Interview with Dr. Megan Rossi, The Gut Health Doctor

Dr. Thais Aliabadi and Mary Alice Haney sit down with Dr. Megan Rossi to cut through the noise around gut health and translate the science into practical steps women can use today. Megan is a gut health scientist, registered dietitian, and clinician who studies nutrition-based therapies for the microbiome and women’s health. Below we present an interview-style deep dive that covers hormones, fiber, IBS, and SIBO, probiotics, fermented foods, lifestyle tools, and clear steps to strengthen your gut—no gimmicks, just evidence and doable habits.

Table of Contents

• Quick navigation
• FAQ
• Final practical checklist to start today

Quick navigation

• Hormones and why women experience more gut symptoms
• How to know when your gut needs attention
• Tests to rule out serious disease before trying diets
• IBS vs SIBO: differences, diagnosis, and treatment paths
• Fiber, fruit, and gut training—how to add plants without pain
• Low FODMAP: rest, reintroduce, personalize
• Plant diversity and fermented foods: the two pillars
• Probiotics vs fermented foods: when strains matter
• Supplements that make sense
• Microbiome testing: what you can and cannot learn
• Practical meal examples and three small habits you can start
• FAQ for fast answers

Why do women tend to have more digestive symptoms than men?

Women report more gut trouble—and it’s not imaginary. There are several overlapping reasons. First, sex hormones like estrogen and progesterone interact directly with receptors in the gut. Those hormones influence gut motility, absorption, and the sensitivity of the gut lining. That’s why many women notice changes in bloating or food sensitivity at different points in the menstrual cycle.

Second, women tend to have slower gastrointestinal transit times, which means food and residues spend more time in the gut. Slower transit can increase fermentation and gas production, which raises the chance of bloating and constipation.

Third, the gut-brain connection matters. Stress and multitasking activate the brain’s stress networks and send strong signals to the gut, often amplifying symptoms. In short, hormonal biology, motility differences, and psychosocial stressors all combine to make women more vulnerable to gut symptoms.

How do we know if our gut is healthy? Are symptoms the only signal?

Symptoms are only part of the picture. Historically, we equated the absence of bloating, constipation, or pain with “healthy,” but the gut microbiome research shows the gut affects every organ system—immune function, metabolic health, and mental health among them. So a quiet gut does not guarantee ideal gut biology.

Megan uses a simple 10-question assessment in the clinic to get a broader snapshot—digestive symptoms, stress levels, medication use, sleep quality, and restrictive diets all influence gut health. People who have low mood, frequent infections, or poor resilience may have underlying gut issues even if they aren’t bloated every day.

The practical takeaway: look at symptoms but also consider resilience (how quickly you recover from illness), mood and sleep, and medication history. Those inform whether to intervene and which levers to pull.

What should someone do first if they have persistent digestive symptoms?

Start by ruling out red flags. Get testing for celiac disease and inflammatory bowel disease when the clinical picture suggests it. A common pitfall is people removing gluten before testing, which produces false-negative results on celiac serology. Keep gluten in your diet until testing is done if your clinician recommends it.

If serious conditions are excluded and symptoms persist, consider whether the problem is a functional gut disorder—now often described as a disorder of gut-brain interaction—which includes IBS, functional bloating, and functional constipation. From there, you decide on a targeted plan: basic diet and lifestyle first, then structured diets or medical options when needed.

How do IBS and SIBO differ—and are the treatments the same?

They overlap, but they are distinct.

IBS (Irritable Bowel Syndrome) is diagnosed by symptom criteria: abdominal pain at least one day per week for the last three months, with onset at least six months earlier, and pain linked with a change in stool form or frequency. IBS comes in types—diarrhea-predominant, constipation-predominant, mixed, or unspecified.

Treatment is staged. First-line therapy addresses fiber distribution, fatty foods, caffeine, alcohol, hydration, and stress. These changes help roughly half of the people with IBS. If symptoms persist, second-line approaches like the low FODMAP diet can give the gut a break. When dietary strategies fail, medical options such as low-dose neuromodulators (a kind of neuromodulating antidepressant) are considered.

SIBO (Small Intestinal Bacterial Overgrowth) occurs when microbes that belong in the large intestine migrate and grow in the small intestine. The small intestine is far more sensitive to gas and acids, so SIBO can cause severe bloating and stool changes.

Diagnosis can be tricky. Breath tests measure hydrogen and methane after a sugar load, but interpretation is complex—gut motility and other factors influence the result. Rifaximin (an antibiotic that stays in the gut) is often used, but relapse is common unless underlying drivers are fixed—motility problems, frequent snacking (which disrupts the migrating motor complex), and chronic proton pump inhibitor use can all contribute.

