Determinants of plasma alkylresorcinol concentration in Danish post-menopausal women.

Background: Alkylresorcinols (AR), a group of phenolic lipids present in the outer parts of wheat and rye grain kernels, have been suggested as biomarkers of whole-grain wheat and rye intake. In this study, we investigated potential determinants of plasma AR concentration in a free-living population.

Subjects/methods: Non-fasting samples from post-menopausal women enrolled in the Danish Diet, Cancer and Health study (n = 360) were selected. Diet was assessed using a semi-quantitative food frequency questionnaires (FFQ) and the association between food items likely to contain AR and relevant non-dietary factors were studied by analysis of covariance models.

Results: The median AR concentration was 78 nmol/l (interquartile range = 106.9 nmol/l). Intake of rye bread, identified as the main determinant, was associated with 87% higher plasma total AR concentration per 100 g of bread (95% confidence interval = 46-139%). About 8-12% of the total variation (depending on the AR homologue) in plasma AR concentration was explained by the selected dietary variables. At a nutrient level, total dietary fiber and cereal fiber were significantly associated with plasma total AR concentration (P = 0.05), but only ≈2% of the total plasma AR concentration was explained by the dietary fiber or cereal fiber intake.

Conclusions: In the studied population, AR plasma concentration was mainly affected by rye bread intake among investigated determinants.