CALCIUM SUPPLEMENTS: 25% OF 70 BRANDS EXCEED TOTAL DAILY LEAD INTAKE LEVELS
This article was originally published in The Tan Sheet
CALCIUM SUPPLEMENTS: 25% OF 70 BRANDS EXCEED TOTAL DAILY LEAD INTAKE LEVELS for children six and under, concluded Bernard Bourgoin, PhD, Trent University, Ontario, et al. in a study published in the August issue of the American Journal of Public Health. "Based solely on the ingestion" of calcium supplements, "the lead intake from about 25% of the calcium supplements (17 of 70 brands) exceeded the provisional total tolerable daily intake of 6" micrograms of lead set by FDA for children six and under. Bourgoin et al. underscored that the 6 mcg "value represents the maximum amount of lead to be ingested from all dietary sources." To conduct the study, the authors obtained 55 brands of calcium supplements from pharmacies, supermarkets and health food stores in Ontario and 15 additional brands from the California Department of Health Services. The supplement brands were grouped into five categories of calcium salts: refined calcium carbonate, natural source calcium carbonate, dolomite, calcium phosphate (bonemeal) or hydroxyapatite, and chelated calcium. Samples of all 70 brands were analyzed to determine the range and mean lead concentration for each supplement category. "High- purity, certified reagents" were used to detect the lead content in each brand, the study notes. The researchers tabulated the lead levels in the various forms of calcium supplements by multiplying the lead concentrations in an ashed powder form of the supplement sample by the ash content of the sample. Based on the suggested daily dosage listed on product labels, daily lead ingestion rates (micrograms of lead ingested per day) were calculated and compared to FDA's 1990 guidelines on dietary lead intake. Of the five calcium supplement categories, bonemeal calcium supplements registered the highest mean lead concentration -- 2.67 mcg of lead per gram of product dry weight. Bonemeal supplements were followed in mean lead concentration by natural source supplements (2.11 mcg/g), dolomite (1.11 mcg/g), refined supplements (.34 mcg/g) and chelates (.28 mcg/g). The researchers warned, however, that reporting lead levels in mcg/g "can be somewhat misleading because all the supplements contain varying amounts of binders or fillers and sometimes sugars" that may "dilute" or reduce the lead levels "because important amounts of these inert substances have been added." The "relative quality" of calcium supplements in terms of lead levels can be "compared more effectively," the study authors continued, "if the lead content in each brand is normalized to a set amount of the main active ingredient." Because young children "represent the segment of the population most sensitive to lead," the lead content for the 70 brands of calcium supplements was normalized to the Recommended Daily Allowance (RDA) of calcium for children -- 800 mg. Normalizing lead levels to the calcium RDA, the mean lead concentrations for the various types of calcium supplements were quite different, Bourgoin, et al. observed. For example, bonemeal was found to contain 11.33 mcg of lead per 800 mg of calcium, natural source calcium supplements contained 6.05 mcg/800 mg, dolomite 4.17 mcg/800 mg, chelates 1.64 mcg/800 mg, and refined calcium supplements .92 mcg/800 mg. The researchers concluded that "none of the products within the dolomite and bonemeal categories and only two brands of natural source calcium supplements could meet the Recommended Daily Allowance of calcium for young children while supplying a concomitant lead dose of 1 mcg or less." There was not a "significant difference in the lead levels between Canadian and American calcium supplements," Bourgoin, et al. added. Bourgoin et al. also observed that the suggested daily dosage of calcium for the 70 brands ranged from 180 mg (23% of the 800 mg RDA for children) to as high as 3,000 mg (375% of the RDA). "Consequently, many of the lead ingestion rates calculated" could be reduced "if lesser amounts of calcium supplements (i.e., dosages approximating 100% of the Recommended Daily Allowance for young children) were ingested," the study authors posited. Supplements containing below the 800 mg RDA, conversely, "could not be reduced to lower lead ingestion rates," they said. Based on the study findings, Bourgoin et al. recommended that sources of lead in calcium supplements be "identified and more rigidly controlled to prevent unnecessary exposure to dietary lead in all segments of the population, particularly young children." Reducing lead levels in calcium supplements is important, the Canadian researchers maintained, because "children who are intolerant to milk and dairy products . . . and who develop allergic reactions" to dairy products "can effectively meet their calcium requirements only through calcium supplementation." Supplements with high lead concentrations pose serious health risks to young children because they "assimilate ingested lead more efficiently than adults" and are "more sensitive to the low- level effects of lead." The researchers also pointed out that the Centers for Disease Control and Prevention has previously declared that lead "poisoning is one of the most common and most preventable pediatric health problems today." Another potential danger of calcium supplements with high lead concentrations is that bonemeal calcium powders are often used in high quantities by women over age 50 who seek "to prevent or retard degenerative changes (e.g., osteoporosis) through nutrition," Bourgoin, et al. said. As a powder, they continued, bonemeal calcium is often consumed in greater quantities than in tablet or capsule form. Other studies have also warned about the potential hazards of lead in calcium supplements. A study by Badi Boulos, MD/PhD, University of Illinois-Chicago School of Public Health, for instance, found that calcium supplements and antacids containing lead and other trace metals can cause health problems, particularly in older people due to their decreased rate of metabolism, kidney function and rate of elimination from the body ("The Tan Sheet" April 12, p. 9). FDA has initiated a broad-based effort to reduce lead levels in food where controllable or avoidable sources of lead can be identified. As part of this endeavor, FDA expects to issue a proposed rule in December outlining specifications for lead in calcium supplements that are generally recognized as safe, according to the agency's most recent regulatory agenda ("The Tan Sheet" May 10, p. 9).
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