Is this approach for IBS or chronic gut symptoms?

This optimization approach is for people without active gut symptoms who want to use their microbiome to support performance. If you have active pain, bloating, or diarrhea, see our SIBO and IBS guide first. We treat structural and symptomatic problems before optimization work.

Do I need to stop eating gluten?

Whether you need to stop gluten depends on you. For most patients optimizing performance, reducing gluten is helpful but not strictly required. Patients with diagnosed celiac disease or non-celiac gluten sensitivity should avoid it strictly. Many driven patients feel sharper on a lower-gluten diet, even without a formal sensitivity diagnosis.

Are probiotic sodas useful?

Most probiotic sodas have very low doses of strains that often die before reaching the colon. They are usually marketing hype. We use spore-based probiotics or targeted clinical-grade strains that survive stomach acid and actually colonize the gut, when appropriate.

What is GI-MAP testing?

GI-MAP is a PCR-based stool test that measures DNA from gut bacteria, parasites, viruses, and yeasts. It also measures markers of inflammation (calprotectin), gluten sensitivity (anti-gliadin antibodies), and digestive function (pancreatic elastase). It gives a much more detailed picture than older stool culture methods.

How long does it take to change the microbiome?

Meaningful microbiome changes typically take 4 to 12 weeks of consistent dietary and supplement work. Some changes happen within days, but stable changes that support long-term health take months. Diet has the biggest single influence, more than any single probiotic.

What foods support a healthy microbiome?

Foods that support a healthy microbiome include diverse fiber sources (vegetables, fruits, legumes, whole grains), fermented foods (yogurt, kefir, sauerkraut, kimchi), polyphenol-rich foods (berries, dark chocolate, olive oil, green tea), and adequate protein. Variety matters more than any single "superfood."

Can stress damage the gut?

Yes, chronic stress damages the gut. Cortisol thins the protective mucus layer, weakens tight junctions between gut cells, and disrupts the microbiome. The vagus nerve, which usually maintains gut tone, gets blunted. Stress-reduction practices are a real part of gut care.

Does alcohol affect the microbiome?

Alcohol affects the microbiome by increasing gut permeability, killing beneficial bacteria, and feeding inflammatory species. Even moderate drinking shows up in microbiome data. Patients optimizing gut health usually benefit from cutting back, particularly during the first 6 months.

Are food sensitivity tests accurate?

Food sensitivity panels (IgG, IgA tests) show patterns of immune exposure to foods, not true sensitivities. They can guide an elimination protocol but should not be treated as definitive diagnoses. The gold standard is still an elimination diet followed by careful reintroduction.

What is the "gut-skin axis"?

The gut-skin axis describes the connection between gut health and skin conditions. Gut inflammation drives skin inflammation in conditions like rosacea, eczema, psoriasis, and acne. Bacterial fragments from a leaky gut reach the skins immune system. Treating gut health often improves skin within months.

What is short-chain fatty acid (SCFA) production?

Short-chain fatty acids (SCFAs) like butyrate, propionate, and acetate are produced when gut bacteria ferment fiber. Butyrate is the primary fuel for cells lining the large intestine. SCFAs lower inflammation, support insulin sensitivity, and even reach the brain. Higher SCFA production correlates with better metabolic and cognitive health.

How does the vagus nerve affect gut function?

The vagus nerve is the main highway between your gut and your brain. It controls gut motility (the muscle contractions that move food along), digestive enzyme release, and inflammation. Higher vagal tone (a stronger "rest and digest" signal) correlates with better gut function. Resonance breathing, cold exposure, and gargling all stimulate vagal tone.

What is Akkermansia muciniphila and why does it matter?

Akkermansia muciniphila is a keystone gut bacterium that lives in the mucus layer of the intestine. It supports a tight gut barrier, modulates immune function, and is associated with leaner body composition and better metabolic markers. Polyphenols from cranberries, pomegranate, and grapes appear to support Akkermansia growth.

How does the microbiome influence mood?

