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Heavy Metal Index

Diet, but not food type, significantly affects micronutrient and toxic metal profiles in urine and/or plasma; a randomized, controlled intervention trial

Overview

Rempelos and colleagues ran a randomized, controlled diet switch-over trial measuring urinary excretion and plasma concentrations of micronutrients, phenolic markers, and toxic metals. The source is exposure-biomarker evidence, not a product-occurrence survey: it reports urinary aluminum (Al), cadmium (Cd), nickel (Ni), lead (Pb) and related diet-driver modelling, but it does not report contaminant concentrations in coffee, fish, organic foods, or other market products.

The auto-fetch filename assigned this PDF to a coffee cadmium gap because coffee was one of the dietary drivers in the redundancy analysis. The paper itself is broader human biomonitoring evidence for diet-linked metal excretion, with products and ingredients intentionally left empty.

Key numbers

  • Study design: 27 healthy adults, randomized to conventional-food Mediterranean diet (n = 14) or organic-food Mediterranean diet (n = 13), within a 5-week switch-over from habitual Western diet to Mediterranean diet and back to Western diet.
  • Monitored urine toxic metals included Al, Ba, Be, Cd, Ni, Pb, and Sb; Ba, Be, and Sb were below the limit of detection in most samples and were not reported.
  • No significant main effects of food type were detected for the urine or plasma parameters when organic and conventional Mediterranean-diet periods were compared.
  • Western diet to Mediterranean diet urinary Ni: 59 (55, 63) nmol/d in week 1 to 84 (77, 91) nmol/d in week 3; P = 0.0005, Holm-adjusted P = 0.0060.
  • Western diet to Mediterranean diet urinary Pb: 2.7 (2.4, 2.8) nmol/d in week 1 to 3.7 (3.3, 4.0) nmol/d in week 3; P = 0.0065, Holm-adjusted P = 0.0610.
  • Western diet to Mediterranean diet urinary Al: 267 (218, 316) nmol/d in week 1 to 285 (238, 333) nmol/d in week 3; P = 0.7862.
  • Western diet to Mediterranean diet urinary chromium (Cr): 7.9 (7.4, 8.4) nmol/d in week 1 to 9.6 (9.0, 10.2) nmol/d in week 3; P = 0.0166, Holm-adjusted P = 0.1162.
  • Mediterranean diet to Western diet urinary Ni: 84 (77, 91) nmol/d in week 3 to 71 (62, 80) nmol/d in week 5; P = 0.2553.
  • Mediterranean diet to Western diet urinary Pb: 3.7 (3.3, 4.0) nmol/d in week 3 to 3.8 (3.3, 4.2) nmol/d in week 5; P = 0.7700.
  • Mediterranean diet to Western diet urinary Al: 285 (238, 333) nmol/d in week 3 to 244 (184, 305) nmol/d in week 5; P = 0.5044.
  • Redundancy analysis explained 33.6% of the variation in urinary phenolic, micronutrient, and metal excretion; axis 1 explained 19% and axis 2 explained 6%.
  • Stronger dietary drivers in the RDA were vegetables (F = 10.2; P = 0.002), coffee (F = 4.0; P = 0.006), wine (F = 2.2; P = 0.062), fish (F = 2.2; P = 0.080), tea (F = 1.9; P = 0.088), and fruits/fruit juice (F = 1.7; P = 0.124).
  • The RDA text identifies fish, and to a lesser extent refined-cereal grain products, as more closely associated with urinary Mo, Cd, and Pb. The figure caption reports food type itself as weak: conventional F = 0.9, P = 0.49; organic F = 0.9, P = 0.49.

Methods (brief)

The trial recruited 27 students during an agricultural field course in Crete. Participants consumed habitual self-selected Western diets made from conventional foods before and after the intervention period. During the 2-week intervention, one randomized group consumed the defined Mediterranean diet made from conventional foods and the other group consumed the same Mediterranean diet made from EU-certified organic foods.

Participants completed three 7-day food diaries. Mineral micronutrients and toxic metals in urine and plasma were measured by the Health & Safety Laboratory using standard protocols. Statistical analysis used mixed-effect models with participant as a random factor, Holm-adjusted P values, and exploratory redundancy analysis to relate diet components and food type to urinary-excretion profiles.

Implications

Microbiome: No microbiome findings.

Update history

The five most recent substantive edits to this page, classified major (evidence or structure moved), correction (a published value or statement was wrong and has been fixed), or minor (narrative rewritten without changing the underlying evidence). Each description is derived from what the edit did to this page; the linked commit is the authoritative record, routine regeneration passes are excluded, and the full version history lives in git. When DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.

CommitDateChangeDescription
b01ec52c32026-08-04major1 section added
3171d069e2026-08-02major1 section added
90a2f9a382026-07-30major1 section added and 1 removed; narrative text revised
eaa8eeeed2026-07-27major1 section added
50de6ab212026-07-27minorNarrative text revised