Overview
The Citizens Protein Project sent 36 blinded, number-coded protein supplements to an accredited laboratory for protein, aflatoxin, pesticide, heavy-metal and solvent screening. Lead was quantified in 27 products, cadmium in 10 and arsenic in 5; mercury and thallium were below quantification in all.
Key numbers
- Lead up to 0.32 mg/kg (product 27) and 0.31 mg/kg (product 25); cadmium up to 0.047 mg/kg (product 8); arsenic up to 0.085 mg/kg (product 28) (Table 1, p. 4).
- Copper 1.49 to 30.61 mg/kg (Table 1).
- Limit of quantification 0.025 mg/kg for all heavy metals (Table 1 footnote).
Methods (brief)
ICP-MS for arsenic, cadmium, lead, mercury, thallium and copper by an FSSAI-approved laboratory; detailed method in supplementary documents that were not available.
Evidence Fitness
Per-product values for 36 products, but the protein type of each code is only in a supplementary master chart, so whey, plant and blended products cannot be separated. The set mixes soy-containing blends with other proteins, so it is a proxy for non-soy protein sources and meal-replacement drinks, not a direct measurement of either.