Calcium Supplements The demand for calcium supplements is reflected by retail sales data. In 1993, calcium supplements accounted for 6.7% of total supplement sales or $245 million a year in the U.S.. Between 1994 and 1999, sales for calcium supplements increased 60%. Reasons why individuals take calcium supplements are varied and include: concerns about the adequacy of the calcium content of their diets; perceived or actual milk protein allergy/lactose intolerance; and a desire to provide insurance against calcium deficiency or to treat or prevent disease. Calcium is  found in many foods and adequate calcium intake is important because the human body cannot produce calcium. Even after reaching full skeletal growth, adequate calcium intake is important because the body loses calcium every day through shedding skin, nails, hair, and sweat as well as through urine and feces. This lost calcium must be replaced daily through the diet. When the diet does not contain enough calcium to perform these activities, calcium is taken from the bones, the storage area for calcium. The National Academy of Sciences and the National Osteoporosis Foundation recommend daily calcium intakes of 1000-1200 mg/day for adult men and women. According to experts, food is the best source of calcium; however, most Americans do not have enough calcium in their diets. Fortunately, calcium-fortified foods and calcium supplements can fill the gap, ensuring that the daily calcium requirement is met. The amount needed from a supplement depends on how much calcium is consumed from food sources. According to a recent review of calcium preparations, there are at least a dozen common calcium preparations and hundreds of different formulations available. Calcium carbonate is the most common preparation; some others include tricalcium phosphate, dicalcium phosphate, bone meal, calcium citrate-malate, oyster shell, calcium lactate, and calcium gluconate. These calcium preparations differ in a variety of ways. Calcium carbonate has the highest concentration of calcium by weight (40%), whereas calcium citrate has 21% calcium and calcium phosphate has 8% calcium by weight. Although calcium carbonate has the highest concentration of calcium by weight, this form of calcium is relatively insoluble, especially at a neutral pH. In contrast, calcium citrate, although containing about half as much calcium by weight, is a more soluble form of calcium. Because calcium citrate does not require gastric acid for absorption, it is a better choice for patients with achlorhydria (i.e., limited gastric acid production). In addition to the amount (dosage) of calcium in various supplements, the solubility and absorption of calcium must be considered.  Prior to absorption, calcium preparations must dissociate into elemental calcium. The more soluble a calcium supplement product is in vitro (i.e., measured by the ability to dissolve in 6 ounces of vinegar within 30 minutes), the more soluble the calcium preparation is in the body. While dosage and solubility can influence the bioavailability of calcium from calcium supplements, the timing of intake and meal conditions also are important. Calcium from supplements appears to be more efficiently absorbed when consumed in divided doses, each containing less than 200 mg of elemental calcium. The NIH Consensus Conference recommends consuming calcium supplements between meals to increase calcium bioavailabilty. The long-term safety of consuming large doses of single nutrients including calcium is of concern. Although calcium intakes up to 2,000 mg/day appear to be safe for most individuals, potential adverse effects can occur as a result of chronic high intakes or intakes of specific calcium preparations. Potential adverse effects include gastrointestinal problems such as constipation. Certain preparations of calcium (e.g., bone meal, dolomite) may contain contaminants such as lead, aluminum, arsenic, mercury, and cadmium. Significant amounts were identified in calcium carbonate supplements labeled oyster shell or natural source. Chronic intake of these supplements may pose an unnecessary risk. Most commercial calcium preparations are tested for heavy metal contamination. High intakes of calcium supplements may interfere with the absorption of other nutrients such as iron and zinc. Intake of calcium supplements also may interfere with the absorption of concurrently consumed medications, and vice versa. Other potential adverse effects of chronic intakes of high doses of calcium include milk-alkali syndrome (ectopic calcium deposition), hypervitaminosis D (i.e., in the case of supplements containing calcium and vitamin D), and possible hypercalciuria leading to kidney stone formation. However, recent studies indicate that increased intake of calcium does not increase risk of kidney stones. Moreover, restricting dietary calcium may increase urinary excretion of oxalate which in turn increases risk of kidney stones. For certain individuals who cannot meet their calcium needs from foods, calcium supplements are warranted. However as reviewed above, a number of factors influence the choice of calcium preparation. Individuals who need calcium supplements should choose one that contains a relatively high percentage of elemental calcium by weight, disintegrates readily, provides a form of calcium that is bioavailable and inexpensive, is manufactured by a reputable pharmaceutical company, and is free of toxicants. In general, absorption of calcium is most efficient when the supplement is consumed in doses of 200 mg or less. Intake of calcium supplements with vitamin D should be limited because of the risk for vitamin D toxicity. Absorbability Calcium products are generally absorbed easily in the body. Tablets and pills are not the best solution for an added intake of calcium, as they vary in their ability to be fully digested. How well a tablet dissolves can be determined by placing it in a small amount of warm water for 30 minutes, stirring it occasionally. If it hasn’t dissolved within this time it probably will not dissolve in the stomach. Liquid calcium supplements dissolve well because they are broken down before they enter the stomach. There are some "high tech" calcium supplements available that must be mixed in a liquid, than drunk.  These deliver nearly 100% of their available mineral solution as they are in a nearly "pre-digested" state. Calcium, whether from the diet or supplements, is absorbed best by the body when it is taken several times a day in amounts of 200 mg or less, but taking it all at once is better than not taking it at all. Calcium carbonate is absorbed best when taken with food. Calcium citrate can be taken any time. Tolerance While calcium supplements generally are a satisfactory option for many people, certain preparations may cause side effects, such as gas or constipation, in some individuals. If simple measures such as increased fluids and fiber intake do not solve the problem, another form of calcium should be tried. Also, it is important to increase supplement intake gradually; take 200 mg a day for a week, then add more calcium slowly. Calcium Interactions It is important to talk with a physician or pharmacist about possible interactions between prescription or over-the-counter medications and calcium supplements. For example, calcium supplements also may reduce the absorption of the antibiotic tetracycline. Calcium also interferes with iron absorption, so a calcium supplement should not be taken at the same time as an iron supplement. The exception to this is when the iron supplement is taken with vitamin C or calcium citrate. Any medication to be taken on an empty stomach should not be taken with calcium supplements. Combination Products Calcium supplements are available in a dazzling array of combinations with vitamins and other minerals. While vitamin D is necessary for the absorption of calcium, it is not necessary that it be in the calcium supplement. Minerals such as magnesium and phosphorus also are important, but usually are obtained through food or multivitamins. Most experts recommend that nutrients come from a balanced diet, with multivitamins used to supplement dietary deficiencies. Most published studies show that low calcium intake is associated with low bone mass, rapid bone loss and high fracture rates. Adequate calcium intake will help ensure that calcium deficiency is not contributing to a weakening of the skeleton.   Back to Calcium Information Return to the main Calcium page Back to Nutritional page. Question? Email us!   "These statements have not been evaluated by the FDA. This product is not intended to diagnose, cure, prevent or treat any diseases." The above is a Government ORDERED statement. It is NOT based in either reality or sanity. Just like our Government. In a landmark decision on Friday, Jan. 15, 1999, the US Court of Appeals for the District of Columbia ruled that the health claim rules imposed by the FDA unconstitutional and in violation of the Administrative Procedure Act. The court instructed the FDA to define "significant scientific agreement" for health claims on dietary supplement labels, and instructed the FDA to allow the use of disclaimers on labels rather than to suppress these claims outright. The court further held that four FDA Final rules (prohibiting certain nutrient disease relationship claims) invalid under the first Amendment to the Constitution.