Treatment for SIBO is usually more medical plus dietary: rifaximin where appropriate, diet modification, and addressing gut motility (longer fasting periods and minimizing constant snacking). For both IBS and SIBO, dietitians play a crucial role in crafting individualized plans.

Why is fiber so central to gut health—and how do you add it safely if you have a sensitive gut?

Fiber is the primary fuel for our gut microbes. Human cells lack the enzymes to digest many plant fibers, but microbes in the large intestine do break them down into short-chain fatty acids like butyrate. These metabolites are powerful messengers that support gut lining health, modulate immunity, and influence appetite and possibly mood.

That said, microbial fermentation produces gas. In people with a sensitive gut or IBS, a sudden influx of fiber can trigger uncomfortable gas, bloating, and pain. That’s why we recommend an even distribution of fiber across the day instead of loading it into one meal. Think of microbes like workers who prefer steady meals rather than being starved, then overfed.

General targets: about 30 grams of fiber per day is a useful guideline for most adults. If you have gut sensitivity, start lower (around 20 grams) and gradually “train” the gut by increasing fiber slowly over weeks and months. Practical steps: include a source of plant fiber at every meal—whole grains, vegetables, legumes, fruit, nuts, or seeds. Track tolerance and progress slowly.

What about fruit and fructose—should people with gut symptoms avoid fruit?

Fruit is nutritious, but some people with sensitive guts can only absorb a limited amount of fructose at one time. Eating a large bowl of fruit can overwhelm small intestinal absorption, leaving sugars to reach the colon, where microbes ferment them and produce gas.

Practical guidance: enjoy fruit, but spread servings across the day—typical guidance is around 80 grams per serving, three times a day rather than a single large portion. Pair fruit with protein or fat (Greek yogurt, nut butter) to improve tolerance and blunt blood sugar spikes.

What is the low FODMAP diet really for—and how do you reintroduce foods safely?

Low FODMAP is a therapeutic, short-term strategy designed to reduce fermentable carbohydrate intake so the gut can calm down. It is not intended as a long-term diet because it excludes many prebiotic-rich foods that are beneficial for the microbiome: garlic, onion, legumes, and certain fruits and vegetables.

The recommended approach is three stages: elimination (typically four to six weeks), careful reintroduction to test individual tolerances, and personalization—building back a diet that is as diverse as tolerated. Reintroduction is systematic: start with small amounts (for example, one tablespoon of chickpeas daily in week one, two tablespoons in week two) and increase gradually. That gradual “gut training” helps the microbiome adapt and prevents symptom flares.

What are the two main dietary pillars you recommend for general gut health?

There are two priority pillars backed by current research:

1. Plant diversity: Aim to eat across six plant groups regularly—whole grains, fruit, vegetables, legumes, herbs and spices, and nuts and seeds. Each group provides different plant chemicals that feed distinct microbes. Greater dietary diversity is associated with higher microbial diversity and lower risk for many chronic conditions.
2. Fermented foods: Including live fermented foods (yogurt, kefir, kimchi, sauerkraut, natto, miso, kombucha, aged cheeses) appear to increase microbial diversity and reduce markers of systemic inflammation in trials.

How many servings of fermented foods should I aim for?

Intervention trials that increased fermented food intake used multiple small servings per day—sometimes up to six small portions. These were not huge bowls, but little additions throughout the day: a spoon of kimchi, a small glass of kombucha, a few tablespoons of live yogurt. Start small and build habitually. If fermented dairy is not tolerated or avoided, consider other fermented options or a qualified probiotic when indicated.

Probiotics versus fermented foods: what’s the difference, and when should people take probiotic supplements?

Fermented foods and probiotics are not the same. Fermented foods are whole foods that contain live microbes and other compounds, while probiotics are specific strains of bacteria taken at a known dose for a specific health outcome. Scientific evidence for probiotics is strain-specific and dose-specific; you cannot assume a random multi-strain supplement will help a particular condition.

When supplements make sense:

• During and after antibiotics: certain strains (for example, LGG) have evidence to reduce antibiotic-associated diarrhea and support microbiome recovery. Take during the antibiotic course and for a week after.
• Infant colic: BB-12 has randomized controlled trial evidence reducing crying in some colicky infants.
• Upper respiratory infections: pooled analyses show some strains (BB-12 + LG) can reduce the duration of colds.
• Vaginal health: specific formulations combining certain lactobacilli and lactoferrin reduced relapse of thrush in trials.

Most other uses (weight loss, generalized “gut health” for everyone) lack robust evidence. If you do choose a probiotic, pick a product with strain names and clinical trial evidence for your specific concern. Avoid one-size-fits-all assumptions and avoid mixing many strains without data; they can antagonize each other.

How do you choose a probiotic product? Refrigerated or shelf-stable?

