Are Probiotics The Key To Hormonal Health?

Things we loved in the 1990s: the Spice Girls, chokers, Impulse body spray and probiotics. Fast forward a few decades, and the latter still has pride of place in the kitchen cabinets of the nutritionally minded public. In fact, since new research appeared mid-pandemic linking a healthy gut with less severe cases of COVID, sales of probiotic supplements have surged once again, putting the global market on a trajectory of being valued at $125 billion by 2027. 

But with the latest research lasering in on how the microbiome interacts with hormones – the MVPs when it comes to decoding women’s wellbeing – gut health, and the ability of probiotics to influence it, is set to hit scientific superstar status. So how close are we really to unlocking probiotics’ potential when it comes to our hormones?

Inside job

Recognised as an organ in its own right, the gut is populated by trillions of bacteria in the gastrointestinal tract; bacteria thatare crucial to your physiology, says women’s health specialist Dr Ghazala Aziz-Scott. Known as your microbiome, these bacteria influence everything from mood to immunity, sleep to ageing, cancer to allergies. The list is endless and growing. As Professor Tim Spector, a world-leading expert, puts it: “The ability to manipulate the gut microbiome therapeutically is absolutely massive. It should be the centre of medical attention for the next decade.”

But, how do we access that potential? Experts agree that eating a wide variety of plant-based foods, alongside a regular smattering of fermented foods and drinks, is key to achieving a wide diversity of species, along with an ideal ratio of good-to-bad microbes.

But targeting the treatment is trickier. “The first step in microbiology is to identify a bug,” explains Spector. “The second is to assign it some function and work out what it eats and what chemicals it produces; and then to investigate whether it’s commonly found in people who are sick or healthy.” But when it comes to female health? Things get a bit more complicated.

Under the Influence

Chances are you’re already familiar with the gut-brain axis – the bidirectional communication between centres of the brain and the gut. “Neurotransmitters, such as serotonin and dopamine – which affect mood and behaviour – are produced by bacteria in the gut,” says Professor Ina Schuppe Koistinen, director of the department of microbiology, tumour and cell biology at Sweden’s Karolinska Institute. But recent research has also revealed there are “conversations” taking place between the gut and the reproductive and endocrine systems. In fact, such is the gut microbiota’s (GM) influence – interacting with oestrogen, androgens, insulin and other hormones – that
it’s considered an “endocrine organ”.

Gut health expert Dr Megan Rossi (theguthealthdoctor.com) explains, “Your gut microbiome is able to influence circulating oestrogen levels thanks to an enzyme it produces called beta-glucuronidase. This can turn inactive oestrogen into active oestrogen, recycling it from your gut back into your circulation.” As a result, GM dysbiosis – impaired diversity and/or function of the intestinal microflora – has been shown to negatively impact circulating oestrogen levels. “This can play a role in common hormonal conditions, ranging from polycystic ovary syndrome (PCOS) and endometriosis to infertility,” she says.

Gut Feeling

Drill down into specific health conditions and the plot thickens. Take PCOS, for example. Research has shown that women with it have markedly more of the microbe B. vulgatus. When mice were given a faecal transplant of this from a woman with PCOS, they soon developed PCOS-like symptoms. Meanwhile, patients with PCOS also saw
a decrease in levels of serotonin and appetite-regulating hormones ghrelin and PYY, suggesting the brain-gut axis is involved in the condition. 

Endometriosis – a condition in which some womb lining-like tissue grows in places other than the womb, such as the fallopian tubes – is also linked with the gut. “We now know endometriosis is a complex process involving oestrogen dominance, autoimmunity and inflammation – all of which are influenced by the gut microbiome,” says Aziz-Scott. It follows, then, that the severity of the condition can be improved by enhancing the microbiome. Some studies have found an elevated ratio of certain bacteria in endometriosis sufferers – a finding which indicates that “there may be a direct link between the changes in the gut microbiota and the onset and progression of endometriosis”, Aziz-Scott adds.

