Overview
Yao and colleagues analyzed 82 calcium supplements from the Chinese market for arsenic, lead, cadmium, chromium, aluminum and mercury, plus calcium, and compared the results with Chinese limits and JECFA tolerable intakes. Table 1 reports mean, SD and range by dosage form. Tablets carried the highest lead and chromium; soft capsules the highest arsenic and aluminum.
Key numbers
- Lead: all samples 0.88 ± 1.50 mg/kg (range 0.001 to 8.49); tablets 1.28 ± 1.71 mg/kg; 9 of 82 above 2 mg/kg (Table 1).
- Arsenic: all samples 1.95 ± 3.18 mg/kg (maximum 15.34, in a tablet); soft capsules 4.21 ± 3.80 mg/kg (Table 1).
- Cadmium: all samples 0.05 ± 0.15 mg/kg (ND to 1.10); 6 of 82 above 0.1 mg/kg (Table 1).
- Mercury detected in 11 of 80 samples, maximum 0.04 mg/kg (Table 1).
Methods (brief)
Tablets were ground; 0.2 g of solid or 2 mL of liquid was microwave-digested in nitric acid. Lead, cadmium, chromium and arsenic by ICP-MS with rhodium internal standard, aluminum by ICP-AES, mercury by cold-vapor AAS. No reference material, recoveries or detection limits are reported.
Evidence Fitness
A reasonably large market sample of finished calcium supplements, but no CRM or LOD, and some table totals conflict with the text (for example the total arsenic minimum). Oral liquid results are labeled mg/kg although liquids were sampled by volume. These are finished calcium supplements, so for the vitamin-mineral-premix page this is a proxy (finished product, not premix) and that page is not linked.