Heavy Metal contamination of Dietary Supplements products available in the UAE markets and the associated risk

Summary

Key numbers

Values are estimated daily metal intake (µg/day) = product concentration (µg/g) × labelled daily dose, by ICP-MS. ADI as cited by the authors (American Herbal Products Association guidance). Arsenic is total arsenic (As) (no speciation).

• Overall 3 of 277 products (1.1%, 95% CI −0.14 to 2.3) exceeded an ADI for cadmium (Cd), lead (Pb), and/or As.
• Cadmium intake rose significantly (p < 0.001) with herbs+probiotics+enzymes+fatty-acid formulations (β = 0.876) and herbs+vitamins+minerals+fatty-acids+enzymes (β = 0.725); and with powder/liquid and soft-gel forms (p = 0.030).
• Lead intake was significantly higher in India-made products (multivariate β = 1.599, p < 0.001) and lower in capsule form (β = −0.75, p = 0.002).
• Arsenic intake rose with powder/liquid form (β = 1.65, p < 0.001), soft-gel form (β = 0.52, p = 0.003), and herbal/probiotic/enzyme/fatty-acid blends (β = 0.53, p = 0.005).
• LOQ 50 µg/g (Pb, As), 10 µg/g (Cd); validated spike recovery 80–120%, RSD < 20%.

Methods (brief)

ICP-MS (Agilent 7700X) with He collision/reaction cell after CEM MARS-5 microwave acid digestion (HNO₃ + H₂O₂ + HCl). Random-selection sampling of 277 orally-taken supplements across UAE outlets. Per-product concentration converted to daily intake via labelled adult dose; means/medians compared to ADI; univariate and multivariate linear regression for contamination determinants (formulation category, dosage form, country of origin). QC: reagent blanks, matrix spikes every 15 samples, calibration verification every 10–15 samples.

Implications

• Primary, large-n (277) occurrence/exposure dataset for Dietary Supplements and Ingredient class — botanicals/herbs/traditional formulas, anchoring Cd/Pb/As daily-intake distributions and the formulation/dosage-form/origin determinants.
• Identifies formulation (herbal/probiotic/enzyme/fatty-acid blends), dosage form (powder/liquid and soft-gel), and country of origin (India for Pb) as covariates significantly associated with metal intake from supplements in this sample.
• Contributes Cadmium, Lead, and Arsenic occurrence in supplements with a quantified low-exceedance rate (1.1%).

Update history

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