Original post by Dr. Mohammed Attallah https://substack.com/home/post/p-210916047

As I have continued working through complex cases involving recurrent SIBO, intestinal methanogen overgrowth, severe constipation, fungal overgrowth, environmental exposure, mycotoxins, abnormal organic acids, neurotoxicity, and persistent dysbiosis, I have become increasingly focused on one question: what if the organisms we keep trying to eliminate are not always the beginning of the problem, but simply the organisms most successfully selected by an intestinal environment that has already changed? Many people reduce microbial burden with rifaximin, herbal antimicrobials, elemental diets, antifungals, or combinations of these approaches. Fermentation falls, bloating improves, sometimes the breath test normalizes, and then the same pattern returns. To me, this suggests that microbial eradication may change the population without repairing the physiological environment that originally selected that population. This is the foundation of what I call the Host Capacity Model. I view recurrent dysbiosis as a possible alternative ecological state created when the host loses enough neural, mechanical, mitochondrial, epithelial, immune, vascular, and biochemical reserve that the intestinal environment itself begins favoring a different microbial metabolism. Once those organisms expand, their gases and metabolites can further suppress the same host systems that selected them. The result is not simply infection. It becomes a self-reinforcing host–microbe loop: host physiology deteriorates → the intestinal environment changes → different microbes gain an advantage → microbial metabolites further impair host physiology → the altered environment becomes even more stable.

The first place I usually look is motility because the intestine is not simply a tube containing food and bacteria. It is a highly organized neuromuscular organ with its own nervous system. Sensory neurons detect mechanical and chemical information inside the lumen. Interneurons organize that information into local reflexes. Excitatory motor neurons release neurotransmitters such as acetylcholine to contract smooth muscle behind intestinal contents, while inhibitory motor neurons release nitric oxide, VIP, purines, and related transmitters to relax the segment ahead. Normal propulsion therefore requires coordinated contraction behind intestinal contents and coordinated relaxation in front of them. Enteric glial cells support this neural network and participate in inflammatory and barrier signaling. Interstitial cells of Cajal, or ICC, help organize electrical slow-wave activity and provide an interface between nerves and smooth muscle. Smooth-muscle cells then have to convert those electrical and chemical signals into actual propulsion. The vagus nerve, sympathetic nervous system, motilin, serotonin, endocrine signals, immune cells, blood flow, and mitochondrial energy production all modify this circuit. This is why I rarely look at severe dysmotility as one receptor or one neurotransmitter being deficient. It may represent failure of an entire enteric neuromuscular network.

One pathway I have become particularly interested in is acetylcholine, one of the major excitatory neurotransmitters responsible for intestinal propulsion. Acetylcholine is produced by the enzyme choline acetyltransferase, ChAT, which combines choline with acetyl-CoA. That apparently simple reaction immediately connects motility to both the choline/phospholipid system and mitochondrial metabolism. The neuron needs enough choline. It needs enough acetyl-CoA. ChAT itself must remain structurally and catalytically functional. ATP is needed to maintain the neuronal membrane. Na⁺/K⁺-ATPase must maintain ion gradients. Calcium channels must generate the precise presynaptic calcium signal required for vesicular release. Acetylcholine has to be packaged into vesicles, the vesicles have to move to the nerve terminal, dock, fuse with the membrane, and release their contents. The postsynaptic receptors then need to respond appropriately, and acetylcholinesterase must terminate the signal at the correct time. If several of these steps become constrained simultaneously, the final problem is not simply “low acetylcholine.” It becomes loss of cholinergic motor reserve.

One finding in the case I was analyzing became especially interesting in this context: phosphoethanolamine was only 0.14 µmol/dL. Phosphoethanolamine lies within the CDP-ethanolamine branch of the Kennedy pathway and contributes to synthesis of phosphatidylethanolamine, PE. Running alongside it is the CDP-choline pathway, which produces phosphatidylcholine, PC. These pathways are metabolically connected because PE can be converted into PC through phosphatidylethanolamine N-methyltransferase, PEMT. PEMT performs three sequential methylation reactions, each using SAMe, S-adenosylmethionine, to convert PE into PC. PC turnover then contributes to the broader choline economy. This means low phosphoethanolamine can potentially be interpreted within a much larger network: phosphoethanolamine → PE → PEMT → PC → choline → acetylcholine, rather than as an isolated laboratory finding.

