use of large
doses of vitamins, often many times greater than the recommended
dietary allowance in the attempt to prevent or treat diseases.
Megavitamin therapy is typically used in alternative medicine by
practitioners who call their approach "orthomolecular medicine",
but also used in mainstream medicine for "exceedingly rare"
genetic conditions that respond to megadoses of vitamins.
Nutrients may be useful in preventing and
treating some illnesses, but the conclusions of medical research are
that the broad claims of disease treatment by advocates of
megavitamin therapy are unsubstantiated by the available evidence. It
is generally accepted that doses of any vitamin greatly in excess of
nutritional requirements, will result either in toxicity or in the
excess simply being metabolized - evidence in favor of vitamin
supplementation supports only doses in the normal range. Critics have
described some aspects of orthomolecular medicine as food fadism or
even quackery. Research on nutrient supplementation in general
suggests that some nutritional supplements might be beneficial, and
that others might be harmful.
That's MEGAVITAMIN therapy, but what
about claims that optimum doses that should be used in both
prevention and treatment should range from very small to very large,
depending on what is being treated. The same is true for ANY
medication...larger doses aren't always better! One thing that IS
known is that vitamins may have effects which appears to be unrelated
to their properties as vitamins. For example, see this report from
the National Cancer Institute on Vitamin C.
Also worth reading is a report from a
University of California, Berkeley biochemist that high doses of
some vitamins could play a big role in the treatment of disease and
perhaps slow the effects of aging.
There are the toxic side effects of
megadose vitamin therapy, usually self-prescribed regimens taken by
individuals and sometimes they wind up sick. It's estimated that
only about 7 percent of the estimated 40 million Americans who
regularly take vitamins do so under the guidance of a physician.
Toxic effects of megadoses have been
discovered for most vitamins, including some, like vitamins A and C.
Even some of the water-soluble B vitamins, commonly thought to be
nontoxic in any amount because they are rapidly cleared from the
body, are now known to cause devastating effects in megadose
quantities.
Further, in some patients who are under
drug treatment for an illness, taking megadoses of vitamins can
interfere with their treatment. By the way, megadoses a re defined as
10 or more times the recommended daily amount.
The problem is that many times some
nutritionists speak of hidden vitamin deficiencies that could cause a
wide range of common symptoms and for chronic or incurable problems,
they make extravagant promises. People with arthritis, diabetes,
heart disease or cancer are, because of their condition, are often
easy targets of such claims. As a result, it is always best to avoid
megadoses unless prescribed by a physician. It's also a good idea to
tell your physician if asked about medications about any supplements
you are taking.
Although excessive amounts of water
soluable vitamins quickly leave the body they can sometimes cause
adverse effects. For example, Niacin megadoses are associated with
side effects that include flushing of the face, neck and chest,
abnormal heart rhythms, itching, headache, cramps, nausea and
vomiting, diarrhea, abnormally low blood pressure, fast heart beat,
and elevated blood sugar. In large doses niacin can cause dry skin
and abnormal skin pigmentation, aggravate peptic ulcers and damage
the liver.
Large doses of Vitamin B6 have been known
to produce severe neurological problems including numbness,
difficulty walking, sharp pains and loss of normal reflexes.
Fortunately, the symptoms usually disappear after megadoses were
stopped, but in some cases complete recovery took more than a year.
Vitamin B6 can also interfere with therapy for Parkinson's disease
and people who take as little as 200 milligrams a day may become
dependent on the vitamin, with deficiency symptoms resulting if it is
withdrawn too abruptly.
If Vitamin C in megadoses are abruptly
stopped, scurvy can result because the body has become dependent on
the high dose and large amounts of Vitamin C can interfere with lab
tests for blood glucose and make a person appear to be diabetic. It
can also interfere with uric acid and cholesterol tests. A megadose
of Vitamin C is defined as 1,500 milligrams a day for 10 weeks and
it could cause anemia.
Vitamins A, D, E and K are stored in the
body in fatty tissue and can accumulate to toxic levels if excessive
doses are taken on a regular basis. Vitamin A has resulted in a
number of vitamin poisoning cases.
Beta-carotene can give people an orange
or yellow skin color, but it can be confused with jaundice and has
been reported to cause loss of menstrual periods.
Vitamin D in megadose quantities can
cause toxic effects such as abdominal pain, loss of appetite, nausea,
vomiting, diarrhea, headache, excessive urination and thirst,
dangerously elevated calcium in the blood, calcium deposits in soft
tissues, bone pain, weakness, mental confusion, cataracts and kidney
failure and these symptoms can continue for a year or more after the
megadoses are stopped.
Vitamin E is recommended in megadoses for
everything from alleviating breast discomfort to warding off the
ravages of old age and preventing cancer. Side effects could cause
fatigue, nausea and blurred vision, but the most serious possibility
is the destruction of vitamin K and enhancement of the effects of
anticoagulant medications, which could result in hemorrhage. Patients
taking anticoagulants should not take vitamin E supplements.
Another problem with taking megadoses is
the accumulated ''inactive'' ingredients: fillers, flavors and
coloring agents. By Federal law, all vitamin and mineral
formulas that contain 50 percent or more of the United States
Recommended Daily Allowance for any nutrient must list all
ingredients on the package label. However, some manufacturers,
knowing that the Food and Drug Administration has more than it can
handle in dealing with safety issues, ignore the law.
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