It depends on the strain and manufacturer validation. Some evidence-backed strains like LGG and BB-12 are shelf-stable at temperatures below about 25 degrees Celsius. Others require refrigeration. Look for reputable companies with transparent strain identification, dosage per serving, and published trials supporting the indication you care about. For antibiotics, consult the World Gastroenterology guidelines that list recommended strains and doses.

Are there supplements you commonly recommend?

We recommend targeted supplementation only when evidence supports it or when diet or testing shows a clear need:

• Vitamin D: If you are deficient, supplementing supports gut lining integrity and immune health.
• Omega-3: If you don’t eat oily fish twice a week, consider an omega-3 supplement for inflammation modulation and gut benefits.
• Psyllium husk: For constipation, there is strong clinical evidence that psyllium improves stool consistency and frequency.
• Peppermint oil capsules: There is evidence that these can be effective antispasmodics for IBS symptoms in some people.

What about microbiome stool tests sold direct-to-consumer? Do they help pick foods or probiotics?

Stool sequencing can describe bacterial composition, and it’s useful in research and for tracking changes pre- and post-intervention. However, current commercial tests are limited in actionable clinical accuracy for individual dietary prescriptions. Reasons:

• The microbiome includes bacteria, viruses, fungi, and other organisms; most tests focus only on bacteria.
• Presence of a microbe does not predict its function; the metabolites bacteria produce matter more than the mere name on a list.
• Many microbes remain poorly characterized at species and strain levels, and strain differences can radically change function.

Use these tests as motivational tools—to show measurable change after you improve diet diversity—but avoid using them as definitive guides to buy a specific supplement unless a clinician interprets the results within a broader clinical picture.

Does alcohol damage the gut—or can a glass of wine be helpful?

Alcohol has a dose-dependent effect. Small amounts of red wine contain polyphenols—plant chemicals that feed microbes and may be anti-inflammatory in small doses. However, more than a modest amount of alcohol increases gut permeability (leaky gut) and inflammation. If you don’t drink, you don’t need to start for polyphenols—eat dark chocolate or grapes instead. If you do drink, one small glass of red wine occasionally may offer more polyphenols than harm, but higher intake is harmful.

How does the gut influence mood—and what actually works for depression and anxiety?

There is an active gut-brain dialogue. The SMILES trial is a landmark randomized study that showed a Mediterranean-style, “gut-boosting” dietary intervention significantly improved depressive symptoms compared to social support alone. The intervention emphasized whole grains, legumes, vegetables, fruit, extra virgin olive oil, fermented dairy, and oily fish. Over 12 weeks, a substantial portion of participants moved out of the range of clinical depression.

That does not mean diet replaces medication. Participants usually stayed on their medicines during trials. Diet is an evidence-based adjunct and can be a first-line approach for people with mild to moderate symptoms or as part of a combined plan for those on medication.

Are there non-diet tools that help the gut-brain axis?

Yes. Two evidence-backed tools are gut-directed hypnotherapy and gut-directed yoga flow (a short, specific sequence of movements and breathing). Trials comparing the low FODMAP diet to gut-directed yoga found similar improvements for some patients. Megan partnered with a yoga specialist to convert clinical trial protocols into a practical 10-minute daily sequence that focuses on diaphragmatic breathing, cat-cow movements, gentle twists, and poses that relax the enteric nervous system.

How should gut care change across female life stages—pregnancy, perimenopause, and menopause?

The base strategies—plant diversity and fermented foods—apply at every stage, but priorities shift:

• Pregnancy: Focus on safe, nutrient-dense foods, adequate protein, and treating any deficiencies (vitamin D, iron) under clinician guidance.
• Perimenopause and menopause: Pay attention to the estrobolome—a group of gut microbes that reactivate inactive estrogen in the gut. When ovarian estrogen falls during menopause, retaining healthy estrobolome activity becomes important. Dietary tools that have shown benefit include phytoestrogen-rich foods such as soy, plus omega-3s and antioxidants. Observational data suggest that daily oily fish and legumes may delay menopause timing by several years. Emphasize protein to prevent muscle loss—spread protein evenly across meals and aim for a slightly higher daily protein intake than younger adults.

What do you recommend for women with PCOS or endometriosis?

Both conditions show links with the microbiome. Endometriosis patients have higher rates of IBS symptoms, and some studies show that low FODMAP can help with pelvic pain in the short term. PCOS research is evolving; animal studies that transplanted microbiota from PCOS individuals into rodents produced PCOS-like metabolic and hormonal changes. That suggests the microbiome plays a contributory role. We focus on improving blood sugar regulation (pair carbs with protein/fat), increasing fiber and plant diversity, ensuring vitamin D sufficiency, and considering specific probiotic trials as the evidence develops.

What does a gut-supportive day of eating look like in real life?

