Calcium - Benefits Of Calcium 11/11
What are the Benefits of Calcium?
The surprising benefits of calcium: you know you need it for strong bones, but calcium protects your health in other important ways, too. Here's what this
amazing mineral can do for you.
YOU'VE HEARD IT A MILLION TIMES: You need calcium to prevent osteoporosis.
But a lack of this mineral means more than weak bones, says Robert P. Heaney,
M.D., a calcium researcher and member of the Osteoporosis Research Center at
Creighton University in Omaha, Neb. Key organs and bodily functions, like your
heart and metabolism, need calcium to operate at their best. Yet only 21 percent
of us are getting the recommended amount of calcium, according to federal
Here are five important but little-known ways that getting more calcium can
improve your health. For specifics on how much you need to achieve these
benefits, see "How Much Calcium Do I Need?" page 55.
Calcium helps keep the weight off.
Research suggests that if you don't get enough calcium in your diet, you're
likely to be overweight, Heaney says. Of course, it's possible to be overweight
even if you do get plenty of calcium, but Heaney points out that an adequate
supply appears to make it easier to maintain a healthy weight.
The reason has to do with your body's response to a calcium deficit. When you're
low, your body thinks you're starving and enters emergency mode, releasing
parathyroid hormone from four glands in your neck. This hormone stimulates your
bones to release some calcium into your bloodstream. Your kidneys also deliver a
dose of a hormone called calcitriol, a form of vitamin D, to increase your
ability to absorb calcium.
The trouble is that parathyroid hormone and calcitriol also stimulate the
production of fat and inhibit its breakdown. As a result, your body stores fat
and holds on to it stubbornly, even if you're on a low-calorie diet, explains
Michael B. Zemel, Ph.D., head of the department of nutrition at the University
of Tennessee at Knoxville. On the other hand, a high calcium intake suppresses
these hormones so your body stores less fat and also breaks it down easily, he
In his research, Zemel found that calcium from low-fat or nonfat dairy products
was more effective for weight loss than any other form.
Calcium protects your heart.
If you're low on calcium, researchers say, you're more likely to have high blood
pressure. Your body releases the hormone calcitriol in response to a calcium
shortage, and calcitriol acts on the smooth muscle walls of your arteries,
constricting them and elevating your blood pressure, says Heaney.
In fact, your calcium intake may be almost as important to blood pressure as
your sodium intake, says Gene Spiller, Ph.D., the director of the Health
Research and Studies Center in Los Altos, Calif., and co-author of Calcium:
Nature's Versatile Mineral (Avery, 2000). He explains that an adequate supply of
calcium helps muscles--including your heart muscle--do their work of contracting
and relaxing. Calcium also appears to help your nervous system regulate the
level of pressure in your arteries.
The benefits of calcium on heart health were confirmed in the Dietary Approaches
to Stop Hypertension (DASH) study, published in the New England Journal of
Medicine in 1997. The study found that a healthy diet that included two to three
servings a day of low-fat, calcium-rich dairy foods like yogurt reduced systolic
blood pressure by 5.5 points more than the control diet, and reduced diastolic
blood pressure by 3 points more. "We don't want to oversell the importance of
calcium [for heart health], because it's only a part of the puzzle," says
Heaney. "But it's a very useful part."
Calcium improves premenstrual moods.
A 1998 study led by Susan Thys-Jacobs, M.D., of St. Luke's Roosevelt Hospital in
New York City, found that getting enough calcium can ease the symptoms of
premenstrual syndrome (PMS). In this study of 497 women, published in the
American Journal of Obstetrics and Gynecology, half took 600 mg supplements of
calcium carbonate twice a day, while half took a placebo. The women who took
calcium experienced significantly fewer symptoms in two months and improved even
more after three months.
The explanation comes down (again) to calcium-regulating hormones. Your body
suppresses the hormones if your calcium supplies are adequate, but releases
these hormones if you're not getting enough. Women who suffer from PMS appear to
have elevated levels of these hormones during their menstrual cycle. Thys-Jacobs
explains that it's no accident that some of the symptoms of PMS, like cramping,
irritability, and depression, are similar to the symptoms of a calcium-deficient
The good news for PMS sufferers is that consuming calcium appears to ease most
of the symptoms. "We found that calcium is effective both on the emotional and
physical side," Thys-Jacobs says. "It has a major effect on irritability,
cravings, mood swings, breast tenderness, and other symptoms."
Calcium protects against colon cancer.
Adequate calcium intake may reduce your overall risk of colon cancer and
suppress the growth of polyps that can lead to cancer. Researchers don't know
exactly why this happens, but Heaney says it may be linked to the excess calcium
that's left in your intestines after your body absorbs what it needs. On its way
through the colon, this unabsorbed calcium is believed to bind with cancer
promoters so they're excreted together from the body. Studies have shown that
both food sources of calcium and calcium supplements provide this protective
Calcium maintains healthy teeth.
Calcium protects your teeth in an indirect way. Your teeth themselves are
relatively inert, meaning that the calcium they contain usually stays there.