The microbiome influences mood through several pathways: producing neurotransmitters, regulating inflammation, signaling through the vagus nerve, and producing short-chain fatty acids that reach the brain. Patients with depression and anxiety often have measurably different gut microbiomes than healthy controls. Some probiotic strains have shown antidepressant effects in trials.

What are "psychobiotics"?

Psychobiotics are probiotic strains that produce mental health benefits. Examples include *Lactobacillus rhamnosus* JB-1 and *Bifidobacterium longum* 1714. Studies show effects on stress, anxiety, and cognitive performance. The field is young, and individual responses vary, but the science is real.

How does the microbiome change with aging?

The microbiome changes with aging by losing diversity. Older adults tend to have fewer keystone species, less SCFA production, and more inflammatory bacteria. This change contributes to "inflammaging" (chronic low-grade inflammation with age). Regular fiber intake, fermented foods, and physical activity help slow these changes.

What is the connection between exercise and the microbiome?

Exercise reshapes the microbiome favorably. Regular aerobic and resistance training increases microbial diversity, raises butyrate-producing species, and supports a tighter gut barrier. Endurance athletes have unique microbiome patterns linked to better lactate processing.

Can the microbiome affect athletic performance?

Yes, the microbiome affects athletic performance. Some bacteria break down lactate (a workout byproduct) and produce energy substrates. Others affect inflammation and recovery. Studies in elite athletes have shown unique microbial signatures linked to better performance. Over-training and high-stress training can disrupt the microbiome.

What is the role of polyphenols in gut health?

Polyphenols are plant compounds in foods like berries, dark chocolate, olive oil, green tea, and red wine. They support beneficial bacteria like Akkermansia, lower inflammation, and act as antioxidants. Many polyphenols are not fully absorbed; instead, they reach the gut where bacteria ferment them into bioactive metabolites.

How does the microbiome influence weight?

The microbiome influences weight by shaping calorie extraction from food, hunger and fullness signals, and inflammation. Patients with low microbial diversity often have more weight gain and more insulin resistance. The microbiome is one factor among many, not the whole story.

What is leaky gut and how does it relate to performance?

Leaky gut, properly called intestinal permeability, is when the gut lining lets large molecules slip into the bloodstream. The immune system reacts, driving chronic low-grade inflammation. This inflammation can blunt training adaptations, worsen sleep, and affect cognition. See our Leaky Gut guide for more.

Can probiotics cause harm?

Probiotics can cause harm in specific situations: in patients with immune compromise, after surgery, with central lines, or in cases of SIBO where adding more bacteria worsens overgrowth. They can also cause temporary bloating or gas in the first weeks. We choose strains carefully based on the situation.

What is the role of fiber diversity?

Fiber diversity matters more than fiber quantity for microbiome health. Different bacteria prefer different fibers. A diet with 30 to 40 plant species per week supports a more diverse microbiome than a diet with 5 species, even at the same total fiber gram count. The American Gut Project showed this clearly.

How does the microbiome interact with the immune system?

About 70% of the immune system lives in or near the gut. The microbiome trains the immune system to distinguish friend from foe. Disruptions in the microbiome are linked to autoimmune disease, allergies, and infections. A diverse, balanced microbiome supports a calibrated immune response.

What about fecal microbiota transplant (FMT)?

Fecal microbiota transplant (FMT) is the transfer of gut bacteria from a healthy donor to a patient. It is FDA-approved for *Clostridioides difficile* infection and is being studied for other conditions like ulcerative colitis, autism, and metabolic syndrome. It is not yet a routine performance tool but represents an exciting frontier.

How do antibiotics affect the microbiome long-term?

Antibiotics can affect the microbiome for months to years after a single course. They reduce diversity, kill beneficial species along with harmful ones, and can favor opportunistic microbes. We use antibiotics carefully and pair them with rebuilding strategies (probiotics, prebiotics, fermented foods) when used.

What is the connection between sleep and the microbiome?

Sleep and the microbiome influence each other. The microbiome follows a daily rhythm, and disrupted sleep patterns disrupt the microbiome. Conversely, certain gut bacteria produce GABA and serotonin, which affect sleep quality. Patients who fix sleep often see microbiome improvements without specific gut treatments.