Megan’s practical day often looks like this:

• Breakfast: Overnight fermented oats made with kefir, oats, chia, grated carrot or fruit, dates, and walnuts. The fermentation increases flavor and adds live microbes.
• Snack: Handful of mixed nuts or a piece of fruit with Greek yogurt.
• Lunch: Leftover stir fry or salad with a can of mixed legumes, a whole grain, lots of roasted vegetables, herbs, and seeds—ticking off the “super six” plant groups.
• Dinner: Quick homemade pizza or wrap with vegetables, legumes or beans on the side, frozen peas, tomato paste, and a portion of oily fish a few times per week.
• Dessert: Frozen berries with kefir and a small piece of dark chocolate.

The theme is variety, simplicity, and keeping home-cooked items handy, so convenience does not mean ultra-processed.

What three simple, high-impact habits should women start with today?

Start small and build consistency. Megan recommends three easy, accessible changes:

1. Mixed frozen berries—cheap, shelf-stable, nutrient-dense, and full of polyphenols and antioxidants that help brain perfusion and feed microbes.
2. A can of mixed legumes—versatile, fiber-rich, prebiotic, and a fast way to get a dose of plant protein and fermentable fiber into meals.
3. Frozen cauliflower—adds bulk and phytonutrients to smoothies, soups, and sauces with minimal prep.

On a behavioral level, ask yourself at each meal: “What on this plate is feeding my microbes?” That mindset shift turns feeding your gut into a routine rather than a chore

Should we worry about food additives like emulsifiers?

We don’t want alarmism, but emerging research suggests some emulsifiers (carrageenan, polysorbate 80) may negatively affect the microbiome and contribute to disease in vulnerable groups. Trials in people with Crohn’s disease showed benefits when patients reduced emulsifier intake. Practical advice: minimize highly processed convenience products—especially plant-based convenience options that may contain multiple additives—and make batches of whole-food alternatives at home where possible.

FAQs

How much fiber should I aim for, and how fast can I increase it?

Aim for around 25 to 30 grams per day as a general target. If you have gut sensitivity, begin around 15–20 grams and increase by a few grams every one to two weeks. Distribute fiber evenly across meals to avoid overwhelming your gut microbes and triggering gas.

How long should I stay on the low FODMAP diet?

Treat it as a short-term therapeutic tool: typically 4–6 weeks for elimination, followed by a structured reintroduction and personalization. The goal is to return to the most diverse diet tolerated.

Can I take a probiotic as a daily insurance policy?

Not usually. Probiotics are most useful for specific indications where strain-level evidence exists—during and after antibiotics, infant colic (BB-12), some cold and flu prevention (BB-12 + LG), and certain vaginal health uses. For general gut health, prioritize food-based strategies first.

Which probiotic should I take after antibiotics?

Look for strains with clinical trials supporting antibiotic-associated diarrhea prevention—LGG and BB-12 are commonly studied. Take the probiotic during the antibiotic course and for about a week after, unless your clinician advises differently.

Are stool microbiome tests worth it?

They can be motivating and useful to track change after interventions, but they are not yet reliable tools to prescribe specific diets or supplements on their own. Use them judiciously and ideally with a clinician who can interpret results in context.

What is a realistic alcohol approach if I care about gut health?

If you drink, keep intake modest. One small glass of red wine occasionally may deliver polyphenols without causing harm. Higher amounts increase gut permeability and inflammation. If you don’t drink, you can get polyphenols from grapes, dark chocolate, and other plant foods.

Final practical checklist to start today

• Eat from the “super six” plant groups most days: whole grains, fruit, vegetables, legumes, herbs/spices, and nuts/seeds.
• Include a fermented food regularly—start with a small spoonful or a small cup of yogurt, kefir, kimchi, or kombucha.
• Distribute fiber across all meals; aim for a gradual approach to increase toward 30 grams/day.
• If you have IBS, try first-line basic changes (fiber distribution, hydration, reduce caffeine/alcohol, avoid excess fat/spicy foods). If needed, use low FODMAP with a trained dietitian and complete reintroduction.
• Use probiotics only for indications with strain-level evidence and take them at the recommended dose and duration.
• Address sleep, stress, and movement—10 minutes of gut-directed yoga flow or diaphragmatic breathing daily can be powerful.
• Check vitamin D and consider omega-3s if you don’t eat oily fish regularly.

We want to help you feel empowered to care for your gut with realistic, evidence-based steps. Food is the foundation—diversity, fermented foods, and steady fiber intake go a long way. Use probiotics and supplements strategically, not as a shortcut. And remember: small, consistent changes that fit your life will win over perfect but unsustainable plans.

If you want to explore more resources from Dr. Megan Rossi, she maintains clinical and consumer material, including behavior-friendly protocols and research summaries that translate science into practice.

This article was created from the video The Hidden Connection Between Your Gut & Your Hormones ft. Dr. Megan Rossi | SHE MD for Dr. Thais Aliabadi’s website.