No changes in serum enterolactone levels after eight weeks’ intake of ryebran products in healthy young men

Abstract

Background: Enterolactone (ENL) is a mammalian lignan metabolized by the colonic bacterial flora from plant lignan precursors widely distributed in plant foods. Objective: The aim of the study was to identify the point in time at which the onset of an increase in ENL concentration could be observed, and the point in time at which a stable level of ENL concentration was obtained. Design: Sixteen young healthy male volunteers, 25.8±4.0 years of age (mean±SD) and with an average body mass index of 23.4±2.1 kg m-2 completed this 8 week intervention study. Subjects were randomly assigned to two groups receiving 315±10 g of enriched bread and muffin products daily, containing either rye bran, rich in ENL precursors, or Vitacel 600®, a purified cellulose fibre, low in ENL precursors. Eleven fasting blood samples from each subject were taken for analysis of serum ENL concentration. Results: Serum ENL concentration was not affected by the daily supplementation with ry e bran and no significant difference in serum ENL concentration was observed between the groups receiving rye bran or Vitacel products after 8 weeks. A significant decrease in ENL concentration was observed in the Vitacel group after 1 day (p=0.018) and 1 week (p=0.029) of dietary intervention. Conclusions: In an 8 week period no increase in ENL concentration was observed for the rye-bran group and a stable level of ENL concentration was not obtained. The high intake of dietary fibre from the bread products possibly decreased transit time, and thereby reduced microbial fermentation of the plant lignans and absorption of the mammalian lignan ENL. Keywords: dietary fibre; lignan; transit time