Dietary Determinants of Plasma Enterolactone

Enterolactone is a lignan produced by fermentation of dietary precursors in the human gut. Because lignan precursors are uniquely found in plant foods, plasma enterolactone concentration may serve as a biological marker of plant food consumption. This cross-sectional study examined associations of dietary intake with plasma enterolactone concentration. Weight-stable, 20–40-year-old volunteers (115 women and 78 men in Seattle, Washington) reporting intake of ≤2.5 or ≥4.5 fruit and vegetable servings/day and no antibiotic use for ≥3 months completed a food frequency questionnaire and 3-day food record. Time-resolved fluoroimmunoassay was used to measure plasma enterolactone. Based on diet records, plasma enterolactone was positively correlated with daily vegetable servings ( r = 0.17; P < 0.05), fiber ( r = 0.36; P < 0.0001), alcohol ( r = 0.24; P < 0.001), caffeine ( r = 0.21; P < 0.001), and daily botanical group servings [ Chenopodiaceae ( r = 0.15; P < 0.05), Juglandaceae ( r = 0.15; P < 0.05), Leguminosae ( r = 0.20; P < 0.001), Pedaliaceae ( r = 0.20; P < 0.001), and Vitaceae ( r = 0.20; P < 0.001)]. Fat-related variables were not correlated with plasma enterolactone. Based on linear regression models, plasma enterolactone increased by 37.0% (SE = 2.3%) for each 10-g increase in fiber and by 6.6% (SE = 0.2%) for each 50-mg serving of caffeine. Participants consuming 0.5–1 alcoholic drink/day had plasma enterolactone concentrations that were 131.4% (SE = 37.6%) higher than those of nondrinkers. Although plasma enterolactone may be useful as a biological measure of exposure to lignan-containing foods, it may be of limited use as a specific biomarker of fruit and vegetable or plant food intake because coffee, tea, and alcoholic beverages also significantly increase its plasma concentration.