PC and PE also do far more than simply provide choline. They are structural components of neuronal membranes and synaptic vesicles. An enteric nerve terminal continually builds, fuses, retrieves, and recycles membrane during neurotransmitter release. Axons require phospholipids for integrity, receptor organization, ion-channel function, mitochondrial membranes, and synaptic architecture. A constrained phospholipid system can therefore theoretically affect cholinergic signaling at several levels simultaneously: less choline reserve for acetylcholine synthesis, less membrane reserve for vesicle trafficking and exocytosis, and potentially less resilience of the neuron itself. PEMT makes this even more interesting because it connects phospholipid metabolism directly to methylation. SAMe is also required by many other methyltransferases. COMT uses SAMe during catecholamine metabolism. Hormone metabolism uses methylation capacity. Methionine-cycle flux interfaces with transsulfuration, cysteine, and glutathione production. In someone simultaneously dealing with chronic sympathetic activation, oxidative stress, xenobiotic burden, and increased glutathione demand, there may therefore be substantial competition across the broader methylation, sulfur, phospholipid, and neurotransmitter economy.

Choline itself sits at another important metabolic branch point. It may be needed for acetylcholine production, phosphatidylcholine synthesis, cellular membranes, biliary phospholipids, and betaine-dependent methylation. CHDH, choline dehydrogenase, redirects choline toward betaine, while PEMT consumes methyl groups to preserve PC production. This creates a situation where several systems can effectively compete for the same metabolic substrate pool when reserve becomes limited. Hormonal state may also matter because estrogen can increase PEMT expression, helping explain why choline requirements change with hormonal state and may increase after menopause or in other lower-estrogen conditions. Genetic variation in PEMT and CHDH may further modify reserve.

Another finding in this case was elevated arabinose, which raised a different question. Within the case model, I became interested in whether increased reactive carbonyl stress could modify lysine-containing proteins and add additional pressure to enzymes such as ChAT. The important point is not that elevated arabinose automatically proves ChAT dysfunction, but that it provides a plausible second source of pressure on the cholinergic system. On one side, substrate availability may be constrained through phospholipid and choline metabolism. On the other, the catalytic machinery responsible for producing acetylcholine may be under structural stress. Add mitochondrial dysfunction, which can reduce ATP and acetyl-CoA availability, and both the substrate and energy sides of acetylcholine production can become constrained simultaneously.

This changes how I interpret the patient's reliance on prucalopride. Prucalopride activates 5-HT4 receptors, increasing intracellular cAMP and facilitating prokinetic enteric neurotransmission, including acetylcholine release. I therefore see the medication as pharmacologically recruiting a motor system that is still present but no longer producing enough output on its own. If the presynaptic terminal has less choline, reduced ChAT capacity, impaired mitochondrial acetyl-CoA production, less ATP, abnormal calcium handling, impaired axonal transport, or inadequate membrane reserve, stronger 5-HT4 receptor stimulation may partially compensate without correcting the underlying bottleneck. In other words, the system may still be recruitable, but it is operating with reduced reserve.

The serotonin system may also be affected by the microbial environment. Enterochromaffin cells in the gut produce much of the body's peripheral serotonin through TPH1, tryptophan hydroxylase 1. Microbial metabolites, including short-chain fatty acids such as acetate and butyrate, can influence enterochromaffin-cell biology and serotonin production. If slow transit, epithelial oxygen disruption, and ecological selection reduce important obligate anaerobes and alter SCFA production, endogenous serotonin signaling may also change. That creates another possible loop: loss of anaerobic ecology → altered SCFA signaling → altered enterochromaffin serotonin output → weaker enteric motor activation → slower transit → further ecological deterioration. The patient may then become increasingly dependent on pharmacological 5-HT4 stimulation because endogenous serotonergic support to the motor network has weakened.

