Calcium By Any Other Name is Still Calcium

The jackals selling unregulated dietary and herbal supplements have been hard at it bombarding the public with preposterous, unsubstantiated claims about the superiority of their particular miracle natural calcium products. Some disreputable companies have gone beyond just claiming a better calcium product and are now declaring that “coral calcium,” for example if it is from Okinawa, is the secret to good health and a long life.

The Health Research Group has been in existence since 1972, and we view this latest surge in calcium promotion as the “third wave” of natural calcium miracles. At one time, it was calcium from the Dolomite Mountains in the Italian Alps as nature’s perfect source of calcium and magnesium. Dolomite is the very common mineral, calcium magnesium carbonate. Some Internet Web sites still advertise it as “perfectly balanced nutritionally.”

Oyster shell calcium followed the dolomite craze as the next wave. Oyster shell calcium supplements contain calcium carbonate, the active ingredient in the antacid TUMS. One Web site maintains that it is used in traditional Chinese medicine to help with high blood pressure, heart palpitations, insomnia, dizziness, blurry vision, cold sweats and swollen lymph glands, among various other conditions.

The better choice for consumers, however, is chemically pure calcium products, rather than these so-called natural supplements.

One of the most important roles of calcium supplementation, and with the science to support it, is in osteoporosis. The rest of this article will focus on sources of calcium as applied to the prevention and treatment of postmenopausal osteoporosis.

The mainstays for decreasing the risk of postmenopausal osteoporosis are weight-bearing exercise, adequate calcium and vitamin D intake, and when indicated, drug treatment. Postmenopausal women require an average of 1,500 milligrams of elemental calcium per day (see the explanation below of elemental calcium). Therefore, supplementation may be helpful for women who do not receive an adequate dietary intake of calcium. The table at the end of this article lists the elemental calcium content of a number of foods. Vitamin D supplementation of 400-800 International Units (IU) per day may also be required to ensure adequate daily intake in postmenopausal women.

Calcium is an element; it cannot be produced synthetically, and it can combine with a number of other molecules to form what chemists call “salts.” Each of these other molecules weighs a different amount, while the weight of calcium stays the same. Thus, equal amounts of these salts, by weight, contain a different amount of calcium, actually elemental calcium.

Some of the most common calcium salts include calcium carbonate, calcium lactate and calcium gluconate. The table below lists the common calcium salts sold for calcium supplementation and the percentage of elemental calcium found in each.

For example, 1,000 milligrams, or 1 gram, of calcium carbonate would contain 400 milligrams (40% of 1,000) of elemental calcium while 1,000 milligrams of calcium gluconate would contain only 90 milligrams (9% of 1,000) of elemental calcium.

An issue that consistently comes up in the promotion of calcium supplements is the extent to which calcium is absorbed with the various products on the market, each company claiming that its calcium is better than the other.

In the late 1980s, it was found that some calcium supplements would not dissolve and passed straight through the bowel. The calcium salt must dissolve before the calcium can be absorbed into the body. The U.S. Pharmacopeia (USP), the organization that sets drug standards in this country, has since issued dissolution standards for calcium supplements.

The absorption of calcium is not complete and usually averages about 20 to 30 percent of intake. It requires an adequate intake of vitamin D in the diet and varies with age, decreasing after puberty. Taking calcium in doses of 500 milligrams or less with food increases absorption, particularly in patients with low levels of stomach acid (achlorhydria) and in those taking drugs such as the histamine-2 blockers cimetidine (TAGAMET) or ranitidine (ZANTAC) used for heartburn. Other drugs that lower stomach acid are the proton pump inhibitors such as omeprazole (PRILOSEC) or esomeprazole (NEXIUM), drugs also widely used for heartburn. Foods such as spinach, rhubarb, wheat bran and other forms of unrefined flour contain oxalic or phytic acids that can decrease the absorption of calcium.

Different calcium salts may vary somewhat in their absorption. However, there is little, if any, evidence that of the various calcium salts or calcium supplement products on the market, that one is more effective than another in reducing the risk of fracture due to osteoporosis.

Gastrointestinal adverse effects such as constipation, intestinal bloating and excess gas, particularly with calcium carbonate, are frequently seen with the use of calcium supplements. Those patients who form calcium-containing stones in their urinary tract are generally advised not to take calcium supplements. Calcium can interfere with absorption of some other minerals and drugs. Some natural calcium products may also contain lead, but the absorption of lead from such preparations is generally low. We can think of no reason why anyone should take the chance by using a natural calcium product.

The editors of the well-respected Medical Letter on Drugs and Therapeutics concluded in their April 2000 review of calcium supplements that:

Patients of both sexes and all ages need an adequate intake of calcium. There is little evidence that any calcium supplement is more effective than any other in preventing osteoporotic fractures. Calcium carbonate may cause more adverse gastrointestinal effects. Calcium citrate may be better absorbed. Taking any calcium supplement in doses of 500 mg or less with meals may improve absorption.

What You Can Do

You should avoid calcium-containing dietary supplements making claims that sound too good to be true. They probably are not true.

You should consider dietary sources of calcium as part of a plan to ensure adequate intake of calcium.

If you decide to use one of the many calcium salts that are available, check the label for the amount of elemental calcium. You should only purchase calcium salts that meet the USP standard for dissolution.

Some of the best sources of calcium are dietary. The table below appeared in the April 2000 issue of The Medical Letter on Drugs and Therapeutics and lists the elemental calcium content, in milligrams, of some common foods.