Rempelos et al. 2022 - Diet effects on urinary toxic-metal biomarkers

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 Al, Cd, Ni, 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 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

Certification: This paper should not enter any product occurrence or HMTc benchmark pool. It measures human urinary/plasma biomarkers after a dietary intervention and models dietary drivers; it does not measure contaminant concentrations in coffee, fish, wine, organic foods, or conventional foods.

Courses: Useful example of the distinction between product occurrence and exposure biomonitoring. The same dietary component can be an exposure driver without the paper providing a product concentration table.

App: Can support future exposure-context language that dietary pattern and seafood intake may move urinary metal biomarkers, but it does not justify a product-specific risk score.

Microbiome: No microbiome findings.

Wiki pages this source may touch

• lead
• cadmium
• nickel
• aluminum
• chromium
• index

Verification notes

• DOI, title, authors, journal, license, participant counts, study design, monitored metals, LOD statement, Table 2 urinary values, and RDA driver statistics were transcribed from the extracted PDF text.
• Units were kept as the source reports them: urinary metals in nmol/d and plasma values in micromol/L where relevant. No conversion to ug/L or mg/kg was made.
• The source reports unqualified urinary Pb, Cd, Ni, Al, and Cr biomarkers; no arsenic or mercury speciation issue applies.
• Products and ingredients are intentionally empty because the paper reports exposure biomarkers and diet-driver modelling, not market-product contamination values.

Page history

The five most recent substantive edits to this page. 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.