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Magnesium in tap and bottled mineral water in Spain and its contribution to nutritional recommendations

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Summary

Ion chromatography analysis of 108 Spanish municipal tap waters (representing 21,290,707 potential consumers) and 109 bottled natural mineral waters (97 Spanish brands, 12 imported) sold in Spain. The study characterizes magnesium concentrations and estimates the percentage of dietary reference intakes that drinking water can contribute across age groups. It is a nutritional adequacy study, not a contamination or safety study.

Key numbers

  • Tap water (108 municipalities): average 14.65 +/- 16.23 mg/L (range 0.07 to 70.08 mg/L); 25 municipalities had 15 to 45 mg/L; 7 had over 45 mg/L (p. 1 abstract)
  • Spanish bottled mineral water (97 brands): average 16.27 mg/L (range 0.11 to 141.2 mg/L); 33 brands contained 15 to 45 mg/L; 4 contained over 45 mg/L (p. 1 abstract)
  • Imported bottled water (12 brands): 4 contained over 45 mg/L (p. 1 abstract)
  • Dietary reference contribution from water containing 15 to 45 mg/L (assuming EFSA-recommended water consumption): 9 to 76.5% of recommended intake for children aged 1 to 13; up to 25.7% for adolescents; 7.5 to 25.7% for adults; up to 27% for lactating women (p. 1 to 2 abstract)
  • Water containing 60 mg/L provides 30 to 102% of recommended dietary allowance depending on age (p. 2 abstract)
  • An EU bottled water label may claim “rich in magnesium” if the product contains more than 50 mg/L (p. 1 methods)

Evidence Fitness

Modeled or limited evidence. Provides measured concentration ranges for a large national sample of Spanish drinking and bottled waters. Percentage-of-RDI calculations are modeled from assumed consumption volumes and do not represent direct intake measurements. Single-country cross-sectional data; not generalizable as a global magnesium exposure estimate.

Methods (brief)

Ion chromatography (not further specified in abstract). Tap water sampled from 108 Spanish municipalities in 2012. Bottled water: commercial samples collected from retail. No LOD/LOQ reported in abstract. No digestion described for water samples; direct injection for ionic analysis is standard for water.

Implications

  • Courses: illustrates that drinking water can contribute meaningfully to magnesium intake in hard-water regions, and that the contribution is highly variable by geography.
  • App: no contamination_profile implication; magnesium is a nutritional analyte here, not a hazard analyte.
  • Microbiome: no direct connection.

Provenance notes

Open access (cc-by). Automated download via OpenAlex OA location. SHA256 verified against MANIFEST.csv.

Update history

No substantive edit history is available in this build. The full commit record is available in git.

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