Is there a relationship between tea intake and maternal whole blood heavy metal concentrations?

Overview

Colapinto and colleagues analysed tea intake against maternal whole-blood metals, cord-blood metals, and first-trimester urinary arsenic species in the Canadian MIREC cohort. This is lane a4 biomonitoring and dietary-exposure evidence, not a coffee or tea occurrence study. The strongest reported signal was for blood lead, especially green and herbal tea categories, while most adjusted mercury, cadmium, arsenic, and manganese comparisons were not significant for any tea versus no tea.

Key numbers

• Study cohort: 1,954 MIREC participants; metal results in Table 2 were available for 1,910 first-trimester blood samples, 1,673 third-trimester blood samples, and 1,398-1,399 cord-blood samples depending on analyte.
• First-trimester geometric means: lead 0.62 μg/dl; total mercury 2.99 nmol/l; cadmium 1.93 nmol/l; arsenic 9.75 nmol/l; manganese 160.1 nmol/l.
• First-trimester detection: lead 0% below LOD; total mercury 10% below LOD; cadmium 3% below LOD; arsenic 8% below LOD; manganese 0% below LOD.
• First-trimester blood lead by tea type, drinkers vs non-drinkers: regular tea 0.65 vs 0.61 μg/dl; green tea 0.75 vs 0.61 μg/dl; herbal tea 0.77 vs 0.61 μg/dl.
• Adjusted first-trimester blood lead LSGM for any tea: tea drinkers 0.65 μg/dl (95% CI: 0.62, 0.69) vs non-tea drinkers 0.61 μg/dl (95% CI: 0.59, 0.62), P = 0.0044.
• Adjusted first-trimester blood lead LSGM by tea type: green tea yes 0.71 μg/dl (95% CI: 0.65, 0.78) vs none to <1 cup/week 0.61 μg/dl (95% CI: 0.60, 0.62), P = 0.0007; herbal tea yes 0.71 μg/dl (95% CI: 0.63, 0.80) vs none to <1 cup/week 0.62 μg/dl (95% CI: 0.60, 0.63), P = 0.0195.
• Third-trimester adjusted blood lead LSGM: herbal tea yes 0.68 μg/dl (95% CI: 0.59, 0.78) vs none to <1 cup/week 0.56 μg/dl (95% CI: 0.55, 0.58), P = 0.0075.
• Cord-blood adjusted lead LSGM: herbal tea yes 0.92 μg/dl (95% CI: 0.77, 1.09) vs none to <1 cup/week 0.74 μg/dl (95% CI: 0.72, 0.76), P = 0.0144.
• Dose-response table for any tea and first-trimester blood lead: none to <1 cup/week 0.61 μg/dl (95% CI: 0.59, 0.62); 1 to <7 cups/week 0.65 μg/dl (95% CI: 0.61, 0.68), P = 0.0323; >=7 cups/week 0.67 μg/dl (95% CI: 0.62, 0.74), P = 0.0287.
• The authors state first-trimester 95th-percentile blood lead was 1.57, 1.65, and 1.76 μg/dl for regular, green, and herbal tea drinkers, respectively, versus 1.38 μg/dl for non-drinkers of each tea type.
• First-trimester urinary arsenic species, geometric means: trivalent arsenic <0.005 μmol/l; pentavalent arsenic <0.005 μmol/l; monomethylarsinic acid <0.005 μmol/l; dimethylarsinic acid 0.03 μmol/l; arsenobetaine/arsenocholine <0.005 μmol/l.
• First-trimester urinary dimethylarsinic acid by green tea: green-tea drinkers 0.05 μmol/l vs non-green-tea drinkers 0.03 μmol/l in Table 2; adjusted text reports green-tea LSGM 0.03 nmol/l (95% CI: 0.032, 0.035) vs non-green-tea drinkers 0.04 nmol/l (95% CI: 0.038, 0.049).
• The authors state the highest tea consumers still had geometric mean blood lead concentrations below 1 μg/dl.

Methods (brief)

Tea consumption was collected by questionnaire and categorized as regular, green, herbal, and all tea, with frequency grouped as none to <1, 1 to <7, and >=7 cups/week. Maternal whole blood in the first and third trimesters and cord blood were analysed by sample dilution followed by ICP-MS using an ICP-MS DRC-II Elan Perkin Elmer instrument. First-trimester urinary arsenic speciation used HPLC coupled to a Varian 820 MS ICP-MS. The Toxicology Laboratory at the Institut national de santé publique du Québec performed analyses under ISO 17025 and CAN-P-43 accreditation; values below LOD were assigned one-half the detection limit.

Implications

Microbiome: No microbiome endpoints.

Related evidence

• Lead
• Mercury, Total
• Cadmium
• Arsenic, Total
• Manganese

Update history

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