Hormones have a habit of getting the blame for almost everything. Poor sleep, changing weight, mood, skin, periods, hot flushes, brain fog - at some point in a woman's life, somebody will probably tell her, “It's your hormones.”
Sometimes, of course, they're right. But hormones don't operate in isolation, and one of the more interesting areas of women's health research is looking somewhere you might not immediately expect: the gut.
Scientists have even given part of this relationship a name - the estrobolome. If you've never heard of it, you're in good company. Put simply, the estrobolome describes the ability of certain microorganisms living in our gut to help process oestrogen. That means the trillions of microorganisms in our intestine may be involved not only in digestion, but in what happens to some of our hormones after the body has used them.
And that makes the relationship between women, hormones and gut health rather more interesting than simply reaching for a probiotic yoghurt.
Meet your estrobolome
Oestrogen doesn't simply circulate around the body indefinitely. Once it has done its job, some of it is processed by the liver and sent towards the intestine for elimination. This is where our gut microorganisms can become involved.
Some bacteria produce enzymes that are able to change these processed forms of oestrogen. In doing so, they may allow some oestrogen to be reabsorbed rather than leaving the body. The estrobolome is the name we give to this collection of microbial activity involved in oestrogen metabolism.
It doesn't mean that your gut bacteria “control your hormones”, and it certainly doesn't mean that we can manipulate one bacterial species and magically balance oestrogen. Women's hormones are influenced by age, ovarian function, genetics, body composition, diet, medication and many other factors. What the estrobolome does tell us is that the gut deserves a place in that conversation.
What happens as our hormones change?
This becomes particularly interesting during perimenopause and menopause.
As ovarian oestrogen production changes and eventually falls, women can experience changes throughout the body. We tend to think first about periods, hot flushes and night sweats, but oestrogen receptors are found in tissues far beyond the reproductive system. Bone, cardiovascular health, brain function, metabolism and the gastrointestinal tract are all part of the picture.
Researchers are now asking whether changing oestrogen levels alter the gut microbiome and, equally, whether microbial activity influences the way oestrogen is processed. We don't yet have all the answers. Recent research has challenged the idea that menopause simply causes the microbiome to become universally “worse”. Women are far too biologically individual for such a neat explanation. What is becoming more interesting is not simply which bacteria we have, but what those bacteria are doing, and that distinction matters when we think about supporting the gut.
Start with what you eat
There isn't an “estrobolome diet”, despite what a quick internet search might lead you to believe, and no single food is going to detox your hormones. There are, however, very good reasons to feed the gut well.
Vegetables, fruit, pulses, wholegrains, nuts, seeds, herbs and spices provide different fibres and plant compounds for our intestinal microorganisms to work with. Rather than becoming fixated on one fashionable food, think about variety across the week. A lentil soup, porridge with berries and seeds, chickpea curry, handful of nuts, apple, tray of roasted vegetables and slice of good wholegrain bread may look rather ordinary compared with the latest gut-health powder, but collectively they provide an impressive range of substrates for our microorganisms.
Fermented foods can also be part of that picture. Live yoghurt, kefir, miso, kimchi and other traditionally fermented foods introduce another range of microbial organisms and fermentation products into the diet. Food remains the foundation, but our growing understanding of microbial function has also opened the door to another way of supporting the relationship between the gut and the body. Rather than thinking only about adding live microorganisms through probiotics, we can now look at the components of microorganisms themselves through postbiotics.
So where do probiotics and postbiotics fit?
We have traditionally thought about gut supplements primarily in terms of probiotics - taking live microorganisms that have demonstrated a health benefit. Postbiotics take a different approach.
A postbiotic contains inactivated microorganisms and/or their components that have demonstrated a health benefit. Because the microorganisms don't need to arrive in the intestine alive, a postbiotic can provide a defined microbial preparation without relying on a live microorganism surviving manufacture, storage and its journey through the digestive system, before interacting with an intestinal ecosystem that will be different in every woman.
Modern microbiome research is also becoming increasingly interested in function. We want to understand how microbial cells and their components communicate with the body, and how those interactions relate to the intestinal barrier, immune system, inflammatory signalling and metabolism. These are areas with particular relevance across women's health, especially as our hormonal and metabolic environment changes throughout life.
Postbiotics are already being studied directly in women. Human trials have investigated specific preparations in areas including inflammatory and endocrine markers in midlife women, while research into other women's-health applications continues to develop. We can't yet say that taking a postbiotic will “balance your hormones” or predictably alter your estrobolome, and I would be wary of any supplement making that promise. What we can say is that postbiotics offer a different and increasingly researched way of interacting with the gut environment without relying upon live bacteria.
For women interested in supporting gut health as part of a wider approach to health and healthy ageing, that makes postbiotics worth knowing about and, where there is appropriate evidence behind the particular preparation, worth considering alongside good nutrition rather than instead of it.
Food or a supplement? It doesn't have to be one or the other
One of the things I dislike about nutrition is the tendency to turn everything into a competition. Food versus supplements. Probiotics versus postbiotics. Natural versus manufactured. Human biology isn't particularly interested in our marketing categories.
A varied diet can provide fibre, polyphenols and naturally occurring fermentation products while supporting the microorganisms already living within the gut. Fermented foods can add another dimension, while a well-researched postbiotic can provide a defined preparation that doesn't depend upon live microorganisms remaining viable. The important question is not, “Which one wins?” but what are you trying to achieve, and what evidence do we have for the approach you're considering?
For me, that is where supplementation belongs: not as a substitute for good nutrition, but as something we can consider alongside it.
Your hormones don't live in a bubble
Perhaps that is the most useful thing to take away from the developing science of the estrobolome. For years we have talked about women's hormones as though they belong almost exclusively to the ovaries and reproductive system. We now understand that the story is much broader. The liver processes hormones, the intestine receives them, microorganisms can transform them and some may find their way back into circulation.
Add food, immune function, metabolism and the intestinal barrier into that picture and women's hormonal health begins to look less like a collection of separate systems and more like the interconnected biology it has always been.
Postbiotics add another piece to that picture. They don't replace a varied diet, fermented foods or probiotics, nor should they be sold as a shortcut to “balanced hormones”. They do give us a way of using defined microbial preparations without relying on live organisms, and human research in women is beginning to explore where that may take us.
So the next time somebody tells you that your symptoms are “just your hormones”, it might be worth remembering that even your hormones don't work alone. Your gut has been there all along.
Kate Arnold, Nutrition Consultant to The Postbiotic Company
This article is for general information and educational purposes only and is not intended to replace individual medical or nutritional advice. Food supplements should not be used as a substitute for a varied, balanced diet and healthy lifestyle. If you have a medical condition, are taking medication, or have concerns about your hormonal health, please seek advice from an appropriate healthcare professional.