How does seed oil intake affect gut health?

Industrial seed oils (soybean, corn, canola) are high in omega-6 fatty acids. Heavy intake, particularly of fried and ultra-processed foods, may raise gut inflammation in some patients. The science is debated. Cutting back on fried fast food and ultra-processed snacks helps gut health regardless of the seed oil debate.

What is the connection between the microbiome and Alzheimer's risk?

Some early research links microbiome differences to Alzheimer's risk and cognitive decline. The mechanism may involve inflammation, immune signaling, and possibly bacterial fragments reaching the brain. Patients with metabolic syndrome and gut dysbiosis tend to have higher dementia risk. This is an active area of research.

Is this approach for IBS or chronic gut symptoms?

This optimization approach is for people without active gut symptoms who want to use their microbiome to support performance. If you have active pain, bloating, or diarrhea, see our SIBO and IBS guide first. We treat structural and symptomatic problems before optimization work.

Do I need to stop eating gluten?

Whether you need to stop gluten depends on you. For most patients optimizing performance, reducing gluten is helpful but not strictly required. Patients with diagnosed celiac disease or non-celiac gluten sensitivity should avoid it strictly. Many driven patients feel sharper on a lower-gluten diet, even without a formal sensitivity diagnosis.

Are probiotic sodas useful?

Most probiotic sodas have very low doses of strains that often die before reaching the colon. They are usually marketing hype. We use spore-based probiotics or targeted clinical-grade strains that survive stomach acid and actually colonize the gut, when appropriate.

What is GI-MAP testing?

GI-MAP is a PCR-based stool test that measures DNA from gut bacteria, parasites, viruses, and yeasts. It also measures markers of inflammation (calprotectin), gluten sensitivity (anti-gliadin antibodies), and digestive function (pancreatic elastase). It gives a much more detailed picture than older stool culture methods.

How long does it take to change the microbiome?

Meaningful microbiome changes typically take 4 to 12 weeks of consistent dietary and supplement work. Some changes happen within days, but stable changes that support long-term health take months. Diet has the biggest single influence, more than any single probiotic.

What foods support a healthy microbiome?

Foods that support a healthy microbiome include diverse fiber sources (vegetables, fruits, legumes, whole grains), fermented foods (yogurt, kefir, sauerkraut, kimchi), polyphenol-rich foods (berries, dark chocolate, olive oil, green tea), and adequate protein. Variety matters more than any single "superfood."

Can stress damage the gut?

Yes, chronic stress damages the gut. Cortisol thins the protective mucus layer, weakens tight junctions between gut cells, and disrupts the microbiome. The vagus nerve, which usually maintains gut tone, gets blunted. Stress-reduction practices are a real part of gut care.

Does alcohol affect the microbiome?

Alcohol affects the microbiome by increasing gut permeability, killing beneficial bacteria, and feeding inflammatory species. Even moderate drinking shows up in microbiome data. Patients optimizing gut health usually benefit from cutting back, particularly during the first 6 months.

Are food sensitivity tests accurate?

Food sensitivity panels (IgG, IgA tests) show patterns of immune exposure to foods, not true sensitivities. They can guide an elimination protocol but should not be treated as definitive diagnoses. The gold standard is still an elimination diet followed by careful reintroduction.

What is the "gut-skin axis"?

The gut-skin axis describes the connection between gut health and skin conditions. Gut inflammation drives skin inflammation in conditions like rosacea, eczema, psoriasis, and acne. Bacterial fragments from a leaky gut reach the skins immune system. Treating gut health often improves skin within months.

What is short-chain fatty acid (SCFA) production?

Short-chain fatty acids (SCFAs) like butyrate, propionate, and acetate are produced when gut bacteria ferment fiber. Butyrate is the primary fuel for cells lining the large intestine. SCFAs lower inflammation, support insulin sensitivity, and even reach the brain. Higher SCFA production correlates with better metabolic and cognitive health.

How does the vagus nerve affect gut function?

The vagus nerve is the main highway between your gut and your brain. It controls gut motility (the muscle contractions that move food along), digestive enzyme release, and inflammation. Higher vagal tone (a stronger "rest and digest" signal) correlates with better gut function. Resonance breathing, cold exposure, and gargling all stimulate vagal tone.

