Background: Lignans in plant foods are metabolized by gut bacteria to the enterolignans, enterodiol (END) and enterolactone (ENL). Enterolignans have biologic activities important to the prevention of cancer and chronic diseases. We examined the composition of the gut microbial community (GMC) as a contributor to human enterolignan exposure.
Methods: We evaluated the association between the GMC in stool, urinary enterolignan excretion, and diet from a 3-day food record in 115 premenopausal (ages 40-45 years) women in the United States. Urinary enterolignans were measured using gas chromatography-mass spectroscopy. The GMC was evaluated using 454 pyrosequencing of the 16S rRNA gene. Sequences were aligned in SILVA (www.arb-silva.de). Operational taxonomic units were identified at 97% sequence similarity. Taxonomic classification was performed and alpha and beta diversity in relationship to ENL production were assessed. Multivariate analysis and regression were used to model the association between enterolignan excretion and the GMC. Bacteria associated with ENL production were identified using univariate analysis and ridge regression.
Results: After adjusting for dietary fiber intake and adiposity, we found a significant positive association between ENL excretion and either the GMC (P = 0.0007), or the diversity of the GMC (P = 0.01). The GMC associated with high ENL production was distinct (UNIFRAC, P < 0.003, MRPP) and enriched in Moryella spp., Acetanaerobacterium spp., Fastidiosipila spp., and Streptobacillus spp.
Conclusion: Diversity and composition of the GMC are associated with increased human exposure to enterolignans.
Impact: Differences in gut microbial diversity and composition explain variation in gut metabolic processes that affect environmental exposures and influence human health. Cancer Epidemiol Biomarkers Prev; 24(3); 546-54. ©2014 AACR.
©2014 American Association for Cancer Research.