The Digestive Microbiota Influences Oestrogen Associated Diseases
Factors like genetics, liver metabolism efficacy, monthly fluctuation of hormones, health status, exogenous impacts such as diet, chemical exposure and pharmaceuticals can all change how oestrogen is metabolised and excreted and thus influence circulating oestrogen levels. Gastrointestinal (GI) microbes have been identified that influence both risk and protection from oestrogen-associated disease states. This knowledge makes microbiome composition an important consideration in oestrogen-related health status.GI microbes have been identified that are capable of metabolising phytoestrogens such as isoflavones and lignans, converting them into protective metabolites with possible benefit in breast cancer. These include Coriobacteriaceae, such as Eggerthella lenta (lignin metabolism), and Slackia and Adlercreutzia genera which are equol producers.
Delivery via bile into the small intestine results in fibre binding in the intestine and subsequent exit via the rectum or reabsorption and entrance back into circulation (entero hepatic recycle).
Oestrogen-associated disease risk is linked to GI-based deconjugation and subsequent reabsorption of previously metabolised oestrogens. Prior to reabsorption, conjugated oestrogens are deconjugated via bacterial species possessing ß-glucuronidase and ß-glucosidase functionality. The expression of these two key deconjugation enzymes have been found to be linked to GI microbial diversity.
Kwa M, Plottel CS, Blaser MJ, et al. The intestinal microbiome and estrogen receptor-positive female breast cancer. J Nat Can Inst 2016;108(8), [Abstract]
Clavel T, Borrmann D, Braune A, et al. Occurrence and activity of human intestinal bacteria involved in the conversion of dietary lignans. Anaerobe 2006;12:140-147, [Abstract]
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