What is Akkermansia muciniphila and why does it matter?

Akkermansia muciniphila is a keystone gut bacterium that lives in the mucus layer of the intestine. It supports a tight gut barrier, modulates immune function, and is associated with leaner body composition and better metabolic markers. Polyphenols from cranberries, pomegranate, and grapes appear to support Akkermansia growth.

How does the microbiome influence mood?

The microbiome influences mood through several pathways: producing neurotransmitters, regulating inflammation, signaling through the vagus nerve, and producing short-chain fatty acids that reach the brain. Patients with depression and anxiety often have measurably different gut microbiomes than healthy controls. Some probiotic strains have shown antidepressant effects in trials.

What are "psychobiotics"?

Psychobiotics are probiotic strains that produce mental health benefits. Examples include *Lactobacillus rhamnosus* JB-1 and *Bifidobacterium longum* 1714. Studies show effects on stress, anxiety, and cognitive performance. The field is young, and individual responses vary, but the science is real.

How does the microbiome change with aging?

The microbiome changes with aging by losing diversity. Older adults tend to have fewer keystone species, less SCFA production, and more inflammatory bacteria. This change contributes to "inflammaging" (chronic low-grade inflammation with age). Regular fiber intake, fermented foods, and physical activity help slow these changes.

What is the connection between exercise and the microbiome?

Exercise reshapes the microbiome favorably. Regular aerobic and resistance training increases microbial diversity, raises butyrate-producing species, and supports a tighter gut barrier. Endurance athletes have unique microbiome patterns linked to better lactate processing.

Can the microbiome affect athletic performance?

Yes, the microbiome affects athletic performance. Some bacteria break down lactate (a workout byproduct) and produce energy substrates. Others affect inflammation and recovery. Studies in elite athletes have shown unique microbial signatures linked to better performance. Over-training and high-stress training can disrupt the microbiome.

What is the role of polyphenols in gut health?

Polyphenols are plant compounds in foods like berries, dark chocolate, olive oil, green tea, and red wine. They support beneficial bacteria like Akkermansia, lower inflammation, and act as antioxidants. Many polyphenols are not fully absorbed; instead, they reach the gut where bacteria ferment them into bioactive metabolites.

How does the microbiome influence weight?

The microbiome influences weight by shaping calorie extraction from food, hunger and fullness signals, and inflammation. Patients with low microbial diversity often have more weight gain and more insulin resistance. The microbiome is one factor among many, not the whole story.

What is leaky gut and how does it relate to performance?

Leaky gut, properly called intestinal permeability, is when the gut lining lets large molecules slip into the bloodstream. The immune system reacts, driving chronic low-grade inflammation. This inflammation can blunt training adaptations, worsen sleep, and affect cognition. See our Leaky Gut guide for more.

Can probiotics cause harm?

Probiotics can cause harm in specific situations: in patients with immune compromise, after surgery, with central lines, or in cases of SIBO where adding more bacteria worsens overgrowth. They can also cause temporary bloating or gas in the first weeks. We choose strains carefully based on the situation.

Microbiome & Gut-Brain Performance | Philadelphia

TL;DR30-second take

Gut health affects far more than digestion. Your microbiome influences mood, focus, immunity, and metabolism. We use stool DNA testing, targeted dietary changes, and selective probiotics to engineer a microbiome that supports cognitive performance, lower inflammation, and better metabolic health.

Why Does Gut Health Matter for Performance?

You might not have IBS or stomach pain. You might feel generally fine. But you notice that your energy dips at 2 PM, your focus feels staticky, you catch every cold, and your skin is "off." Often this is a microbiome efficiency problem.

Your gut bacteria actively control your biology. They produce neurotransmitters, train your immune system, regulate inflammation, and shape how much energy you extract from food.¹

"We used to think the gut just digested food. We now know it produces 90% of your serotonin (a mood and sleep neurotransmitter) and about 50% of your dopamine (a motivation and focus neurotransmitter). If your microbiome is off, your mood and focus will be too."

