Calcium

Calcium

A Crucial Bone Builder, and More

Many women defy aging by spending time and energy shaping their bodies--reducing a curve here, building a muscle there. But what about the bones beneath those muscles and curves? Your bones give you stature and support. They are living organs full of blood vessels, constantly manufacturing new cells to give strength to your frame.

If you want an upright, sturdy frame for years to come, it's important to understand that your bones need nourishment. The nutrient that gives youth and strength to your bones, and, more importantly, wards off the bone-thinning effects of osteoporosis, is calcium. And if your bones could speak, they'd probably ask for more.

If you're like most women, you already know that the easiest way to get your calcium is by drinking milk and eating other dairy products. But, if you're like most women, you're not getting enough. You may drink milk only as a dollop in your coffee. Or perhaps you're swearing off dairy products like cheese because you're watching your fat intake.

If you're counting on calcium from vegetables, you may be getting less than you think. The calcium in dark leafy vegetables such as spinach and kale may not always find its way to your bones, says Clifford Rosen, M.D., director of the Maine Center for Osteoporosis Research and Education in Bangor. "Because people absorb calcium from vegetables in variable ways, you won't know whether you are absorbing it efficiently, even though you may be taking in generous amounts," he says.

Sometimes the stresses of busy lives and a culture that pressures women to be thin encourage us to eat sporadically or diet repeatedly over the years. That kind of on-the-run nutrition can leave you seriously deficient in calcium.

You Can't Do without It

Calcium is a mineral you need to survive. When your body calls on its daily dose of calcium and can't find it in food, it plucks it from your bones. As you get older, this feeding off bone eventually causes your bones to become porous and brittle. Unfortunately, your bones may not let you know it until it's too late--when you fall and break one. This bone loss is called osteoporosis, and it's especially cruel to older women.

The female hormone estrogen to a great degree helps protect your bones from calcium theft. But once menopause hits and estrogen wanes, your bones are left vulnerable. Couple this loss with low calcium intake, and bone depletion accelerates.

Calcium can also help lower your cholesterol. In one study, researchers found that when people with cholesterol levels in the high range of 240 to 260 took in an extra 1,800 milligrams of calcium a day, they reduced their total cholesterol by 6 percent, reports the study's conductor, Margo Denke, M.D., assistant professor of medicine at the Center for Human Nutrition at the University of Texas Southwestern Medical Center at Dallas and a member of the nutrition committee of the American Heart Association. Even better, LDL (low-density lipoprotein) cholesterol--the bad cholesterol that causes all the damage to coronary arteries--dropped by 11 percent. Although the study was conducted on men, Dr. Denke feels the result would be similar for women.

Getting Our Share

Because calcium is so important, our need for it changes throughout life. A child with growing bones has a recommended dietary allowance (RDA) of 1,200 milligrams. After the age of 24, when bone growth has stopped, the RDA is only 800 milligrams.

But many doctors believe that women should be getting much more. Many researchers say 1,000 to 1,500 milligrams daily is the safe and optimum level for bone protection. And some, including Dr. Denke, say that 2,000 milligrams a day is needed to achieve a cholesterol-lowering effect.

Studies show that 85 percent of all women don't get even the RDA for calcium. It's estimated that the average calcium intake for American women between the ages of 35 and 50 is 530 milligrams a day. Here's what you can do to boost that number.

Don't go a day without dairy. How important is dairy? "Calcium is most available to your body when it comes from milk and milk products," says Richard J. Wood, Ph.D., chief of the Mineral Bioavailability Laboratory at the U.S. Department of Agriculture Human Nutrition Research Center on Aging at Tufts University in Boston.

To avoid the fat and calories, only reach for low-fat options. Your favorite supermarket offers low-fat versions of the full array of dairy products: milk, cheeses, sour cream, cream cheese and yogurt, just to name a few. And don't turn up your nose until you've tried it.

Dairy products also give you the most calcium per spoonful. An eight-ounce cup of plain low-fat yogurt offers 414 milligrams. Skim milk boasts 351 milligrams per eight-ounce serving. A half-cup of part-skim ricotta cheese, which you might find in a healthy portion of lasagna, has 337 milligrams.

Add nondairy sources. If you have difficulty digesting dairy products or simply do not enjoy them, broccoli is a good choice as a calcium source. Just 31/2 ounces of cooked broccoli will give you 205 milligrams of calcium--much more than other vegetables.

Also try tofu, a mild, versatile soy product you'll find in the produce section of your grocery store. It's loaded with calcium. But some tofu brands have more calcium than others, depending on the ingredient used to form the curds. A half-cup of tofu made with nigari (magnesium chloride) contains 258 milligrams of calcium. But the same amount of tofu made with calcium sulfate contains a full 860 milligrams of calcium. Check the curding agent on the label.

Don't forget the fish. Since calcium makes its home in your bones, it only makes sense that bony fish are a good source of calcium. Canned pink salmon with bones contains 181 milligrams of calcium per three-ounce serving, and two sardines (about 1 ounce total) contain 92 milligrams.

Fortify with vitamin D. "No matter how much calcium you include in your diet, your bones won't retrieve it without the help of vitamin D," says Michael F. Holick, M.D., Ph.D., director the Vitamin D, Skin and Bone Research Laboratory at Boston University Medical Center. Fortunately, for most women, getting enough vitamin D isn't a problem. Casual, everyday exposure to sunlight--just 15 minutes will do--will meet your body's daily requirements for vitamin D, says Dr. Holick. How? Sunlight triggers the production of vitamin D in your skin, he says.

Also, vitamin D comes in an array of fortified foods we eat every day, like milk, cereals and breads. Doctors advise against taking vitamin D supplements, however, because too much can be toxic.

Dump the Popeye diet. Spinach contains plenty of calcium but it also contains compounds called oxalates, which bind with the mineral and render much of it unavailable to your body. Although you should enjoy spinach for the other good nutrients it has to offer, don't overdo it, says Paul R. Thomas, Ed.D., R.D., staff scientist with the Food and Nutrition Board of the National Academy of Sciences in Washington, D.C. "Eating spinach salad four to five times a week is fine; just don't depend on it as your major source of calcium," he says.

Supplement Your Diet

Most doctors will tell you that a well-rounded diet consisting of lean meats and fish and plenty of fruits, whole grains, vegetables and low-fat dairy products will provide you with all the vitamins and minerals you need to maintain good health. But they may also tell you that eating a well-rounded diet is no guarantee that you're getting all the calcium you need, especially if you're a woman over 30. So your best protection may be calcium supplements.

"If you prefer to get your calcium from supplements, choose those made with calcium citrate," says Dr. Denke. All forms of calcium can sometimes interfere with iron absorption or cause kidney stones. Calcium citrate is the supplement that is least likely to promote kidney stone formation.

If you do choose calcium carbonate, it's best to take it with meals, says Dr. Rosen. The acid your body produces when you eat will break down the calcium carbonate and allow it to be absorbed.

Calcium carbonate is found in antacid tablets, and many women opt to chew them as a source of calcium. But you need to be cautious. Some antacid brands, such as Gelusil, Maalox and Mylanta, are not recommended as calcium sources because they also contain aluminum, which can prevent adequate mineralization in bone. Your best bets, says Dr. Rosen, are Tums and Rolaids--both aluminum-free.

How much should you take? "If you drink three eight-ounce glasses of milk a day, then one 500-milligram calcium supplement would be plenty," says Dr. Rosen. "If you can get to 1,500 milligrams either through diet or a combination of diet and supplements, then you're okay."