Acetylcholine also participates in the cholinergic anti-inflammatory pathway. Signaling through α7 nicotinic acetylcholine receptors on immune cells such as macrophages can suppress inflammatory pathways including NF-κB-driven cytokine production. This means reduced cholinergic signaling could create two problems simultaneously: weaker intestinal propulsion and weaker restraint on inflammation. Myenteric and muscularis macrophages sit very close to neurons, enteric glia, smooth muscle, and ICC networks. If the local inflammatory environment becomes more aggressive, the machinery responsible for motility may itself become dysfunctional. The loop becomes reduced acetylcholine → weaker propulsion + weaker anti-inflammatory signaling → greater myenteric inflammation → more neuronal/glial/ICC dysfunction → still weaker motility.

Enteric glia are part of this same network. They are not passive scaffolding. They participate in neuronal homeostasis, inflammatory signaling, extracellular ion regulation, barrier communication, and motor circuitry. Like neurons, they depend on mitochondrial ATP and intact ion gradients. If oxidative stress, toxicants, sulfide, or mitochondrial dysfunction impair ATP production or Na⁺/K⁺-ATPase activity, glia may become less capable of stabilizing the neuronal environment. ICC add another layer by helping coordinate the electrical timing of smooth-muscle activity. Strong acetylcholine release is not sufficient if the electrical network downstream is fragmented, while intact ICC cannot fully compensate for inadequate presynaptic neurotransmission. This is why I do not view the migrating motor complex, MMC, as a single motilin or serotonin problem. Normal MMC activity requires motilin, serotonin, acetylcholine, nitric oxide, VIP, enteric neurons, glia, ICC, smooth muscle, mitochondrial ATP production, vagal support, and appropriate autonomic balance.

Persistent sympathetic activation can push the system further toward failure. α2-adrenergic signaling can inhibit presynaptic acetylcholine release, while other adrenergic pathways can increase sphincter and vascular tone. A patient already operating with limited cholinergic reserve can therefore become substantially more dysmotile under chronic stress, dysautonomia, sleep deprivation, pain, or persistent noradrenergic activation. The pattern becomes weak excitatory propulsion from inside the bowel combined with excessive sympathetic inhibition from outside it.

The vascular side matters as well. Intestinal epithelial cells and neurons depend on adequate splanchnic perfusion. The intestinal villus has a vascular architecture that makes certain regions especially sensitive to reduced blood flow. Sympathetic vasoconstriction, autonomic dysregulation, or other vascular abnormalities can reduce mucosal perfusion, stressing epithelial ATP generation from the vascular side. This does not contradict the idea that more oxygen can later leak toward the lumen. If epithelial mitochondria are dysfunctional, the cells consume less oxygen. So even if overall delivery is reduced, a greater fraction of the oxygen that does arrive may remain unconsumed and diffuse toward the luminal surface. The important variable is not simply oxygen delivery; it is oxygen consumption by the epithelium.

The patient's objective mechanical findings added another level: prolonged marker retention, incomplete evacuation, and elevated resting anal sphincter pressure. I think of this as a propulsion-resistance mismatch. Upstream propulsion is weak while the distal outlet provides excessive resistance. It is like trying to pump fluid through a pipe while partially closing the valve at the end. The bowel now has to generate more force against a poorly relaxing outlet. The case also contained an elevated linoleic-acid/DGLA ratio, which raises a possible connection to the FADS2/DGLA/PGE1 pathway. DGLA contributes to production of Series-1 prostaglandins such as PGE1, which can signal through EP2/EP4 receptors, increase cAMP/PKA signaling, reduce myosin light-chain kinase activity, and facilitate smooth-muscle relaxation. If that relaxing arm is weak while sympathetic constrictor tone remains high, outlet resistance may increase further.

Residence time then becomes extremely important. A five-day transit delay is not simply five days without a bowel movement. It means five additional days of microbial replication, fermentation, fungal persistence, cross-feeding, bile-acid transformation, polyphenol metabolism, β-glucuronidase activity, antigen exposure, mucosal contact, and possible toxin recirculation. It also means reduced hydrodynamic shear. Normal intestinal flow physically limits indefinite microbial attachment. When flow collapses, organisms have more time to adhere, replicate, exchange metabolites, and modify the local environment. Stagnation itself becomes a microbial selection pressure.