What Is the Gut-Brain Axis?

The gut-brain axis is the two-way communication network between the gut and the brain. The vagus nerve (the main nerve of the parasympathetic system) runs between them, carrying signals in both directions. The gut also produces hormones and metabolites that influence the brain.

This is why anxiety can give you stomach symptoms, and why gut inflammation can fuel brain fog and low mood.

How Is This Different from Standard GI Care?

Gastroenterologists are experts in structural disease like Crohn's disease, ulcerative colitis, and cancer. Their job is to make sure you are not dying. That work is essential.

Our job is to help you function and feel your best. Once structural disease is ruled out (or being managed by GI), we focus on functional optimization.

Feature	Standard GI	"Gut Health" Influencer	Fishtown Medicine
Goal	Rule out disease (cancer, IBD)	Sell supplements	Optimize cognition, immunity, metabolism
Testing	Endoscopy, colonoscopy	Unvalidated sensitivity tests	PCR DNA stool analysis, breath tests, lab markers
Focus	Anatomy and structure	"Bloating" only	Gut-brain axis, immunity, metabolic markers

What Is the Strategic Roadmap?

We do not throw random probiotics at you. We map the ecosystem and intervene with precision. The framework is "weed, seed, feed."

1. Audit (DNA Sequencing)

We use the GI-MAP test (a stool DNA panel) to sequence your microbiome.

Keystone species: Do you have Akkermansia muciniphila (a bacterium linked to better metabolic health and a tighter gut barrier)?⁴
Inflammation markers: Is calprotectin elevated, suggesting silent gut inflammation?
Dysbiosis: Are opportunistic bacteria stealing nutrients or producing inflammatory toxins?

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2. Weed (Targeted Removal)

If we find "energy vampires" (bacteria that produce inflammatory byproducts like LPS, a fragment of bacterial cell walls that drives inflammation), we remove them.

The strategy: Targeted herbal antimicrobials (oregano oil, berberine), prescription antibiotics like rifaximin when needed, and dietary changes that starve harmful species without harming the good guys.

3. Seed and Feed (Restoration)

This is where performance gains happen. We introduce specific strains for specific goals.

For anxiety and focus: Psychobiotics like Lactobacillus rhamnosus that communicate directly with the vagus nerve.
For metabolic health: Prebiotic fibers (like partially hydrolyzed guar gum and resistant starch) that feed butyrate-producing bacteria. Butyrate is a short-chain fatty acid that fuels gut cells and supports insulin sensitivity.⁵
For immunity: Spore-based probiotics like Bacillus coagulans that survive stomach acid and modulate immune function.

Guidance from the Clinic

"70% of your immune system lives in the gut. If your microbiome is inflamed, you cannot focus, you catch every cold, and your sleep gets worse. Fixing this is not glamorous, but the payoff is real."

A common question I hear: "Should I just take a probiotic?"

My honest answer: maybe, but not blindly. Random probiotics can help, but they often miss the target. If your problem is methane-producing archaea (a class of microbes that look like bacteria), most probiotics will not touch it. If your problem is low diversity, a single strain probiotic does not fix it. We test first, then choose.

Scientific References

Cryan JF, et al. The Microbiota-Gut-Brain Axis. Physiol Rev. 2019;99(4):1877-2013.
Mailing LJ, et al. Exercise and the Gut Microbiome. Exerc Sport Sci Rev. 2019;47(2):75-85.
McDonald D, et al. American Gut: an Open Platform for Citizen Science Microbiome Research. mSystems. 2018;3(3):e00031-18.
Sonnenburg JL, Sonnenburg ED. The Ancestral and Industrialized Gut Microbiota and Implications for Human Health. Nat Rev Microbiol. 2019;17(6):383-390.
Tilg H, et al. The Intestinal Microbiota in Metabolic Disease. Nat Rev Gastroenterol Hepatol. 2014;11(11):649-658.

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Fishtown Medicine | Performance

2418 E York St, Philadelphia, PA 19125(267) 360-7927 hello@fishtownmedicine.comHSA/FSA Eligible

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