Understanding the Connection Between Gut Health and Hormones

I love talking about the digestive system - it’s a powerhouse for the rest of the body! Without it, we’d have an awful time trying to build and repair tissues, and even have energy for thinking. I would be strongly suspicious of anyone who doesn’t have at least a little bit of interest in how the digestive system works.

A fascinating and often overlooked connection that I talk about in my one-on-one nutrition counseling sessions is the relationship between gut health and our hormones. This connection is a dynamic link influencing everything from mood and metabolism to energy levels and immune function. Taking care of your gut can lead to better hormone function!

At the heart of the gut-hormone connection is the gut microbiome - this is a complex ecosystem of bacteria, fungi, viruses, and other microorganisms that live in our digestive tract. Everybody’s microbiome is unique, like a fingerprint! These good gut bugs have important jobs in maintaining overall health and are involved in not only digestion, but brain activity, neurotransmitter production and even the pain response.

Gut bacteria have receptors that are involved in the production of hormones, and have a role in the metabolism of hormones - when we are done using hormones in the body, we have to have a way to clear their by-products, which is where the digestive system can be so important. This means that the state of our gut can directly impact our hormones. Now, don’t let anyone tell you that your gut is the “root cause” of your hormone problems or that “healing your gut” will cure your hormone-related conditions, but do know this - how you care for your digestive system can be a pivotal part of your whole-person hormone health routine.

One of the primary ways the gut impacts hormone production is through the regulation of the gut-brain axis, a communication pathway between the digestive system and the brain. This axis works in managing our stress response, which in turn influences our hormone levels. When the brain reads stress or potential danger, it can change how the muscles of the gut move and can contribute to symptoms like diarrhea, bloating, constipation and abdominal pain. When we are relaxed, the gut can function normally and we generally have better tolerance for foods and fluids. Our gut is also where we produce serotonin, a neurotransmitter involved in mood regulation - about 80% of its production happens in the gut! Digestive muscles that are regularly under lots of stress can alter their motility, and an irritated gut may impact our bodies mood and response to cortisol, our stress hormone, and insulin, the hormone that lowers blood sugar.

When the gut microbiome becomes imbalanced (meaning, too much “bad” bacteria and not enough “good”), it can lead to a condition known as dysbiosis. It’s important to know that we don’t have definite amounts of the different strains of bacteria that we are each supposed to have - the research in this area is still growing! This is often popularized on social media, usually to sell you some stool test or supplement or cleanse or program, none of which you actually need to take care of your gut. Imbalances of the gut microbiome can be related to a nutrient-poor diet, especially low fibre intake, high stress and poor sleep, and long-term overuse of antibiotics. As a preface, we like antibiotics when they are used correctly, including for conditions like Small Intestine Bacterial Overgrowth (SIBO) and other bacterial infections - what we don’t like is antibiotics given as a band-aid (I see this often in the case of suspected urinary tract infections, where nobody actually tests the urine and they are given antibiotics automatically).

The gut plays a crucial role in metabolizing estrogen, a key reproductive hormone. When the gut isn’t working well, estrogen can function at a higher level and stimulate the tissues to a greater extent (this is not called estrogen dominance, by the way - that’s not a thing), leading to changes in menstrual cycles, increases in breast or chest tenderness around a cycle and heavy menstrual bleeding.

The gut microbiome has also been shown to influence thyroid hormone levels. A digestive system that is poorly managed may contribute over time to changes in thyroid function, which impacts symptoms like fatigue, bowel movement alterations and mood changes. Folks who experience low or high thyroid function can benefit from supporting their gut health - not restricting food from the digestive system.

The gut also heavily influences leptin and ghrelin, hormones involved in appetite regulation. Leptin signals fullness, while ghrelin signals hunger. If our digestive system isn’t getting enough stimulation, there is low microbial diversity or there is limited fibre intake to feed the gut bugs, the balance and function of these hormones is disrupted, leading to lots of food cravings, poor hunger and fullness tone and even the term “food noise”.

The good news is that maintaining a healthy gut microbiome can help support better hormone function, and doesn’t require restriction or weird food changes. A diet rich in fruits, vegetables, whole grains, and legumes helps promote a healthy microbiome by providing fiber and prebiotics that nourish beneficial gut bacteria. Fermented foods like yogurt, kimchi, sauerkraut, and kefir are rich in probiotics, which are beneficial bacteria that support gut health - they don’t build up in the gut, but they can influence the types of bacteria that the body can produce on its own and continue to provide beneficial effects.

There’s some thought that high sugar and processed foods can harm the gut microbiome and promote the growth of harmful bacteria, but I like to consider this in context: is sugar intake preventing other nutrient dense foods from being consumed? Are processed foods common for the person, or not (and what kind of processed foods? Processed is an umbrella term). And is the consumption of these foods related to negative symptoms, or not?

Chronic stress can wreak havoc on both gut health and hormone balance. Incorporating stress-management techniques and routines can be beneficial, like turning off your phone before bed, including time to decompress after work, and practicing mindfulness. Good quality sleep is also essential for both gut health and healthy hormones. Aim for 7-9 hours of restful sleep each night to support optimal hormone function - there can be unique variations, so talk to your doctor if you’re not sure.

Sometimes probiotic supplements can be helpful, but not all probiotics are the same and every strain does something a little different. Talk to a dietitian to find one that meets your needs, and learn how to check labels for third party tested products (we have some strong rules in Canada around supplements, so this helps to protect consumers!).

The connection between gut health and hormones is a complex but crucial one. A balanced gut microbiome is essential for maintaining hormonal equilibrium, while an imbalanced gut can disrupt hormone production and regulation, leading to a variety of health issues. By nourishing your gut through food, managing stress, and prioritizing good sleep, you can support both your gut and hormonal health, leading to better overall well-being. Remember, taking care of your gut is not just about digestion—it’s an investment in your entire body's function, including your hormones!