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Contribution of dietary protein and inorganic sulfur to urinary sulfate: toward a biomarker of inorganic sulfur intake.
Am J Clin Nutr 2004; 80(1):137-42AJ

Abstract

BACKGROUND

Sulfiting agents are widely used as food additives. Limits are set on their use in foods because they may adversely affect health. Sulfiting agents are excreted in urine as sulfate, which is indistinguishable from sulfate derived from sulfur amino acids.

OBJECTIVE

The objective was to assess the contribution of inorganic sulfur to urinary sulfate excretion and of dietary protein to urinary sulfate and nitrogen excretion with the aim of developing a urinary biomarker of inorganic sulfur intake.

DESIGN

Nine healthy men were fed a sequence of 3 diets for 15 d (n = 7), 5 diets for 10 d (n = 6), or both. The diets contained 51-212 g protein/d (0.43-1.71 g S/d) and 0.17-0.27 g inorganic S/d; p-aminobenzoic acid-validated 24-h urine samples (n = 47) were analyzed for sulfate and nitrogen.

RESULTS

Dietary inorganic sulfur was efficiently excreted as sulfate in urine. Urinary sulfate derived from protein correlated strongly (r(2) = 0.86) with urinary nitrogen. Urinary recovery of protein sulfur and nitrogen decreased from 84% at average protein intakes (72 g/d) to 70% at high protein intakes (212 g/d). The nitrogen:sulfur ratio (in g) of the protein in the study diets was 18.9, which was maintained in urine (18.4 +/- 0.1) after dietary inorganic sulfur intake was subtracted from urinary sulfate. Therefore, inorganic sulfur intake (g/d) = urinary sulfur (g/d) - 0.054 x urinary nitrogen (g/d). For typical UK intakes of inorganic sulfur (0.25 g/d), this biomarker should produce mean (+/- SD) values of 0.24 +/- 0.10 g S/d.

CONCLUSION

Twenty-four-hour urinary nitrogen and sulfate values can be used to predict inorganic sulfur intake.

Authors+Show Affiliations

Department of Molecular and Cellular Pathology, Ninewells Hospital and Medical School, Dundee, United Kingdom. e.magee@dundee.ac.ukNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Clinical Trial
Journal Article
Randomized Controlled Trial
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

15213040

Citation

Magee, Elizabeth A., et al. "Contribution of Dietary Protein and Inorganic Sulfur to Urinary Sulfate: Toward a Biomarker of Inorganic Sulfur Intake." The American Journal of Clinical Nutrition, vol. 80, no. 1, 2004, pp. 137-42.
Magee EA, Curno R, Edmond LM, et al. Contribution of dietary protein and inorganic sulfur to urinary sulfate: toward a biomarker of inorganic sulfur intake. Am J Clin Nutr. 2004;80(1):137-42.
Magee, E. A., Curno, R., Edmond, L. M., & Cummings, J. H. (2004). Contribution of dietary protein and inorganic sulfur to urinary sulfate: toward a biomarker of inorganic sulfur intake. The American Journal of Clinical Nutrition, 80(1), pp. 137-42.
Magee EA, et al. Contribution of Dietary Protein and Inorganic Sulfur to Urinary Sulfate: Toward a Biomarker of Inorganic Sulfur Intake. Am J Clin Nutr. 2004;80(1):137-42. PubMed PMID: 15213040.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Contribution of dietary protein and inorganic sulfur to urinary sulfate: toward a biomarker of inorganic sulfur intake. AU - Magee,Elizabeth A, AU - Curno,Richard, AU - Edmond,Laurie M, AU - Cummings,John H, PY - 2004/6/24/pubmed PY - 2004/7/14/medline PY - 2004/6/24/entrez SP - 137 EP - 42 JF - The American journal of clinical nutrition JO - Am. J. Clin. Nutr. VL - 80 IS - 1 N2 - BACKGROUND: Sulfiting agents are widely used as food additives. Limits are set on their use in foods because they may adversely affect health. Sulfiting agents are excreted in urine as sulfate, which is indistinguishable from sulfate derived from sulfur amino acids. OBJECTIVE: The objective was to assess the contribution of inorganic sulfur to urinary sulfate excretion and of dietary protein to urinary sulfate and nitrogen excretion with the aim of developing a urinary biomarker of inorganic sulfur intake. DESIGN: Nine healthy men were fed a sequence of 3 diets for 15 d (n = 7), 5 diets for 10 d (n = 6), or both. The diets contained 51-212 g protein/d (0.43-1.71 g S/d) and 0.17-0.27 g inorganic S/d; p-aminobenzoic acid-validated 24-h urine samples (n = 47) were analyzed for sulfate and nitrogen. RESULTS: Dietary inorganic sulfur was efficiently excreted as sulfate in urine. Urinary sulfate derived from protein correlated strongly (r(2) = 0.86) with urinary nitrogen. Urinary recovery of protein sulfur and nitrogen decreased from 84% at average protein intakes (72 g/d) to 70% at high protein intakes (212 g/d). The nitrogen:sulfur ratio (in g) of the protein in the study diets was 18.9, which was maintained in urine (18.4 +/- 0.1) after dietary inorganic sulfur intake was subtracted from urinary sulfate. Therefore, inorganic sulfur intake (g/d) = urinary sulfur (g/d) - 0.054 x urinary nitrogen (g/d). For typical UK intakes of inorganic sulfur (0.25 g/d), this biomarker should produce mean (+/- SD) values of 0.24 +/- 0.10 g S/d. CONCLUSION: Twenty-four-hour urinary nitrogen and sulfate values can be used to predict inorganic sulfur intake. SN - 0002-9165 UR - https://www.unboundmedicine.com/medline/citation/15213040/Contribution_of_dietary_protein_and_inorganic_sulfur_to_urinary_sulfate:_toward_a_biomarker_of_inorganic_sulfur_intake_ L2 - https://academic.oup.com/ajcn/article-lookup/doi/10.1093/ajcn/80.1.137 DB - PRIME DP - Unbound Medicine ER -