Your jawbone is the potential problem. Like other bones, it gradually surrenders
calcium for needs elsewhere in your body if you're not consuming enough. As your
jaw weakens, your teeth loosen, creating gaps where bacteria can invade,
triggering infection, inflammation, and bleeding. In fact, the condition of your
teeth and gums can be a window to the overall health of your bones, says Bonnie
Bruce, R.D., D.P.H., M.P.H., a registered dietitian and a research director in
immunology and rheumatology at Stanford University in Stanford, Calif.
"The first signs of osteoporosis are sometimes found by a dentist, because
something is happening to the structure of the jawbone," Bruce says. Talk to
your health care practitioner if you experience the unexpected loss of a tooth
or your teeth start to feel loose. Sufficient calcium intake can prevent these
problems in the first place.
Which Foods Provide the Most Calcium?
AIM TO GET MOST OF YOUR CALCIUM FROM FOOD, SINCE
food provides other important nutrients, too. Some researchers, including
Robert P. Heaney, M.D., of the Osteoporosis Research Center at Creighton
University in Omaha, Neb., say low-fat or nonfat dairy products, including
yogurt and milk, are an ideal way to get your calcium because they're
inexpensive and easily absorbable.
Still, dairy consumption is controversial. Milk products
often contain antibiotics,
which may contribute to
the problem of antibiotic
resistance, and rBGH, a
growth hormone with an
uncertain safety record.
Some studies link high
intakes of dairy to cancer,
and lactose intolerance,
an inability to
digest milk sugar, is common.
If you choose to eat
dairy foods, consider organic products that are antibiotic-and
rBGH-free. No matter what your decision on dairy, get
to know the full range of calcium-rich foods.
FOOD CALCIUM CONTENT
Yogurt, plain, low-fat, 8 ounces 448 mg
Orange juice, calcium-fortified, 1 cup 350 mg
Sardines, canned with bones, 3 ounces 324 mg
Cow's milk, nonfat, 1 cup 300 mg
Soymilk, calcium-fortified, 1 cup 300 mg
Sesame seeds, 1 ounce 280 mg
Collard greens, cooked, 1 cup 226 mg
Tofu, prepared with calcium sulfate, 1/2 cup 204 mg
Blackstrap molasses, 1 tablespoon 172 mg
White beans, cooked, 1 cup 161 mg
Bok choy, cooked, 1 cup 158 mg
Parmesan cheese, grated, 2 tablespoons 138 mg
Figs, dried, 5 medium 135 mg
Navy beans, cooked, 1 cup 127 mg
Quinoa, cooked, 1 cup 100 mg
Broccoli, cooked, 1 cup 94 mg
How Much Calcium Do I Need?
Ages 9 to 18: 1,300 mg a day
Ages 19 to 50: 1,000 mg a day
Ages 51 and Older: 1,200 mg a day
RESEARCHERS RECOMMEND THAT YOU GET this amount from a combination of food
and supplements. Don't consume more than 2,500 mg a day in supplement form; this
may increase your risk of kidney stones. If you have hyperparathyroidism or a
history of kidney stones, talk to your doctor before taking calcium supplements.
Which Calcium Supplement Should I Take?
SUPPLEMENTS MADE OF CALCIUM CARBON ate are easy to find and inexpensive,
but they should always be taken with meals for best absorption.
Calcium citrate supplements can be bulkier and more expensive than other
supplements, but they are well-absorbed and can be taken at any time, with or
without meals, says Bess Dawson Hughes, M.D., professor of medicine and chief of
the Calcium and Bone Metabolism Lab at the U.S. Department of Agriculture Human
Nutrition Research Center on Aging at Tuffs University in Boston.
In this case, it may be better to choose synthetic supplements over naturally
derived ones. A 2000 study detected lead in some supplements made from oyster
shells, the mineral dolomite, and bone meal. Dawson-Hughes says the lead in
those supplements was far below dangerous levels. "Having said that, the less
consumed, the better," she says.
Can Calcium Increase a Man's Risk of Prostate Cancer?
A 2001 STUDY OF MORE THAN 20,000 MEN CONDUCTED at Harvard Medical School in
Boston found that those who consumed the most calcium and dairy products had a
30 percent greater risk of prostate cancer than those who consumed the least.
These results don't mean men should eliminate dairy and calcium supplements from
their diets. Harvard researcher Edward Giovannucci, M.D., D.Sc., believes the
recommended daily intake of 1,000 mg "is reasonable for now until we know more
about prostate cancer. However, it may be prudent not to exceed this level
How Can I Boost My Calcium Absorption?
* DO GET ENOUGH VITAMIN D. This vitamin helps transport calcium across your gut
to the rest of your body. If you live in a sunny region, you can get vitamin D
by spending 15 to 20 minutes in sunlight two or three times a week. If you live
elsewhere, make an effort to eat vitamin D-fortified foods like cereal and
* DON'T CONSUME MORE THAN 500 MG OF CALCIUM AT A TIME. Your body can only absorb
so much of this mineral at once.
* DO TAKE ONE DOSE AT NIGHT. Your bones lose some calcium while you sleep; a
nighttime dose may minimize the loss.
* DON'T SMOKE CIGARETTES, AND DON'T OVERDO SODIUM OR CAFFEINE. All three are
thought to reduce calcium absorption.
Christopher Ott is a writer in Madison, Wis. He suspects that he hasn't been
getting enough calcium.