Read time: 9 minutes
Somewhere in the last few years, “gut health” stopped being about digestion and became a whole identity. It may be the most oversold and undersold topic of women’s health at the same time.
Oversold, because it has become the explanation for everything!
Bloated? Microbiome. Tired? Microbiome. Anxious, breaking out, not losing weight, not sleeping? There is a powder, a probiotic or a $90 bone broth subscription promising to fix it by “healing your gut”.
Undersold, because beneath the noise there is actually an important story that most women were never told.
Your gut bacteria help your circulating oestrogen.
They help train your immune system, produce compounds that support the gut lining and influence how some hormones are processed. And the way your microbiome ages may be one of the more interesting predictors of how you age.
So what will the $60 tub of probiotics, gut-healing powders, gut-reset protocols, gut-sealing collagen and "microbiome-supporting" everything actually do for you? The marketing pitch is pretty consistent: your gut is damaged, leaky, inflamed and out of balance, and this product will heal it. The message works because it can’t really be disproven at the checkout. You can’t see your microbiome. You can’t feel a probiotic colonising. So you’re left trusting the label.
Which is exactly why it’s worth asking: What does the microbiome actually do for women? Which of these products has decent human evidence behind it? And is your gut, in fact, broken?
Let’s investigate.
What actually is the Microbiome?
Your gut microbiome is the community of trillions of bacteria + viruses and fungi, living mostly in your large intestine. Collectively they carry far more genes than you do, and they do important metabolic work.
Three jobs matter most:
First, digestion and fuel: your bacteria ferment the fibre you can’t break down yourself, and in doing so they produce short-chain fatty acids like butyrate, the preferred fuel for the cells lining your colon. A gut that makes plenty of these tends to have a stronger, calmer barrier.
Second, immune signalling: most of your immune system sits around your gut, and the microbiome helps train it, which is part of why dietary fibre and the bacteria that ferment it are tied to gut-barrier integrity and lower inflammation.
Third, your gut bacteria help recycle some of your hormones. And this is the one that makes it a important women’s health topic.
That third job is where women stop being a footnote or classed as “smaller men” with a gut.
Why?
The microbiome is not sex-neutral because it is tangled up with your hormones.
Why should we care: The Estrobolome
Here is the part the generic gut-health content skips.
A specific set of your gut bacteria carries genes for an enzyme called β-glucuronidase, and this collection has its own name:
The estrobolome.
Its job is to influence how much oestrogen stays in your body.
The mechanism is more elegant than it sounds. Your liver packages up oestrogen for disposal by tagging it for excretion. Some of that tagged oestrogen is sent into the gut and when there, β-glucuronidase-producing bacteria snip the tag off, freeing the oestrogen to be reabsorbed back into circulation instead of leaving the body. In the estrogen–gut microbiome axis described in Maturitas, this is how the microbiome becomes a quiet regulator of circulating oestrogen.
The direction matters both ways.
A 2023 review on gut β-glucuronidase and female oestrogen metabolism describes how disruptions to the microbiome may alter the amount of oestrogen that is deconjugated and recirculated. Lower diversity has been linked with reduced oestrogen recycling, although researchers cannot yet predict a woman’s hormone levels from the composition of her microbiome.
Conversely, too much activity in the other direction is being studied for how it may raise lifetime oestrogen exposure, which is why the estrobolome is under investigation in oestrogen-sensitive conditions like breast cancer.
This isn’t only a theoretical, someday-in-midlife concern.
It’s being studied in women of reproductive age right now. Researchers have profiled the gut microbiome and estrobolome in reproductive-age women with endometriosis, and a separate study found higher β-glucuronidase activity in women with PCOS compared with controls. Both are oestrogen-linked conditions that show up during the reproductive years.
So the reason to care isn’t a powder promising a “reset.” It’s that your gut is wired into your hormonal system across your whole reproductive life.
Hold that thought, because this is exactly where the marketing tries to convert the science into a purchase.
The reality check: interesting is not the same as proven
Here is the move to watch for. A product points to a real mechanism: “the microbiome affects your hormones and immune system!” And then subtly implies that their capsule fixes it.
The gap between these claims is enormous.
Take probiotics, the flagship of the gut-healing aisle. The intuitive story is that you swallow beneficial bacteria and they move in and improve your microbiome. The evidence is far less flattering.
In a detailed study of probiotic colonisation in humans published in Cell, many healthy people were simply resistant to colonisation. The probiotic strains passed through without taking up residence in the gut lining, and the effect was highly personal.
Not one-size-fits-all.
It gets more deflating. A systematic review and meta-analysis in healthy adults found that supplementing a single-species probiotic did not meaningfully change the diversity or composition of an already-healthy gut microbiome.
