COMPLETE
GUIDE OF MEDICAL COLLEGE & HOSPITAL
Berhampur
University
M
K C G Medical College, Berhampur
Utkal
University
S
C B Medical College, Cuttack
Sambalpur
University
V
S S Medical College, Burla, Sambalpur
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Cash
Safety:
ENOUGH VS.
TOO MUCH
Health
professionals are united in
their opinion that people are not consuming enough calcium. The latest
government health and nutrition study (NHANES III) documents that the
great majority of people, especially women, are not consuming the
Recommended Daily Allowance of calcium. Various health experts,
including a National Institutes of Health panel, have even recommended
consumption above the recently revised Recommended Daily Intake levels
to optimize bone health and increase other potential health benefits.
With the growing medical
consensus that individual need to increase their dietary intake of
calcium or, if that is not enough, take supplemental calcium, the
question arises: how much is too much?
Calcium:
Extremely Safe
It is very hard
to consume too much calcium. Most of the calcium absorbed by the body,
and not used by bone, is excreted in the urine. The Handbook of
Nonprescription Drugs notes that daily consumption of as much as 20
grams of calcium carbonate, or 8 grams of elemental calcium, causes few
side effects in healthy people.1
Much lower levels of calcium, in the range generally consumed, should
cause few if any adverse experiences.
Calcium
has been tested extensively in women with osteoporosis, women at risk
for osteoporosis, and pregnant and nursing women. These studies, using
varying amounts of supplemental calcium, typically between 1,000 and
2,500 mg per day, provide meaningful evidence of what constitutes a safe
daily amount of calcium.
Calcium
supplementation is the mainstay of osteoporosis risk reduction and
treatment. Studies of calcium related to fractures in post-menopausal
osteoporotic women2
and studies on
the process of bone formation and loss in osteoporosis3
have found doses
of 1.5 to 2.5 grams per day of elemental calcium to be safe.
Calcium
supplementation is also increasingly being considered in the maintenance
of healthy blood pressure in pregnant women. Increased calcium intake is
already a standard recommendation for women who are pregnant or
lactating to support the additional calcium needs of mother and baby at
this time.
A meta-analysis
of 14 controlled trials of calcium was recently published in the Journal
of the American Medical Association. Supplemental calcium between 1,000
and 2,000 mg per day was found to be safe in pregnant women.4
In a
recently completed trial, over 4,000 women were given 2 grams (2,000 mg)
per day of elemental calcium . No significant adverse events or
hypercalcemia (high calcium in the blood) were reported.5
Calcium:
Enough vs. Too Much
Supplemental
calcium up to 2,000 mg per day appears to be safe and effective in
helping to prevent osteoporosis and may reduce the risk for
pregnancy-induced high blood pressure. At present there is little
evidence that higher doses provide any further health benefit in most
healthy individuals, although selected individuals may require up to
2,500 mg.
Calcium,
like all minerals and vitamins, if consumed in great excess, can
potentially produce adverse effects. A single incidence, or several days
of excessive consumption, is unlikely to cause any harm. However, such
patients should be monitored for signs of abuse.
For
example, studies have examined patients with hypocalcaemia, or excess
calcium in the blood, and milk-alkali syndrome, a potentially dangerous
and rare complication of hypocalcaemia. Antacid abuse in the range of 4
grams (4,000 mg) to 60 grams (60,000 mg) of elemental calcium daily for
a prolonged period of time, usually combined with milk and for months or
years, has been reported in patients with milk-alkali syndrome.
Calcium
Safety: Expert Consensus
The 1994 NIH
Consensus Development Conference on Optimal Calcium Intake examined most
of the published literature on dietary calcium and supplementation, and
heard from experts on the effects of calcium on osteoporosis, heart
disease, pregnancy and cancer.
In their
final report, the panel stated that most current evidence points to
doses up to 1,500 mg per day as being helpful in preventing and treating
osteoporosis. The panel’s report concluded that 2 grams, or 2,000 mg,
of elemental calcium per day consumed regularly was safe for most
people.7
Most recently, a report from the National Academy of Science’s
Institute of Medicine evaluating the RDAs for various nutrients sets a
"Tolerable Upper Intake Level" for calcium at 2,500 mg per
day, which is an amount unlikely to pose risks of adverse health effects
in most healthy individuals.8
Individuals
seeking to supplement their calcium intake should follow accepted
therapeutic guidelines. If interested in more information about what’s
right for them, they should consult a physician.
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