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What Is It
Although it's the most abundant mineral in the body,
most adults get just half the calcium they need each day.
Eating enough calcium-rich foods may be difficult, but you
can prevent a deficiency by taking supplements. A wide array
of products line stores shelves. The most common forms are
calcium carbonate, calcium citrate, calcium citrate malate,
calcium gluconate, calcium phosphate, and calcium lactate.
A supplement's elemental (or pure) calcium depends on its
accompanying compound. Calcium carbonate (useful in antacids
to relieve heartburn) provides 40% elemental calcium, while
calcium gluconate supplies 9%. The lower the calcium content,
the more pills you need to meet recommended amounts.
What Does It Do
The majority of the body's calcium is stored in the bones
and teeth, where it provides strength and structure. The small
amount circulating in the bloodstream helps move nutrients
across cell membranes and plays a role in producing the hormones
and enzymes that regulate digestion and metabolism. Calcium
is also needed for normal communication among nerve cells,
for blood clotting, for wound healing, and for muscle contraction.
To have enough of this mineral available in the blood to perform
vital functions, the body will steal it from the bones. Over
time, too many calcium withdrawals leave bones porous and
fragile. Only a adequate daily calcium intake will maintain
healthy levels in the blood - and provide enough extra for
the bones to absorb as a reserve.
Common Uses
• Maintains bones and teeth.
• Helps prevent progressive bone loss and osteoporosis.
• Aids heart and muscle contraction, nerve impulses,
and blood clotting.
• May help lower blood pressure in people with hypertension.
• Eases heartburn.
Prevention
Getting enough calcium throughout life is a central factor
in preventing osteoporosis, the bone-thinning disease that
leads to a higher risk of hip and vertebrae fractures, spinal
deformities, and loss of height. The body is best equipped
to absorb calcium and build up bone mass before age 35, but
it's never too late to increase your intake of it. Several
studies show that even in people over age 65, taking calcium
supplements and eating calcium-rich foods help maintain bone
density and reduce the risk of fractures.
Additional Benefits
By limiting the irritating effects of bile acids in the colon,
calcium may reduce the incidence of colon cancer. Other research
indicates that diets that include plenty of calcium - as well
as fruits and vegetables - may actually help lower blood pressure
as much as some prescription medications do.
How Much You Need
The National Academy of Sciences, which sets the Recommended
Dietary Allowances (RDAs), has recently increased its recommendations
for daily calcium intake to 1,000 mg for men and women ages
19 to 50, and to 1,200 mg for those ages 50 to 70.
If You Get Too Little: A prolonged calcium
deficiency can lead to bone abnormalities, such as osteoporosis.
Muscle spasms can result from low levels of calcium in the
blood.
If You Get Too Much: A daily calcium intake
as high as 2,500 mg from a combination of food and supplements
appears to be safe. However, taking calcium supplements may
impair the body's absorption of the minerals zinc, iron and
magnesium. And very high doses of calcium from supplements
might lead to kidney stones. Calcium carbonate may cause gas
or constipation; if this is a problem, switch to calcium citrate.
How To Take It
Dosage: Be sure to get the recommended amount
of 1,000 to 1,200 mg of elemental calcium a day from foods,
supplements, or both. It’s often a good idea to also
add supplemental magnesium when taking calcium.
Guidelines For Use: To enhance absorption,
divide your supplement dose so that you don’t consume
more than 600 mg of calcium at any one time, and be sure to
take the supplements with food.
Other Sources
The most familiar and plentiful sources of calcium are dairy
products, such as milk, yogurt, or cheese. Choose low or nonfat
varieties: They're better for you and also contain slightly
more calcium, ounce for ounce. Orange juice fortified with
calcium malate, canned salmon and sardines (eaten with the
soft bones), collard greens, arugula, broccoli, and almonds
are good nondairy sources.
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