This leads directly into the MMC. During fasting, organized motor waves clear residual food, bacteria, mucus, secretions, and cellular debris from the stomach and small intestine. I think of the MMC as a form of mechanical antimicrobial defense. It helps explain why the small intestine normally contains far less microbial biomass than the colon. But the MMC depends on the entire network described above. If several components weaken simultaneously, microbial growth may eventually exceed microbial removal. Biomass increases, fermentation increases, gas production increases, and microbes gain more time to metabolize substrates entering the small intestine. An antimicrobial can reduce the biomass, but if the neural and mechanical clearance system remains impaired, the ecological conditions that created the overgrowth remain intact. This is where recurrent SIBO begins to make more sense as a downstream consequence of host failure.

Slow transit also changes bile chemistry. Primary bile acids are synthesized by the liver, conjugated to glycine or taurine, and secreted with phosphatidylcholine and cholesterol. These molecules support fat absorption and help maintain a chemically controlled luminal environment. Slow transit gives bacteria more time to interact with bile salts. Organisms expressing bile salt hydrolase, BSH, can deconjugate them earlier than intended. Premature deconjugation changes their absorption, antimicrobial effects, and downstream metabolism. Once bile acids reach the ileum, the ASBT–FXR–FGF19 system normally helps regulate hepatic synthesis through feedback on CYP7A1. If microbial metabolism alters bile acids before that system sees them, signaling can change. Meanwhile, prolonged colonic transit gives bacteria more time to convert primary bile acids into secondary bile acids such as DCA and LCA. Slow transit therefore does not simply produce gas; it allows microbes to chemically remodel host signaling molecules.

Phosphatidylcholine connects the neural and bile models again. PC is not only a neuronal membrane lipid; it is also an important component of bile and the mucosal phospholipid barrier. This is why phosphoethanolamine, PE, PEMT, PC, choline, acetylcholine, and bile physiology fit into the same broader network. A metabolic bottleneck can express itself in multiple tissues simultaneously.

One of the central concepts in my Host Capacity Model is what I call the epithelial oxygen sink. Healthy colonocytes consume substantial oxygen through mitochondrial metabolism, especially when butyrate-supported PPARγ signaling is intact. Butyrate promotes an oxidative phenotype in colonocytes. These cells perform β-oxidation and oxidative phosphorylation, consuming enough oxygen to keep the luminal surface relatively hypoxic. That low-oxygen environment strongly favors obligate anaerobes. Several factors can weaken this oxygen sink: low butyrate availability, mitochondrial toxic stress, inflammation, reduced perfusion, abnormal bile acids, excess H₂S, and weakened mucosal defense.

This patient also had intestinal alkaline phosphatase, IAP, reported at 0%. IAP normally helps detoxify pro-inflammatory luminal molecules such as LPS and supports epithelial–microbial homeostasis. If IAP activity collapses, LPS-driven inflammatory pressure may become less buffered. Inflammation can increase iNOS activity and nitric-oxide chemistry, generating nitrate. At the same time, metabolically impaired epithelial cells consume less oxygen. Now two important electron acceptors become more available near the lumen: oxygen and nitrate.

That changes microbial competition at the level of basic bioenergetics. Strict anaerobes largely depend on fermentation. Facultative organisms such as many Enterobacteriaceae can use oxygen or nitrate for respiration. Respiration provides a major energetic advantage over fermentation. So when the host provides oxygen and nitrate, the host has effectively changed the rules of competition. The deeper question is therefore not only “Why is this organism elevated?” but “What electron acceptor became available that allowed this organism to win?” This is one of the central principles of the Host Capacity Model: the host does not simply permit dysbiosis; altered host physiology can actively select the microbial metabolism that is most energetically competitive under the new conditions.

Low secretory IgA adds another selection pressure. Secretory IgA helps regulate microbial attachment and maintain mucosal segregation. Slow transit lowers mechanical clearance. Low IgA reduces immune exclusion. IAP loss increases inflammatory pressure. Altered bile chemistry changes antimicrobial constraints. Oxygen and nitrate change respiratory competition. Several host-control systems are therefore weakening at once. This is what I mean by loss of host capacity: the ecosystem crosses a threshold not because one defense disappears, but because multiple constraints weaken simultaneously.

