Jairoun et al. 2020 — Heavy metals in UAE dietary supplements

Summary

This is a large primary occurrence-and-exposure survey of toxic metals in dietary supplements, a product category the HMTc program covers. The authors measured cadmium, lead, and arsenic by ICP-MS in 277 supplement products sampled from the United Arab Emirates market and combined each product’s metal concentration with its labelled daily dose to estimate daily metal intake against acceptable-daily-intake (ADI) reference values. The headline finding is reassuring on average but informative on structure: mean daily intakes were well below ADI for all three metals (Cd 0.73 of 6 µg, Pb 0.85 of 20 µg, As 0.67 of 10 µg), yet 3 of 277 products (1.1%) individually exceeded an ADI (two for cadmium, one for lead). The more useful contribution for the Index is the contamination-determinant structure: cadmium and arsenic intake rose significantly with herbal/probiotic/enzyme/fatty-acid formulations and with powder/liquid and soft-gel dosage forms, while lead was significantly higher in India-manufactured products. The authors read this as formulation, dosage form, and country of origin being strong determinants of supplement metal contamination — a directly actionable pattern for category screening.

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 As (no speciation).

• Overall 3 of 277 products (1.1%, 95% CI −0.14 to 2.3) exceeded an ADI for Cd, 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 (β = 1.65) and soft-gel (β = 0.52) forms and herbal/probiotic/enzyme/fatty-acid blends (p < 0.001).
• 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 supplements-botanicals-herbs, anchoring Cd/Pb/As daily-intake distributions and the formulation/dosage-form/origin determinants.
• The herbal-and-botanical + powder/liquid + soft-gel signal for Cd and As, and the India-origin signal for Pb, are concrete screening levers for any future certification of the supplement category.
• Contributes cadmium, lead, and arsenic occurrence in supplements with a quantified low-exceedance rate (1.1%).

Wiki pages this source may touch

• dietary-supplements and supplements-botanicals-herbs — Cd/Pb/As daily-intake distribution and contamination determinants.
• cadmium — herbal/probiotic formulation and soft-gel/powder association.
• lead — India-origin association.
• arsenic — powder/liquid and soft-gel association.

Verification notes

• Values from Table 2 (overall daily intake) and Tables 3–6 (determinant regressions). Table 2’s header label “µg/g” conflicts with the body text and ADI comparison, which are in µg/day intake; the abstract and Results consistently state µg/day, so daily intake (µg/day) is recorded here and the “µg/g” header is treated as a typographical error.
• Reported metric is daily intake (concentration × labelled dose), not raw µg/g concentration, so this is occurrence expressed through an exposure lens; underlying per-product µg/g concentrations are not separately tabulated.
• No brand-by-brand data: results are aggregated by formulation category, dosage form, and country of origin; the Part 12 firewall is satisfied at the source.
• Speciation: total As by ICP-MS; no inorganic-As fraction reported.

Page history

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