Plasma pharmacokinetics of alkylresorcinol metabolites: new candidate biomarkers for whole-grain rye and wheat intake12

• Published in: The American journal of clinical nutrition Vol. 90; no. 5; pp. 1167 - 1171
• Main Authors: Söderholm, Päivi P, Koskela, Anja H, Lundin, Johan E, Tikkanen, Matti J, Adlercreutz, Herman C
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.11.2009
• ISSN: 0002-9165; 1938-3207
• DOI: 10.3945/ajcn.2009.28290

Alkylresorcinols are phenolic compounds that are present almost exclusively in rye and wheat fiber. Alkylresorcinols are absorbed and thereafter metabolized to 3,5-dihydroxybenzoic acid (DHBA) and 3-(3,5-dihydroxyphenyl)-1-propanoic acid (DHPPA), which have been detected in human urine and plasma. The objective was to determine the plasma pharmacokinetics of DHBA and DHPPA in human subjects to estimate whether they show potential as biomarkers for whole-grain rye and/or wheat intake. Fifteen human volunteers followed a low-alkylresorcinol diet for 2 d before ingesting a single dose of high-fiber rye bread containing 45 mg alkylresorcinols. Plasma samples were collected for 25 h, and the alkylresorcinol metabolites were quantified by HPLC with coulometric electrode array detection. Maximum concentrations were reached at ≈6 h for both metabolites, although interindividual variation was found. The half-life was significantly (P &lt 0.0002) longer for DHPPA (16.3 h) than for DHBA (10.1 h). No significant differences were discovered between women and men in the half-life of each metabolite, which, from a pharmacokinetic point of view, is the most important parameter. The area under the curve differed significantly between DHBA and DHPPA (P &lt 0.0001) and between women and men (P = 0.03 for DHBA and P = 0.01 for DHPPA). However, when corrected for body weight, the difference between sexes was no longer significant. Our results suggest that DHBA and DHPPA are both good candidate biomarkers for whole-grain rye and/or wheat intake; however, DHPPA is the better indicator because of its longer half-life. This could provide a practical tool when investigating the association between diet and diseases.