It’s about time we woke up to the importance of this mineral. Huge segments of the population still receive far less than the amount needed to maintain strong bones and teeth and to help prevent osteoporosis. Only 10 percent of women 50 and younger consume the recommended 1,000 milligrams of calcium each day. And less than a third of U.S. teens consume the 1,300mg they need each day to support normal bone growth. (The body forms nearly half its bone during the teen years.) The irony is that now, with the onslaught of fortified foods, folks who are determined not to miss out on calcium may be getting too much of a good thing. Most people can handle supplementation, says Dr. Ian Thompson of the University of Texas Health Science Center at San Antonio. “But if you do it to great excess, the body may not necessarily be able to adjust.” Here is some guidance on how to determine your own calcium needs, and how to steer clear of both deficiency and excess.
The fifth most-abundant element on earth often seems like a miracle mineral, and in some ways it is. Besides maintaining our skeletons, it may help ward off everything from premenstrual syndrome to hypertension, colon cancer and breast cancer. Food remains the best source of calcium, since it provides other nutrients as well. In a cup of nonfortified milk, for example, you get protein, riboflavin and vitamin D along with about 300mg of calcium. Unfortunately, Americans have cut back dramatically on calcium-rich foods in recent decades. Aggressive marketing has helped push soft-drink consumption to record levels, while milk consumption has fallen off. A typical teen now drinks twice as much soda as milk.
The new supplements and fortified foods can help fill that gap. They help people get adequate calcium without having to overhaul their diets, says Stephanie Atkinson, chair of the National Academy of Sciences calcium committee. Fortified Coco Pops may hold more appeal than plain yogurt, but getting the most out of supplemental calcium takes some effort. First, you need to know which type you’re taking. The most common form of the mineral, calcium carbonate, is derived from limestone and oyster shells. This form, which is used in Tums and most tablets, works best when taken in doses of 500mg or less and combined with food and vitamin D. Calcium citrate malate (the stuff used in many fortified juices) doesn’t require food or vitamin D and is slightly better absorbed. Whatever the form, calcium taken with a lot of sodium, protein or caffeine is more likely to be excreted. For every 500mg of sodium you eat, you lose 10mg of calcium. And each gram of dietary protein costs the body 1mg to 1.5mg of calcium. A body builder who downed 130 grams of protein each day could lose nearly 50mg of calcium in the process.
It’s hard to get too much calcium from food sources, but supplements and designer foods can easily push people beyond what’s needed or even safe. At doses of 2,500mg or more, calcium poses several potential hazards. Besides causing constipation and stomach upset, it may block the absorption of other critical minerals, especially zinc and iron. Extreme doses can also harden the kidneys and contribute to the formation of kidney stones. And preliminary research suggests that men with high calcium intake are slightly more vulnerable to prostate cancer.
Could the foods and supplements we’re taking really push us into the danger zone? You bet. In fact, you could approach the maximum safe level of 2,500mg a day just by eating a heavily fortified breakfast (chart). Start with a glass of Tropicana Premium Plus OJ with calcium. Pour some calcium-fortified Lactaid milk on your General Mills Basic 4 cereal. Then enjoy a cup of plain nonfat yogurt and a fortified English muffin with a pat of fortified butter. And top it all off with a Centrum Complete multi-vitamin and a Viactiv caramel chew. By the time you leave the table, you’ve had 2,400mg of calcium, and you still have a whole day of eating ahead of you. Again, there is no need to avoid all these foods. Just read the labels and keep track of what you’re eating in the course of a day. Calcium may be a miracle mineral–but even miracles are best in moderation.
