Overview
The study compared cadmium, lead and mercury in 93 vitamin and vitamin-mineral dietary supplement products from Polish pharmacies, split between those containing plant raw materials (n=50) and those containing only synthetic ingredients (n=43). Key finding: supplements with plant components contained significantly higher cadmium and lead than purely synthetic preparations; four plant-containing products exceeded the mercury limit of 0.1 mg/kg.
Key numbers
Overall ranges across all 93 samples:
- Cadmium: 0.010 to 0.710 mg/kg (10 to 710 µg/kg)
- Lead: 0.02 to 1.55 mg/kg (20 to 1550 µg/kg)
- Mercury: 0.0005 to 0.1470 mg/kg (0.5 to 147 µg/kg)
By supplement type (Table 4, mg/kg):
| Type | n | Cadmium mean +/- SD | Lead mean +/- SD | Mercury mean +/- SD |
|---|---|---|---|---|
| Calming (plant) | 15 | 0.324 +/- 0.125 | 0.42 +/- 0.21 | 0.0071 +/- 0.0036 |
| Hair/nails/skin (plant) | 25 | 0.443 +/- 0.154 | 0.94 +/- 0.37 | 0.0068 +/- 0.0026 |
| Slimming (plant) | 10 | 0.49 +/- 0.182 | 0.75 +/- 0.30 | 0.0092 +/- 0.0044 |
| Vitamin-mineral (no plant) | 43 | 0.036 +/- 0.025 | 0.29 +/- 0.19 | 0.0010 +/- 0.0005 |
LOD/LOQ (Table 3): cadmium (Cd) LOQ 0.003 mg/kg, LOD 0.0025 mg/kg; lead (Pb) LOQ 0.02 mg/kg, LOD 0.012 mg/kg; mercury (Hg) LOQ 0.0005 mg/kg, LOD 0.0002 mg/kg.
Plant-containing preparations had significantly higher cadmium (mean 0.253 +/- 0.193 mg/kg vs 0.036 +/- 0.025 mg/kg, p=0.004) and lead (p=0.032). Mercury difference was not statistically significant (p=0.088). Four plant-containing preparations exceeded the EU mercury limit of 0.1 mg/kg. No sample exceeded the cadmium limit (1.0 mg/kg) or lead limit (3.0 mg/kg). EU limits applied: Regulation (EU) No 2023/915.
Methods (brief)
Cadmium and lead by flame AAS (HITACHI Z-2000; PN-EN 14082:2004 after dry mineralization at 420 degrees C, acid dissolution). Mercury by direct AAS with amalgamation on AMA-254 analyzer with no prior mineralization (0.1 g sample fed directly). Method validated with INCT-MPH-2 Mixed Polish Herbs reference material; recoveries approximately 98 to 99 percent.
Evidence Fitness
Well-validated analytical methods with stated LOD and LOQ and reference material confirmation. The plant-component split is the principal analytical contribution to the index; this is a herbal/vitamin supplement dataset, not a protein powder dataset. Protein-based products (whey, casein) are absent; the study population is predominantly tablet and capsule vitamin-mineral preparations. Contributes to the broader dietary supplement context for the index rather than to the core whey or protein-powder occurrence evidence.
Related evidence
- Non-soy protein sources
- Herbal botanicals
- Ingredient class — protein/collagen powders
- Lead
- Cadmium
- Mercury
- Importance of Public Health Control of Metals as Chemical Risks in Dietary Supplements
Update history
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