July 20, 2026
Can Your Gut Microbiome Affect Your Hormones and Cancer Risk?
The short answer: Emerging research suggests it might.
The short answer: Emerging research suggests it might.
A recent review published in npj Biofilms and Microbiomes highlights the fascinating relationship between our gut bacteria and the endocrine (hormone) system.
Certain gut bacteria, known collectively as the estrobolome, produce enzymes such as β-glucuronidase that can reactivate oestrogen that was ready to be eliminated from the body. This allows some oestrogen to be reabsorbed, potentially increasing the body's exposure to active oestrogen.
Because prolonged oestrogen exposure is a recognised risk factor for hormone-sensitive cancers, including some breast and endometrial cancers, researchers are investigating whether the microbiome may influence cancer risk.
Interestingly, this is one area where functional medicine has been looking for some time. We routinely measure β-glucuronidase on comprehensive stool tests as one marker of how the gut may be influencing oestrogen metabolism.
A raised β-glucuronidase level is not a cancer test, nor does it mean someone will develop hormone-driven cancer. However, it may suggest increased oestrogen recycling and can provide valuable insight when interpreted alongside symptoms, hormone testing and the wider picture of gut health. It can also help guide personalised strategies to support healthy oestrogen clearance.
Scientists are now exploring whether probiotics, prebiotics and other microbiome-targeted therapies could improve hormone health or even influence responses to treatments such as tamoxifen. However, most of the current evidence comes from laboratory and observational studies, so more clinical trials are needed before these approaches become routine.
The take-home message? Your gut microbiome is far more than a digestive organ. It plays an important role in hormone metabolism, immune function and inflammation. While we can't yet say that optimising the microbiome will prevent hormone-driven cancers, this exciting area of research reinforces the importance of looking after gut health as part of a comprehensive approach to long-term hormonal wellbeing.
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