The role of the human microbiome on body functions apart from gut health is currently the focus of much fascinating research. One such area is how the gut microbiome and oestrogen levels are linked. 

What is the gut microbiome?

Firstly, within the human gut (and other parts of the body including the vaginal tract and breast tissue) there are groups of different types of bugs (bacteria, fungi, protozoa and viruses).

Together they are called a ‘microbiome’.

Importantly, these bugs are not just along for the ride – they have jobs to do! Jobs that have a significant influence on many body processes including; those relating to digestive,  metabolic, immune, mental/emotional and hormonal functions/health.

Across the human population the groups of bacteria that make up the gut microbiome are somewhat similar. When you get down to different species or strains however, these can be very different from one person to another.

So why does that matter? 

Because the different types of bacteria perform different jobs, the ones in your gut will influence how effectively your body can digest, metabolise and/or process certain substances. 

Such as hormones like oestrogen. 

How is this related to oestrogen levels?

One of the jobs of some of these gut bacteria is the metabolism of oestrogen. Such bacteria together are called the ‘estrobolome’ = gut bacteria that process or metabolise oestrogens. This metabolism can have a significant impact on the oestrogen levels in your body.

There are two main types of oestrogen – oestrone (E1) and oestradiol (E2), which are parent oestrogens that can be converted by phase I liver metabolism to many oestrogen metabolites.

Oestrogen metabolites can then be further conjugated (meaning joined to something else) through phase II liver processes (glucuronidation or sulfonation reactions) and excreted into bile, urine or faeces.

In the gut, some of these conjugated oestrogens in bile can be deconjugated (or broken apart) by certain bacterial species with beta-glucuronidase and beta- glucosidase enzyme activity, and the free oestrogens can be reabsorbed.

Consequently, non-ovarian oestrogen levels, which are highly variable between individuals, can be significantly influenced by the composition of the our gut bugs.

Does this mean that the gut microbiome and oestrogen levels are linked?

Many women experience issues associated with oestrogen imbalance (i.e. too high or too low) such as:  irregular or absent periods, bloating, mood imbalances, breast pain, low libido, weight gain, low energy levels, sleep issues, PMS and urinary tract infections.

Just to name a few!

In conclusion, this is why along with other strategies addressing diet, liver and thyroid health, improving the health of the gut microbiome is a vital step to balancing your hormones. Moreover, resolving the health issues or symptoms such an imbalance was causing.