In this article: Calcium: is it possible to get too much? Recipe: Portobello Mushrooms Stuffed with Greens and Cheese Recipe: Total calcium cookies Sources for this article

Calcium: News on the nutrient of the moment

This week's recipe: Portobello Mushrooms Stuffed with Greens and Cheese

We're starved for calcium. "It's alarming," says calcium expert Connie Weaver, Ph.D., of Purdue University.

Only 5% to 10% of females ages 9 to 50 meet dietary calcium quotas and less than 1% after 50, according to government surveys. Males, too, are deficient: Between ages 14 and 70, only 25% to 50% eat the recommended amounts. The figure drops to 10% after age 70. The truth is, most adult Americans get about 600 milligrams of this vital nutrient per day -- around half what experts recommend.

Worse, calcium intake is dropping dramatically among girls, who most need calcium for bone growth, says Tufts University bone researcher Bess Dawson-Hughes, Ph.D.

What does calcium do?

Saves bones. The major argument for getting more calcium is to prevent osteoporosis -- a weakening of bones that could cause fractures in later life. It's best to get calcium when you are young, creating strong bones. But it's never too late. Taking calcium supplements, along with vitamin D, reduced hip fractures in elderly French women by 43%. Their daily dose: 1,200mg calcium and 800 IU vitamin D. In a Tufts study, taking 500mg calcium and 700 IU vitamin D reduced total bone loss and cut hip, shoulder and other nonvertebral fractures 42% in the elderly. Vitamin D enhances calcium absorption.

Relieves PMS. Premenstrual syndrome may be partly a calcium deficiency. Women with moderate-to-severe PMS who took 600mg calcium carbonate twice a day had a 48% reduction in overall PMS symptoms, including mood swings, depression, anxiety, anger, water retention, cravings, cramps and headaches, found Susan Thys-Jacobs, an endocrinologist at Columbia University.

Helps prevent colon cancer. Research in animals and humans suggests that calcium blocks processes involved in colon cancer and that high-calcium diets help curb colon cancer. The latest, from Seattle's Fred Hutchinson Cancer Research Center: Colon cancer risk dropped 40% in men and women who ate the highest calcium diets compared with those who ate the lowest. But Harvard researchers warn that calcium supplements and dairy products may promote prostate cancer. In one study, taking more than 2,000mg calcium a day boosted risk of metastatic prostate cancer fourfold.

Fights fat. A low-calcium diet may pile on body fat, according to fascinating new evidence. University of Tennessee researchers first discovered this in mice. New human research supports it. Purdue researchers note that women who ate an average number of calories tended to gain weight on a diet with 600mg calcium a day but to lose weight on a diet of 1,200mg calcium daily. The theory is that a lack of calcium causes a specific gene to suppress fat breakdown and encourage fat storage.

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Can you get too much?

Yes, the National Academy of Sciences puts the "tolerable upper intake level" for calcium at 2,500mg a day. With an overdose, you may have fatigue, dizziness, kidney problems, constipation and poor absorption of nutrients such as zinc. Calcium-fortified foods have extremely high amounts and could put you over the top. "Make sure you're not going above 2,500mg, including diet and supplements," advises Weaver. She finds 1,500mg a day adequate for almost everyone.

To get the most from your supplement

Always take calcium pills with food. Stomach acid secreted during eating helps break down calcium, notably common calcium carbonate. This is critical for 20% to 40% of older people who make little stomach acid.

Don't take all your calcium at once. The higher the dose, the less is absorbed. Take half your calcium in the morning with breakfast and half with dinner. Your body efficiently absorbs no more than 500mg at a time, says Weaver.

Cost doesn't matter. Less expensive calcium carbonate, such as Tums, is absorbed just as well as pricey calcium citrate -- if you take it with food, says leading researcher Robert Heaney, M.D., Creighton University.

Don't get it only from pills. Typically, an adult gets 500-700mg in food, so consider a supplement of another 500-700mg as "insurance." Getting as much as 1,200-1,500mg in pills alone is needless, except on a doctor's advice.

