Factors influencing interpersonal variability in plasma enterolactone concentration

Abstract: Lignans are biologically active diphenolic plant compounds with potential health affecting properties. Some epidemiological studies have demonstrated that a high lignan intake is associated with risk reduction of several chronic diseases such as breast, prostate and colorectal cancer as well as cardiovascular disease. The main sources of lignans are oil seeds (such as flaxseed and sesame seed), whole grains, legumes, vegetables, fruits, berries and some beverages such as coffee, tea and wine. The mammalian lignan enterolactone (ENL) is produced by the intestinal microflora in the upper part of the colon from dietary precursors, and are thereafter absorbed into the circulation. A wide range of plasma ENL concentrations have been observed in human experimental end epidemiological studies, and several factors related to diet and health has been associated with plasma ENL. The aim of this literature review was to identify and evaluate the relative contribution of factors influencing interpersonal variability in plasma enterolactone concentration based on literature extracte according to certain criteria defined by a working group in an ongoing COST-action initiative, the POSITIVe. The total number of human studies fulfilling the search criteria was 96. The main determinants of plasma ENL include lignan intake, intake of lignan-rich foods, composition and activity of intestinal microflora, antimicrobial use, nutrient intake BMI, smoking, sex and age. Composition and activity of the intestinal microbiota seem to be the most critical factor governing interpersonal variability in plasma ENL concentration. Intake of lignan-rich foods, constipation and lifestyle factors such as smoking and BMI explain only a small part of the variation, whereas antimicrobials have a more pronounced effect on plasma ENL. The impact of sociodemographic factors such as age, gender, education level and race/ethnicity may only be confounding factors associated with dietary patterns rather than independent determinants of plasma ENL concentration. The findings of this literature review complement those of earlier studies, and should be taken into account when considering interpersonal variability of lignans in humans.