Playing with hormones: How microorganisms control sex hormones
The microbiome, the complex community of trillions of bacteria and viruses, plays a crucial role in many aspects of our health – from digestion and the immune system to brain function.
The microbiome is also closely linked to sex hormones and may therefore have a decisive influence on the development of diseases such as ovarian cancer, osteoporosis and polycystic ovary syndrome.
The fascinating connection between the microbiome and hormones
Research shows that there is a bidirectional relationship between the gut microbiome and our sex hormones. This means that not only do hormones influence the composition of the microbiome, but that the microbiome itself also actively regulates hormone levels in the body. This interaction is a remarkable example of how profound the connection between microorganisms and humans is.
For example, it has been observed that the microbiome is composed differently in men and women. Studies in mice and humans have shown that testosterone, oestrogen and progesterone – the main sex hormones – can influence the diversity and composition of gut bacteria. Higher levels of certain bacterial families such as Bacteroidaceae have been found in men, while other bacterial groups dominate in women. This gender-specific composition is of enormous importance as it could explain why certain diseases occur at different rates in men and women.
The female microbiome
In the following, the focus will be on the female microbiome and its correlation to hormonal diseases in women and how health can be taken into one’s own hands.
Women and osteoporosis
One example of a hormone-related disease is postmenopausal osteoporosis. This form of bone loss, which occurs in women after the menopause, is triggered by a drop in oestrogen levels.
Oestrogen plays an important role in bone metabolism by inhibiting bone resorption and promoting bone formation. As oestrogen levels fall, the activity of osteoclasts, which break down bone, increases, while the activity of osteoblasts, which build bone, decreases. This leads to an imbalance in which more bone is broken down than is formed, which reduces bone density and increases the risk of fractures.
Interestingly, the gut microbiome appears to play a central role in this process. Experiments on mice have shown that a disturbed microbiota increases bone loss.
Certain bacteria can change inactive oestrogen in the gut via special enzymes (beta-glucuronidase) so that it can be reactivated and reabsorbed into the bloodstream.
Overall, the diversity and balance of the microbiome is important for optimal hormone regulation. If the microbiome is severely altered (dysbiosis), the intestinal barrier can also be disrupted and substances that trigger inflammation can enter the bloodstream. These inflammatory processes in turn ultimately lead to an increase in the activity of osteoclasts and thus to increased bone resorption.
A healthy and diverse microbiome can therefore stop or at least slow down bone loss. The intake of special probiotics could also open up completely new perspectives for the prevention and treatment of osteoporosis.
Women and polycystic ovary syndrome
Another exciting field is polycystic ovary syndrome (PCOS), a widespread hormonal disorder in women of childbearing age. Women with PCOS often suffer from irregular menstrual cycles, obesity and increased production of androgens, the male sex hormones. Current research suggests that women with PCOS have a much less diverse gut microbiome than healthy women. Impaired gut flora could therefore contribute to the insulin resistance and increased androgen levels that characterise PCOS.
A healthy microbiome can also help here and alleviate the symptoms of PCOS.
Women and ovarian cancer
Probably one of the most surprising findings is the possible link between the gut microbiome and ovarian cancer. Ovarian cancer is one of the deadliest gynaecological cancers and the exact causes are not yet fully understood. However, there is evidence that the microbiome may play a role in the development and progression of this disease. Bacteria can lead to an excessive increase in oestrogens and thus promote the growth of ovarian tumours. As described above, this occurs via the reactivation of inactive oestrogen.
This clearly shows that only a good balance of oestrogen is healthy for the body. While too much oestrogen can promote ovarian tumours, too little oestrogen in turn causes osteoporosis. This in turn requires a good balance in the microbiome.
There are also indications that the gut microbiome could influence the effectiveness of chemotherapeutic agents such as cyclophosphamide. In mice, a disturbed gut flora resulted in the treatment being less effective. This suggests that a healthy gut flora could not only help to prevent cancer, but also to improve its treatment.
We have it in our own hands
Although the focus here is on the female microbiome, this also applies equally to men. The findings on the connection between the gut microbiome and the sex hormones open up exciting new possibilities in medicine, but also in self-responsible prevention. Understanding these complex interactions could, in principle, lead to the development of future therapies aimed at modulating the microbiome in order to correct hormonal imbalances and treat sex hormone-dependent diseases.
However, it is also very clear – and this is the really good news – that investing in your own microbiome, in the form of sufficient exercise, a healthy diet and stress-reducing activities, definitely pays off. Diseases can be combated or even avoided altogether.
Everyone can break out of their passive role and instead actively and successfully look after their health. (JS)
_________________________________________________
Further reading / sources:
He S, Li H, Yu Z, Zhang F, Liang S, Liu H, Chen H and Lü M (2021) The Gut Microbiome and Sex Hormone-
Related Diseases. Front. Microbiol. 12:711137.
https://doi.org/10.3389/fmicb.2021.711137
Image material:
Header: © markin; www.depositphotos.com; Text: © katerynakon – www.depositphotos.com
