By Dr. Daniel J. Crisafi
Selecting a Calcium Supplement
In order to properly select a calcium supplement, it is important to review some rudimentary facts.
Calcium is arguably the most extensively used supplement in North America, with the exception of vitamin C. Despite this, the average consumer is given very little information about how to select a calcium supplement. In order to properly select a calcium supplement, it is important to review some rudimentary facts. In this article I offer a few pointers that will help the next time you’re in the calcium aisle.
In foods and supplements calcium is not found in its pure or elemental form, rather it is bound with other elements, forming a more complex molecule. For example, oyster shell or calcium carbonate is just 40 percent calcium. Our bodies use only the elemental or “pure” calcium. Fortunately, in Canada mineral supplement labels must help us determine the exact amount of elemental or useable calcium we are getting. This can be done in a variety of ways. In all cases, it is the side panel or back panel of the label, (the ingredient section) that gives us the information we need.
Once we know the amount of elemental calcium available in a formula, the next question is how effectively will it get absorbed? In other words, “will the calcium actually end up in my blood where it can be transported to nerve cells and bones or, will it end up in my stool?”
The question is essential because not all calcium is absorbed equally. In one analysis, the absorption potential of different calcium supplements was evaluated. In a liquid solution, 330 mg of calcium supplied an estimated 330 mg of calcium to the blood. On the other hand, 500 mg of calcium carbonate in a tablet form supplied an estimated 50 mg of calcium to the blood. That’s 100 percent absorption potential versus 10 percent!
Today, the calcium products available in health food stores are generally made from complexes of ionized calcium that are highly soluble. These include amino acid chelate, calcium citrate, calcium lactate, calcium gluconate, calcium citrate/malate. Other calcium forms are not as soluble. These include calcium carbonate, calcium phosphate and dolomite.
Because of its reduced solubility and because it requires sufficient levels of hydrochloric acid to be dissolved, calcium carbonate (the most popular conventional form of calcium) can only be absorbed at a level of about five percent in women over 40, the very individuals who require it most in order to prevent osteoporosis.
Stomach acids also have a role to play in maintaining the relative solubility of calcium. However, as some researchers have pointed out, insufficient hydrochloric acid may actually affect a large percentage of the population, specifically those most at risk of osteoporosis. As a matter of fact, calcium citrate was shown to be absorbed significantly more efficiently than calcium carbonate in cases of low hydrochloric acid, and furthermore it has demonstrated the ability to stop the progression of bone loss.
Calcium is available in a variety of forms. The most common forms are solids (tablets, capsules and chewable tablets), suspensions (most liquid calcium products) and solutions. In solutions, calcium is completely dissolved in a liquid (water), therefore it is absorbed more rapidly and more completely than suspensions, solids or regular liquids.
Several nutrients are involved in the body’s ability to use calcium effectively. These nutrients are very important since it’s not just the amount of calcium that is absorbed that counts, it’s also the amount of calcium used by the body. Primary among these important nutrients are magnesium and vitamin D.
Magnesium is required to convert vitamin D into its active form, the form that is required to help absorb calcium. This mineral is also important to the activity of the parathyroid, the major gland involved in calcium metabolism. Magnesium is also required to convert calcium into hydroxyapatite, the form of calcium found on the bones.
Finally, it is firmly established that vitamin D is required for the absorption of calcium. This is due in part to vitamin D’s regulating role with the protein involved in calcium absorption.
The health food industry pioneered calcium supplementation for the general public decades ago. At that time they recommended calcium carbonate (oyster shell) and dolomite. These were the best calcium sources available in supplement form at the time. The second generation of calcium supplementation involved using a protein to chelate the calcium, making it more absorbable. The next generation of calcium supplements involved calcium salts, especially calcium citrate. These calcium supplements, especially calcium citrate, improved absorption, especially in individuals with hypochlorhydria.
The new generation of calcium supplements meet the consumer’s increasing need for a highly absorbable form of calcium. They supply calcium and magnesium citrate blends that are liquid and in solution, complemented with vitamin D. These ensure the best possible absorbability in the most digestive tract friendly format for children, adults and the elderly.
Dr. Daniel J. Crisafi
Dr. Daniel Crisafi was born in Montreal and has earned a bachelor’s and master’s in science, as well as a Ph.D. (doctorate) in nutrition. He has also acquired a doctorate in naturopathy and a master herbalist’s degree. Daniel was editor-in-chief of Vitality Québec and Health and Vitality magazines. The author of five books, including Candida Albicans and the Probiotic Approach, Dr. Crisafi has taught and/or lectured at McGill University, Université du Québec à Montreal, Florida Atlantic University, University of Toronto, and l’Université de Paris (Bobigny). He has been a member of the academic advisory board of the Université des Sciences de l’Homme de Paris, Vice-Chair of the board of directors of the Canadian Health Food Association, a member of the advisory board of the Canadian Council of Continuing Education for Pharmacists, and a guest on various TV and radio shows, including Canada AM.
