Biobeschikbaarheid van enterolignans en hun relatie met chronische ziekten = Bioavailability of enterolignans and their relation with chronic diseases

Keywords:Lignans; enterodiol; enterolactone; plasma; flaxseed;bioavailability; liquid chromatography; mass spectrometry; case-control studies; prospective studies; colorectal adenomas; colorectal carcinomas; coronary heart diseasesLignans are biphenolic compounds that occur in foods of plant origin. Some of the plant lignans can be converted into the enterolignans, enterodiol and enterolactone, by the microorganisms in the colon. Because of their biological activities, enterolignans may affect the development of chronic diseases. It is not sufficiently known to what extent enterolignans become bioavailable, i.e., are absorbed and used for metabolic processes in the body.The aim of the present research was to gain further insight in the bioavailability of enterolignans and in their relation with several chronic diseases. To be able to do this, we developed a liquid chromatography-tandem mass spectrometry method using triply 13 C-labeled isotopes for the simultaneous quantification of enterodiol and enterolactone in plasma.Enterodiol and enterolactone absorption started 8 to 10 hours after consumption of secoisolariciresinol diglucoside, an isolated plant lignan, and they were eliminated slowly. A substantial part (~40%) of the enterolignans was excreted in urine, and thus had been available in the blood circulation. Because of the slow elimination, enterolignans will accumulate and reach steady state concentrations in plasma when consumed 2 to 3 times a day. As lignans are present in many foods this is very likely to happen. The bioavailability of lignans from flaxseeds, a high lignan source, improved substantially when whole seeds were replaced by crushed or ground seeds. Independent determinants of plasma concentrations of enterolignans were, besides the intake of plant lignans, use of antibiotic therapy, defecation frequency, and body mass index.Our data suggest a protective role of enterolignans against colorectal adenomas; the risk reduction was ~2-fold in highest versus lowest quartile of enterolignan plasma concentrations. However, a protective effect could not be confirmed for colorectal carcinomas. Moreover, we observed increased risks (~2.5-fold) in women, especially in postmenopausal women, and in subjects with a high body mass index. This suggests that an estrogen-related hormonal mechanism might be involved. In addition, our data do not support a protective role of enterolignans against the development of nonfatal myocardial infarction.In conclusion, a substantial part of the enterolignans enters the blood circulation and is subsequently excreted in urine. Enterolignans might protect against colorectal adenomas. We did not find protective associations for colorectal carcinomas and myocardial infarction. At this point, there is not enough evidence to give recommendations regarding the consumption of foods rich in lignans.

Bibliographic Details

Main Author:	Kuijsten, A.
Other Authors:	van 't Veer, Pieter
Format:	Doctoral thesis biblioteca
Language:	Dutch
Subjects:	adenoma, bioavailability, colorectal cancer, disease prevention, heart diseases, lignans, linseed, adenoom, biologische beschikbaarheid, colorectaal kanker, hartziekten, lignanen, lijnzaad, ziektepreventie,
Online Access:	https://research.wur.nl/en/publications/biobeschikbaarheid-van-enterolignans-en-hun-relatie-met-chronisch
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