Contribution of linseed intake to urine and serum enterolignan levels in German females: A randomised controlled intervention trial

Linseeds are a rich source of lignans, secondary plant substances which are suggested to possess chemopreventive effects inter alia with regard to breast cancer. In a randomised controlled trial 40 German women were informed about “5-a-day” and encouraged to increase their dietary intake of fruit and vegetables. Moreover 19 participants were randomly assigned to an intervention group supplemented with ground linseeds (20 g/d) over a 2-month period. Before and after intervention, urine and blood samples were collected after an overnight fast. Analysis was by intention-to-treat and the outcome parameters of interest were enterolignan concentrations.After linseed supplementation, enterolignan concentrations (mean) measured as their glucuronides by a newly developed high performance liquid chromatography electrospray mass spectrometry (HPLC–ESI-MS) in serum (122 nmol/l) as well as in urine (72 μmol/l) showed a significant increase (P < 0.01) compared to pre-intervention values (47 nmol/l and 29 μmol/l). In the control group enterolignan levels were raised slightly but did not reach significance. Serum and urinary enterolignans of the whole collective showed a good pairwise correlation.