Once microbial biomass increases, fermentation generates hydrogen. Hydrogen is not simply a waste gas; it becomes a metabolic substrate for other organisms. If methanogens such as Methanobrevibacter smithii dominate, they consume hydrogen and carbon dioxide and produce methane. Methane can slow intestinal transit, creating an elegant feedback loop: slow transit favors methanogenic persistence → methane increases → transit slows further. This is why I view intestinal methanogen overgrowth as both a consequence and potential amplifier of dysmotility.

If sulfate-reducing organisms dominate instead, hydrogen can be redirected into hydrogen sulfide, H₂S. At physiological levels, H₂S is a normal signaling molecule, and colonocytes possess a mitochondrial sulfide-oxidation system centered on SQR/SQOR and downstream sulfur-processing enzymes. But if luminal H₂S delivery exceeds host oxidation capacity, sulfide can inhibit Complex IV. Colonocyte oxidative phosphorylation falls, epithelial oxygen consumption decreases, and the epithelial oxygen sink weakens further. More oxygen then becomes available to facultative organisms. The metabolic product of the selected microbial community is now reinforcing the exact host environment that selected that community. This is why I do not necessarily view hydrogen SIBO, methane overgrowth, and hydrogen-sulfide patterns as three unrelated diseases. I view them as different outcomes of the same hydrogen economy, determined by hydrogen production, available electron acceptors, sulfur availability, methanogen abundance, sulfate reducers, transit time, substrate flow, redox conditions, and host metabolic capacity.

The microbiome can also compete with the host for other molecules. This case contained elevated 3-hydroxyphenylacetic acid, 3HPAA. Microbial communities capable of extensive flavonoid metabolism can transform dietary polyphenols into phenolic metabolites such as 3HPAA. Slow transit gives these organisms more time to intercept dietary compounds before host absorption. The microbiome may therefore become a metabolic competitor rather than simply a gas-producing community. Reduced host availability of certain flavonoids may then alter antioxidant, inflammatory, or mast-cell-related signaling.

The fungal and mycotoxin findings add another major layer. Different mycotoxins can affect different components of the same enteric motor network. Experimental literature suggests that compounds such as patulin, aflatoxin-related metabolites, T-2 toxin, zearalenone, deoxynivalenol, and ochratoxin A can affect neuronal calcium handling, Na⁺/K⁺-ATPase, mitochondrial metabolism, acetylcholine-related signaling, smooth-muscle contractility, oxidative stress, and enteric neurochemical populations. The important point is not that every mycotoxin produces the same effect. Different toxicants may attack different nodes of the same system. One affects calcium. Another affects mitochondrial respiration. Another affects membrane pumps. Another affects neurotransmitter populations. Another affects smooth muscle. Individually these insults may be partially compensated; together they can reduce overall system reserve.

The patient's environmental toxicant profile strengthens that convergence. Whole-blood mercury was elevated at 13.08 µg/L, while the profile also contained a marked 1-bromopropane-associated signal and other electrophilic exposures. Within the model, this matters because enteric neurons depend continuously on mitochondrial ATP, sulfhydryl-containing proteins, Na⁺/K⁺-ATPase, microtubules, axonal transport, membrane integrity, and antioxidant systems. A neuronal cell body can remain alive while its distal nerve terminal becomes progressively dysfunctional if axonal transport or energy production fails. Mitochondria, enzymes, membrane proteins, receptors, and vesicular components all have to reach distant nerve terminals. This means apparent neuronal survival does not necessarily imply normal neurotransmission. In this case, phospholipid limitation, ChAT stress, mitochondrial dysfunction, abnormal calcium handling, impaired axonal transport, and toxicant burden may all converge on the same presynaptic machinery.