What’s more, the gut microbiome’s influence on oestrogen could also make it a key player in managing menopause. Research has shown that soy isoflavone supplementation in postmenopausal women increases Bifidobacterium concentration (which is beneficial to immunity) and suppresses Clostridiaceae (known to be involved in inflammatory diseases). “In postmenopausal women, oestrogen deficiency reduces some bacterial species that impact T-cells, which are part of our immune response,” says Aziz-Scott. “We also know the GM can have an impact on the risk of osteoporosis.”

Prescriptive Approach

Such research makes for some fascinating reading. But while the prospect of actually pinpointing a bacteria ‘formula’ for limiting a hormonal fallout sounds promising, we’re not quite there yet. Rossi points out that most of the research to date has been conducted on animals, as well as being observational in nature, meaning you can’t prove the causation. “[The existing research] is simply showing a link between gut bacteria and disregulation of hormones,” she says. “In the future, we may be more prescriptive based on the type of hormonal disregulation. But at the moment we don’t have that level of detail – despite a lot of the microbiome testing companies telling us otherwise.” The message? While the future’s looking bright for personalised probiotics, it’s still a ‘coming soon’ trend.

So if we’re not there yet, where are we? “Lactobacillus rhamnosus, lactobacillus acidophilus and lactobacillus brevis are thought to improve the vaginal microbiome and prevent both thrush and bacterial vaginosis,” explains Aziz-Scott. Meanwhile, Bifidobacterium strains are thought to be beneficial in reducing intestinal inflammation, while Saccharomyces boulardii is a yeast that ‘acts’ as a probiotic by crowding out the less beneficial bacteria and encouraging the population of the good ones. 

That said, every expert we spoke to for this piece emphasised that scanning labels for specific strains isn’t the way forward; they’d much rather you focused on your diet more generally. “It’s important to promote gut health naturally with a diet that is anti-inflammatory, low in sugar and alcohol and includes a wide variety of fruit and vegetables, along with phytonutrients and probiotic foods,” says Aziz-Scott. Similarly, Schuppe Koistinen recommends taking the same approach to female health as we do for mood disorders; one centred around influencing the microbiome. “Patients with a vulnerability
to depression should be encouraged to enhance a plant-based diet with a high content of grains, fibres, fermented foods and fish,” she says. “The same is valid for issues with endocrine pathways and hormones.”

Need help filling your basket? Foods that have probiotic (aka ‘live’) bacteria in them include live yoghurt, sauerkraut, kefir, kimchi and kombucha. Prebiotic foods, on the other hand, provide the soluble fibre that gut bacteria need to help keep the lining of the intestine healthy – these include fibrous fruits and vegetables, such as onions, garlic, asparagus and artichokes. While the quantity of viable bacteria in a probiotic supplement can vary, prebiotic foods are a fail-safe way of supplying fermentable fibre to your own beneficial gut bacteria – a factor that has the greatest influence on microbial diversity in the gut.

What the supp

Got your diet licked? Good. Because there’s still a case for supplementing a healthy, balanced diet with probiotics. “Pick live probiotics that are ideally kept in the fridge and contain over five billion colony-forming units – and ideally multiple microbes,” tips Spector. Aziz-Scott recommends prioritising those with multiple beneficial bacterial species (“these usually include lactobacillus, Bifidobacterium and Saccharomyces boulardii”). “It needs to be stable in stomach acid so it doesn’t prematurely dissolve and can release its contents into the small intestine,” she adds. “Use professional brands – check it has no dairy, no binders or fillers, and check the expiry date.” 

The science is evolving at pace, and a bespoke probiotic future is looking bright. But until we have the science to select the right probiotics to suit your individual needs, try going back to basics. When it comes to gut health, it’s about the nutritional package. Be consistent; focus on a variety of plant-based and fermented foods; support your microbiome with prebiotics; and avoid overdoing it on sugar and alcohol. And while we watch and wait, supps could have a role to play. The 1990s have made a comeback – and it looks like probiotics are here to stay.