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Millions of Americans take calcium supplements daily
to prevent osteoporosis and attain the other health benefits
of adequate daily calcium intake. Concerns have occasionally
been raised in the media about the purity of calcium supplements,
specifically their lead content.
It is important to remember that lead is a naturally occurring mineral that
is found in the soil, water and the air. It is present in fruit, vegetables
and dairy products and is ubiquitous in the environment.
Although trace amounts of lead can be found in many calcium supplements,
the amount is very small. Supplements are made from refined calcium, and
in fact
contain
less lead than many dairy and vegetable food sources. Additionally, calcium
blocks absorption of lead by the body. Thus, ensuring adequate daily calcium
intake is also one of the best ways to reduce absorption of lead from other
dietary or environmental sources.
Federal Standards
for Lead Content
Standards for the purity of ingredients used in food products
have been established by the National Academy of Sciences' Food
Chemicals Codex and the U.S. Pharmacopoeia (USP). The concentration
of lead that is permissible in calcium carbonate, the most common
form of calcium used in supplements, is three parts per million
(3 ppm)(1). This can be illustrated by imagining a few grains
of sand in a sandbox.
A daily supplement of
1,000 mg of elemental calcium contains only about 0.25 mcg
of lead. That's 25 hundred-millionths of
a gram. This is minuscule compared to the Food and Drug Administration's
estimate of acceptable intake for the average person which is 750.0 mcg.
Calcium's Protective
Role
Calcium's role in preventing osteoporosis, providing potential benefits for
the cardiovascular system and maintaining overall health is well established.
As stated earlier, calcium also protects the body from lead absorption. Calcium
and lead are absorbed at the same site in the intestine, and this site prefers
calcium. Thus, the ingested lead passes though the gastrointestinal tract
and is excreted if there is also calcium present to prevent lead absorbtion. As more calcium is consumed, less lead is able to get into
the bloodstream.
Currently, most Americans are getting much less than the recommended daily
intake of calcium(2). A National Institutes of Health Consensus Panel has
recommended higher levels of daily calcium intake, from food if possible,
and alternatively
from supplements if not, for the entire population(3).
Take a Reliable
Supplement
To allay any
concerns about purity and quality, consumers should obtain
their calcium supplements, and their food products,
from reliable producers or manufacturers. Most calcium supplements from reputable
manufacturers are made with refined, high-quality "pharmaceutical grade" ingredients
with trace levels of lead far below the 3 ppm Federal standard.
Calcium carbonate is more concentrated than other calcium supplements,
so it contains the most elemental calcium, what the body uses,
and is less expensive than other sources of calcium in supplements.
References:
- Food Chemicals Codex, Fourth Edition, National Academy of Science,
National Academy Press, 1996.
- Third National Health and Nutrition Examination Survey (NHANES III),
National Center for Health Statistics, 1988-199 1.
- "Optimal Calcium Intake," NIH Consensus Development Panel
on Optimal Calcium Intake, Journal of the American Medical Association,
272:1942-1948, 1994.
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