How Your Gut Controls Your Hormones, Mood, Immunity & More
Last week one of our clients shared that she’s seen about 10 different GI doctors who all had the same message: “It doesn’t matter what you eat”.
Unfortunately, this is still the mainstream narrative for so many digestive issues—from colitis and Crohn’s to bloating, constipation, and diarrhea. Not only is this outdated but it is straight up wrong.
And it extends far beyond digestive symptoms. Here’s the truth: your gut microbiome influences every system in your body. From your hormones and immune function to your energy, mood, and even joint pain, your gut plays a foundational role in your health. And what you eat is one of the most powerful drivers of your overall gut health.
I was amazed by a recent meta-analysis showing that participants with knee osteoarthritis who took a probiotic experienced less pain, symptom severity and lower levels of inflammation (hs-CRP).
Not because I believe that simply taking a probiotic is the solution but because it highlights how connected the microbiome is to all areas of health, not just digestion.
The meta-analysis compiled data from five randomized controlled trials that included 694 participants with knee osteoarthritis and found that taking probiotics with various bacterial strains reduced pain and symptom severity compared to a placebo with large effect sizes.
The researchers noted that recent advances in microbiome research have illuminated the crucial role of the gut microbiome in arthritic conditions. They stated that disruptions in the gut microbiota can trigger joint inflammation.
After more than a decade of seeing this exact connection play out with our clients, from joint inflammation to other manifestations of inflammation, it’s exciting to see these patterns between gut health and inflammation increasingly reflected in the scientific literature.
The Gut Microbiome is The Epicenter of Health
Your gut is home to over 100 trillion microbes, that’s more bacterial cells than human cells in your entire body! And these microbes aren’t just passive passengers, they’re chemical factories. They eat what you eat, and in return, they create powerful compounds that directly impact everything from:
+Mood and mental health
+Metabolism and weight
+Hormone balance
+Immune system and inflammation
+Skin health
+Metabolic health (blood sugar, cholesterol, etc.)
+Energy and sleep
In other words, your microbiome is central to just about every outcome you care about.
What You Eat Actually Does Matter
When I lecture to physicians or my graduate students studying to become doctors and dietitians, I always say:
Now that we know more about the gut microbiome, it’s undeniable that nutrition plays a critical role in every single disease and how you feel day to day.
One study found that dietary shifts can alter your microbial communities in just 2-3 days. That means what you eat this week can literally shift your biology next week. And yet, most conventional doctors are still saying food doesn’t matter.
4 Core Nutrition Principles for Gut Health
If you’re struggling with bloating, constipation, diarrhea, IBS, IBD, SIBO, metabolic issues, or just want to feel better in your body, these four principles are essential.
1. Eat at Least 30 Grams of Fiber a Day
Fiber is one of the most science-backed nutrients for supporting overall health and reducing risk of nearly every disease. And very few people get enough of it. This is why our weekly meal plans in The Being Collective focus on 30-40g of fiber per day.
This is especially true for soluble fiber, which has two different forms: one type of soluble fiber helps form a gel substance that binds to cholesterol and toxins to help with excretion. The other type of soluble fiber is prebiotic fiber. The good bacteria in your large intestine eat the prebiotics which is when fermentation occurs and leads to the creation of short chain fatty acids. This is incredible for your body because short chain fatty acids impact so many functions, some of which include:
1-Healing your gut lining
2-Regulating blood sugar
3-Improving energy and sleep
4-Supporting hormone production like estrogen
5-Reducing inflammation throughout the body
Note: If fiber causes a lot of digestive discomfort, don’t give up and don’t buy into the need to follow a low FODMAP diet for life–this is in fact harmful to the gut long-term. Start building up fiber intake slowly. Try cooking vegetables, peeling vegetables and blending into smoothies. And don’t forget to drink plenty of water to help fiber move smoothly through your system. If that still doesn’t work, my team of Dietitians and I would love to work with you and help you get deeper into the root cause. The solution is not just removing fiber for the rest of your life as this is a critical element to long-term gut health.
2-Focus on Diversity
The healthiest microbiomes aren’t just housing a lot of bacteria, they’re filled with diverse bacteria. And the best way to support diversity is by eating a wide range of plant-based foods instead of eating the same meals day after day and week after week. This is a huge aspect of The Being Collective–generating weekly nutrition plans with diversity to take the guesswork out and support long-term consistency.
If you want to fuel a truly healthy, diverse and resilient gut microbiome, aim for a wide variety of fruits, vegetables, nuts, seeds, legumes, and whole grains. Each plant offers different types of fibers but also different polyphenols that feed different microbial species.
More diversity in your diet = more diversity in your gut = better overall health.
3-Everyone’s Microbiome is Unique
Everyone’s microbiome is different. While genetics set the stage, your daily choices like what you eat, your stress levels, and even how much time you spend in nature, shape your ecosystem.
That’s why personalized nutrition is essential. A brand new meta-analysis that looked at 28 randomized control trials assessed what the most effective diet was for improving Irritable Bowel Syndrome (IBS). It showed that the most evidence exists for low FODMAP diets but that there are a lot of other promising approaches that were effective for some including: gluten-free, starch restricted diets, personalized diets, and low carbohydrate diets. The personalized diet that was tailored to individual tolerances and preferences improved the participants IBS symptoms by 46%.
A big takeaway: What helps one person with their bowel movements may cause diarrhea or constipation for someone else. For some people the issue is underlying gut inflammation, lack of production of short chain fatty acids, bacterial overgrowth in the large intestine, small intestinal bacterial overgrowth, and more. This is where testing and working with a functional medicine Registered Dietitian can make a huge difference!
4-Think of your Gut Like a Rainforest
The gut microbiome is like an ecosystem or a rainforest. All of these microbes regulate one another and feed one another. Adding a single strain of bacteria via a probiotic? That’s like planting one tree in a forest. Sometimes it truly can be helpful but it can’t be the only solution. We want to change the entire ecosystem. This is where nutrition, prebiotics, stress reduction and other lifestyle practices can come into play.
But this is also why I have been so excited by the prospect of fecal transplants continuing to become a therapeutic option for some people in the future. This is when you transfer an entire microbial ecosystem from one person to another. Preliminary research shows that this can lead to dramatic results in conditions like C. diff, Multiple Sclerosis, Irritable Bowel Syndrome, and Parkinson’s–though they’re not yet FDA-approved beyond resistant C. diff.
The point is: it’s not about one thing. It’s about the whole system. That’s why a holistic, food-as-medicine approach that factors in your personal nutrition needs, supplement needs, stress levels, and more will always work best.
The Bottom Line
Food is not neutral. It’s information. Every bite you take sends messages to your microbiome, and in turn, your microbiome sends messages to every other system in your body. Your gut:
- Produces neurotransmitters like serotonin
- Supports estrogen metabolism through the estrobolome
- Influences hunger hormones like leptin and ghrelin
- Impacts detox pathways in the liver
- Helps regulate inflammation and immunity
Healing is very rarely linear but one thing is absolutely consistently true: the health of your gut microbiome is absolutely the foundation of your overall health.