How your gut bacteria affect oestrogen

Your gut bacteria and oestrogen have much more to do with one another than you might think. Your gut bacteria actually regulate oestrogen metabolism, by producing enzymes that cause a cascade of reactions. The key event in the gut is what’s known as the deconjugation of oestrogen, meaning the splitting apart of bonds, turning oestrogen from its inactive form into its active form.

We need hormones in both states of active and inactive, depending on what their task is. Once our oestrogen is free to do its thing, it is sent to the bloodstream where it is then distributed throughout the body to get to its receptors. If you aren’t deconjugating oestrogen properly, you end up with far less oestrogen circulating through your body than you should have. This can lead to low oestrogen symptoms.

The system of your gut bacteria turning oestrogen into a usable form is called the oestrobolome.

Why your bones need oestrogen

Oestrogen slows down a group of cells called osteoclasts, which break down bone. You need some bits of bone to be taken away and replaced, but if you don’t have enough oestrogen, osteoclasts are more active, thus breaking down bone at a faster rate than they should be. This leaves you with low bone density and strength.

The oral contraceptive pill is an example of a drug that results in you losing bone at a faster rate than you would normally.

Some studies have found that a few different strains of probiotic bacteria, in certain circumstances, can increase bone formation, decrease bone reabsorption, and change the microstructure of bones. These studies were performed on Bifidobacterium longum, Lactobacillus helveticus, and L. reuteri. 

Another study into breast health found that women who had a cancer-positive biopsy had far less diversity in their microbiome than the control group, and circulating oestrogen levels were not related to the composition of the microbiome, which led researchers to believe that the microbiome works independently of oestrogen.


Jessica Lloyd - Naturopathic Practitioner, BHSc(N)

Jessica Lloyd - Naturopathic Practitioner, BHSc(N)

Jessica is a degree-qualified naturopath (BHSc) specialising in vulvovaginal health and disease, based in Melbourne, Australia.

Jessica is the owner and lead naturopath of My Vagina, and is a member of the:

  • International Society for the Study of Vulvovaginal Disease (ISSVD)
  • International Society for the Study of Women's Sexual Health (ISSWSH)
  • National Vulvodynia Association (NVA) Australia
  • New Zealand Vulvovaginal Society (ANZVS)
  • Australian Traditional Medicine Society (ATMS)
Read more about Jessica and My Vagina's origin story.