That does not mean all probiotics are useless. Certain strains have evidence for particular symptoms or clinical situations. However, a generic capsule should not be assumed to permanently rebuild a healthy person’s microbiome.
The healthy gut, it turns out, is fairly stable and quite good at resisting outside invaders.
This is somewhat reassuring but also awkward for the supplement aisle.
Here is the crux of the whole “healing your gut” pitch:
It implies your gut is damaged and their amazing product repairs it. But in a healthy woman, the microbiome usually isn’t broken, and there’s little evidence that a generic probiotic rebuilds it. “Leaky gut” as a consumer diagnosis is far vaguer than the packaging suggests. Promising mechanisms are being sold as finished cures.
Which brings us to the product that best captures the whole phenomenon.
The bone broth investigation
Bone broth is the perfect case study, because it sits exactly on the line between “nourishing food” and “medical claim.”
What’s actually in it? Bone broth is bones and connective tissue simmered for hours. It contains gelatin, collagen and amino acids like glycine and proline + some minerals.
Those aren’t fake.
Glycine and proline are real building blocks, and warm, protein-containing broth is a perfectly nice thing to consume… So far, so good.
What’s been tested? Here’s the problem: direct human trials on bone broth itself healing the gut are essentially non-existent. Most of what gets cited is lab-dish or animal work, which can’t be assumed to apply to a person’s digestion.
The closest human evidence comes from collagen peptides, a related but standardised ingredient, and even that evidence is thin. A 2022 study of healthy women taking 20g of collagen peptides daily reported reduced bloating and milder digestive symptoms, but it had no placebo group and only 14 of 40 women finished it. That’s a hypothesis worth exploring, not proof of “gut healing.”
What hasn’t been tested and what has? Beyond the missing efficacy trials, there’s a wrinkle the marketing never mentions.
Bone broth is not a standardised product. Its amino-acid and mineral content varies according to the bones used, acidity and cooking time. Studies have detected small quantities of undesirable metals alongside the desirable minerals, although the available analyses have not established a meaningful health risk from normal consumption. What they do show is that one pot of bone broth cannot be assumed to deliver the same nutritional dose as another..
The honest verdict on bone broth: a nourishing food filled with amino acids, and essentially no human evidence that it “heals” the gut.
The biology of glycine is concrete. The gut-healing marketing is spongey at best.
What actually has human evidence
If powders and the bone broth are full steam ahead of the science, what’s actually behind it?
The answer is obviously unglamorous, which is probably why nobody’s building a subscription box around it.
Fibre and plant variety.
One of the most reliable ways to support the microbiome is to feed the bacteria already living there.
Fibre is what they ferment into the short-chain fatty acids that fuel and strengthen the gut barrier, which is why fibre consistently comes out on top for barrier integrity and lower inflammation. Variety matters as much as volume. Different plants feed different bacteria.
Some fermented foods. This is the one traditional “gut” food that earns its reputation. In a Stanford trial comparing a high-fibre diet with a fermented-food diet, the fermented-food group ( think yoghurt, kefir, kimchi, kombucha, fermented vegetables) increased their microbial diversity and lowered markers of immune inflammation over ten weeks.
Real food, measurably moving the immune system, in healthy adults.
Notice what these have in common. They’re foods, not products. They work by feeding and diversifying the community you already have, slowly, rather than promising to install a new one.
The microbiome is a garden, not a switch. You tend it with what’s on your plate… not with one expensive jar.
The Claritti verdict
Here’s the reframe worth leaving with: for most women, the gut isn’t broken and doesn’t need “healing.” It needs feeding.
The marketing appears to be backwards. It sells the idea of a damaged, leaky, out-of-balance gut so it can sell you the repair. A probiotic that mostly passes through, a broth that hasn’t been shown to do what it claims, a powder standing in for a plate of vegetables. The science, the actual part that makes this a women’s health topic, is quieter but much more interesting. Your gut bacteria help recycle your oestrogen, train your immune system and fuel your gut lining, across your whole reproductive life.
Bone broth can absolutely be part of a good diet. It’s nourishing, comforting and contains valuable amino acids. It just hasn’t earned the word “heal.”
A probiotic might help in specific situations, but it’s not a reset button for a healthy gut.
The most useful thing you can do for your microbiome is also the least profitable to sell: eat a wide range of plants, get enough fibre, add some fermented foods you actually enjoy, and stop treating your gut like it’s an emergency.
Because it probably isn’t. Your gut is not broken.
Next up
In the practical guide, I’ll turn this into something you can actually do:
how to eat for diversity without it becoming a full-time job
which fermented foods are worth it (and which are not)
whether a probiotic is ever worth your money
how much fibre actually matters
The real question was never whether the microbiome matters. It’s what’s actually worth your time, money and energy.
Until then,
Curiosity is useful. Confusion is expensive. And clarity is the point.