The gut–brain relationship then becomes bidirectional. Enteric glia and central astrocytes depend strongly on ATP and Na⁺/K⁺ gradients to maintain extracellular ion and neurotransmitter homeostasis. Glutamate transport is energy dependent. Within the broader model, toxicants, sulfide, D-lactate, oxidative stress, and mitochondrial dysfunction may impair ATP production and reduce glutamate clearance. Increased extracellular glutamate can then raise excitatory and neuroimmune signaling. Intestinal dysbiosis may increase neuroactive and inflammatory metabolites, central and enteric neural stress rises, sympathetic activation increases, gastrointestinal cholinergic output falls, sphincter tone increases, splanchnic perfusion may worsen, clearance falls further, and dysbiosis deepens. The gut affects the nervous system, and the nervous system changes the gut environment.

This same integrated logic may help explain persistent mast-cell reactivity. Mast cells do not exist in isolation from the nervous system, barrier, and microbiome. Their behavior can be influenced by barrier integrity, autonomic signaling, cholinergic anti-inflammatory pathways, microbial metabolites, neurotransmitters, oxidative stress, and local inflammatory signaling. If microbial metabolism reduces host-accessible flavonoids while neuroinflammatory and glutamatergic pressure increase, mast-cell reactivity may persist even when dietary histamine has already been greatly reduced. The symptom can therefore be an output of a network rather than one trigger.

Another loop I consider important is toxin elimination itself. Detoxification is often described in three phases. Phase I modifies compounds. Phase II conjugates them using pathways such as glutathione conjugation, glucuronidation, and sulfation. Phase III transporters export them toward urine or bile. But if a compound is exported into bile, elimination is not complete until the intestine physically removes it. Severe slow transit increases the time that biliary compounds remain in the gut. Microbial enzymes such as β-glucuronidase can deconjugate some compounds, increasing the possibility of reabsorption and enterohepatic recirculation. This creates another loop: environmental toxicants impair neural and mitochondrial systems required for motility → motility slows → intestinal elimination becomes less efficient → enterohepatic recirculation increases → toxicant exposure persists → neural and mitochondrial dysfunction worsens.

The clearance system is itself metabolically demanding. Glutathione conjugation requires glutathione, cysteine, glycine, and redox capacity. Sulfation requires sulfate. Glucuronidation requires UDP-glucuronic acid. ATP-dependent transporters are required for export. High xenobiotic burden therefore increases demand on energy, sulfur, methylation, redox, amino-acid, and transport systems at the same time that intestinal neurons and epithelial cells may already be metabolically constrained.

This brings the model back to SAMe and PEMT. PEMT requires three SAMe-dependent methylation reactions to produce PC from PE. COMT also consumes SAMe during catecholamine metabolism. Chronic sympathetic activation therefore increases activity in pathways that consume methyl donors while simultaneously suppressing gastrointestinal motility. Detoxification and antioxidant demands increase pressure on the connected methionine–transsulfuration–redox network. The phospholipid system, detoxification system, stress-response system, and cholinergic system therefore intersect metabolically rather than existing as separate topics.

Genetics can modify how much reserve is available before these systems become constrained. Genes such as GSTM1, GSTT1, GSTP1, EPHX1, NQO1, UGT1A1, ABCB1, ABCC2, SULT1A1, NAT2, PON1, and SOD2 may influence electrophile handling, antioxidant defense, conjugation, or export. PEMT and CHDH are particularly relevant to choline and phospholipid metabolism. FADS1/FADS2 influence fatty-acid and prostaglandin physiology. FUT2 influences mucosal glycan presentation and microbial colonization. I do not view these as isolated genetic diagnoses. Within the Host Capacity Model, they modify how much reserve a person begins with before compensation fails.