Get enough vitamin D. You may need a supplement to enhance calcium absorption, especially if you aren't exposed to sunlight, which triggers vitamin D production in your body. And 400-800 IU is considered safe and adequate.

Did you know?

Eating lots of calcium in food can help deter kidney stones. But excessive calcium in supplements may promote kidney stone formation in some people, says Weaver.

If you are on a high-protein Atkins or Zone diet, you need 1,500-2,000mg calcium daily, because protein washes calcium out of the body, says Heaney.

High salt intake blocks calcium absorption. Older women who eat the most sodium lose the most bone, says Dawson-Hughes. It takes an extra 125mg of calcium to offset 120mg sodium, she finds.

You absorb 25% less of the calcium in soy milk than in cow's milk. To match milk, a soy beverage must contain 500mg a serving.

Calcium doesn't build strong bones unless you also do weight-bearing exercise, finds research at South Dakota State University.

You need calcium to maximize the benefits of estrogen or osteoporosis drugs, such as Fosamax. Estrogen's bone benefits tripled in women who took in 1,200mg of calcium daily instead of 600mg, finds Columbia University research.

Men have 20% of bone fractures among older Americans.

Portobello Mushrooms Stuffed With Greens and Cheese

1 10-ounce package frozen collard greens or kale (about 21/2 cups cooked)
2 1/2 Tbs. extra virgin olive oil
1 1/2 Tbs. fresh lemon juice
2 large garlic cloves, crushed
1 1/2 tsps. dried thyme
4 portobello mushrooms, stems removed
4 ounces Brie cheese, rind removed
Salt and black pepper to taste

Preheat oven to 350. Microwave greens using package directions; drain and squeeze dry. Combine greens, oil, lemon juice, garlic, thyme. Put mushrooms, stem side up, in a baking dish. Fill hollows with greens. Top with cheese and freshly ground black pepper. Bake 10 minutes. Broil to brown cheese, 2 minutes.

Serves 4. Per serving: 228 calories, 12g carbohydrates, 17.1g fat (1.3g saturated), 11g protein, 3g fiber, 220mg sodium, 218mg calcium.

Total Calcium Cookies

4 cups Total cereal
3/4 cup quick cooking oats
1 packed cup brown sugar
2 tsps. ground cinnamon
1 tsp. ground ginger
1 tsp. baking soda
2 beaten eggs or 1/4 cup egg substitute
1 jar (2 1/2 ounces) canned baby prunes
1 cup chopped walnuts

Preheat oven to 350 degrees. Crush Total cereal in a blender until it looks like coarse flour. Add oats, spices, baking powder and stir. In another bowl combine eggs, sugar, nuts. Add dry ingredients to wet ingredients and combine thoroughly. Spray a cookie sheet with canola or olive oil. Drop cookies by the teaspoon on the sheet about an inch apart. Bake 12 to 15 minutes in a 350 degree oven.

Makes about 40 high-calcium cookies. Each cup of Total has 1000mg calcium. Per cookie: tk

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Sources for this article

Calcium saves bones
Chapuy M.C., N Eng J Med 1992 Dec 3; 327(23):1637-42
Dawson-Hughes B., N Eng J Med 1997 Sep 4;337(10): 670- 6

Calcium relieves PMS
Amer J Obstet Gynecol. 179:444,1998

Calcium helps prevent colon cancer
Kampman E., Cancer Causes Control 2000 May; 11(5): 459-66

Calcium fights fat
Unpublished data from Michael B. Zemel, director Nutrition Institute, University of Tennessee in Knoxville and Connie Weaver, Purdue University

Calcium maximizes estrogen or osteoporosis drugs
Jeri W. Nieves, Ph.D., Columbia and John Bilezikian, M.D., Columbia University

Noted health journalist Jean Carper is the author of Your Miracle Brain (HarperCollins, $26).