Osteoporosis is a disease in which the bone gradually loses its density and thins. Bone loss occurs when the body does not produce enough new bone tissue or when too much existing bone is reabsorbed. Patients with osteoporosis are more prone to hip, wrist, or vertebral fractures. According to 2011 information from the National Institutes of Health, osteoporosis affects more than 10 million U.S. adults, 80 percent of whom are women.
The Role of Calcium in Maintaining Bone Density
Osteoporosis is a treatable and preventable disease. The goal of osteoporosis therapy is to achieve a net increase in bone tissue. The body needs the mineral calcium to produce new bone. Almost all the calcium in the body is stored in the form of bone or teeth. When the body needs more calcium for other purposes, it takes it from the bones. As calcium leaves the bones and enters the bloodstream, the bones are left thinner, weaker and less dense.
Preventing Bone Loss by Calcium Supplementation
You can slow or prevent the loss of calcium from bone tissue by eating more calcium-rich foods or by taking calcium supplements. You should take in at least 1200 mg of calcium a day. Calcium-rich foods include cheese, ice cream, leafy green vegetables, milk, salmon, sardines with the bones, tofu and yogurt. If you are not able to take in enough calcium through your diet, consider calcium supplements. Calcium supplements vary widely in price, strength and absorbability. Most over-the-counter calcium supplements contain calcium carbonate, calcium citrate, calcium lactate or calcium phosphate. These differ in their abilities to dissolve in the stomach and release calcium into the blood. If the compound does not dissolve, the calcium cannot reach the bloodstream and if the calcium cannot reach the bloodstream, the supplement is useless.
Most Common Calcium Compounds
Calcium carbonate is 40 percent calcium; a tablet containing 500 mg of calcium carbonate provides 200 mg of calcium. Calcium carbonate is best absorbed when taken with food. Some drugs used to treat indigestion or acid reflux will reduce the amounts of acid in the stomach. Calcium carbonate releases calcium into the blood best in an acidic environment. Calcium carbonate supplements are sometime made from oyster shells or bones, which may contain small amounts of lead. Another popular calcium compound is calcium citrate. By weight, calcium citrate contains 21 percent calcium. It dissolves quickly in the stomach and rapidly enters the bloodstream. Calcium citrate supplements require a larger dose than calcium carbonate. Calcium lactate is a calcium compound that contains 37 percent calcium. It is well absorbed with or without food and regardless of the stomach acid amounts. Calcium lactate, as well the compounds, calcium phosphate and calcium gluconate are all less dense than calcium carbonate. A tablet or capsule of any of these compounds weighs far less than an equal sized calcium carbonate capsule or tablet.
Conclusion
For patients who are not being treated with acid blockers for indigestion or acid reflux, the United States Pharmacopoeia (USP) approved calcium carbonate is the preferred choice of calcium supplements. The UPS seal is an assurance of the strength and purity. USP standards also limit the amount of lead allowed in calcium carbonate supplements. Calcium carbonate is the least expensive calcium supplement. It is well absorbed and tolerated by most people. It is available in tablet capsule, caplet, liquid and capsule dosage forms. It is also available in flavored, chewable dosage forms.
References
- NIH Office of Dietary Supplements Dietary Supplement Fact Sheet:Calcium
- "Journal of the American College of Nutrition"; Absorbability and Cost Effectiveness in Calcium Supplementation
- UpToDate: Patient information: Calcium and vitamin D for bone health
- New York State Department of Health: Commonly Asked Questions About Calcium Supplements