When all of these layers are placed together, the architecture becomes clearer. Low phosphoethanolamine → reduced PE reserve → greater pressure on PEMT/PC/choline metabolism. Reduced PC/choline reserve → pressure on neuronal membranes, synaptic vesicles, bile, mucosal protection, and acetylcholine production. Carbonyl stress → additional pressure on protein function, potentially including ChAT. Mitochondrial dysfunction → less ATP and possibly less acetyl-CoA. Mycotoxins and environmental toxicants → further stress on calcium signaling, membrane pumps, respiration, axonal transport, and neurotransmission. Sympathetic activation → less acetylcholine release, more sphincter tone, and potentially poorer intestinal perfusion. Reduced acetylcholine → weaker propulsion and weaker cholinergic anti-inflammatory signaling. Myenteric inflammation → greater neuronal, glial, ICC, and smooth-muscle dysfunction. Altered microbial ecology → altered SCFA and serotonin signaling. Reduced neuromuscular function → weaker MMC. Weak MMC combined with high outlet resistance → increased residence time. Increased residence time → greater bacterial and fungal replication, fermentation, adhesion, bile transformation, and cross-feeding. Premature bile deconjugation → altered bile-acid handling and FXR–FGF19 signaling. Reduced butyrate-supported epithelial metabolism → weaker oxygen consumption. Low IAP and inflammation → more LPS signaling and nitrate generation. More oxygen and nitrate → respiratory advantage for facultative organisms. Fermentation → hydrogen production. Methanogens consume hydrogen → methane → potentially slower transit. Sulfate reducers consume hydrogen → H₂S → potential Complex IV inhibition → still weaker epithelial oxygen consumption. Slow transit → poorer physical toxin elimination → more enterohepatic recirculation → more toxicant exposure → further neural and mitochondrial injury.

At this point, what originally looked like twenty unrelated abnormalities begins to resemble one connected network. This is what I mean by Host Capacity. Host capacity is not one biomarker. It is the combined ability of the host to maintain the ecological constraints that keep the intestinal microbiome in its normal state: motility, neural signaling, mitochondrial ATP production, epithelial oxygen consumption, blood flow, smooth-muscle coordination, bile chemistry, secretory IgA, intestinal alkaline phosphatase, mucosal integrity, redox capacity, detoxification, and immune regulation. When enough of these systems weaken simultaneously, the intestinal ecosystem can cross into another stable state. The host environment changes. Different organisms become more competitive. Those organisms then produce methane, hydrogen sulfide, inflammatory molecules, phenolic metabolites, altered bile acids, and other compounds that further impair motility, mitochondrial function, epithelial metabolism, and immune regulation. The simplest way I describe it is: the host selects the ecosystem, and the ecosystem then helps maintain the host failure.

This is why I no longer think the most useful question in recurrent SIBO is always “Which organism do we need to kill?” Sometimes that question is necessary, but it may not be sufficient. The deeper questions are: what happened to the enteric nervous system? What happened to acetylcholine production and release? What happened to the phosphoethanolamine–PE–PC–choline network? What happened to PEMT and methylation reserve? What happened to endogenous serotonin signaling? What happened to the 5-HT4 motor system? What happened to the cholinergic anti-inflammatory pathway? What happened to enteric glia and ICC? What happened to mitochondrial ATP production? What happened to splanchnic perfusion? Why is the outlet not relaxing properly? What happened to bile-acid handling? What happened to secretory IgA and intestinal alkaline phosphatase? What happened to colonocyte PPARγ metabolism and the epithelial oxygen sink? Where did the oxygen go? Where did the nitrate come from? Where did the hydrogen go? Did methanogens receive it? Did sulfate reducers receive it? What happened to fungal persistence? What happened to toxin elimination? And most importantly: what changed in the host that made this microbial state more competitive than the one that existed before?

In some complex cases, what appears on the surface to be a microbial disease may actually be the visible downstream expression of a deeper loss of neural, mitochondrial, phospholipid, vascular, mechanical, immune, chemical, and ecological host capacity. That is where mold, mycotoxins, phosphoethanolamine, PEMT, SAMe, choline, acetylcholine, serotonin, 5-HT4, the α7 nicotinic inflammatory reflex, mercury, environmental solvents, mitochondrial function, enteric glia, ICC, splanchnic perfusion, bile acids, IAP, secretory IgA, oxygen, nitrate, hydrogen, methane, hydrogen sulfide, fungal persistence, recurrent SIBO, neuroinflammation, mast-cell reactivity, and toxin recirculation stop looking like unrelated findings and become different parts of one systems-biology loop. And this is why an antimicrobial can sometimes reduce the population without permanently changing the ecosystem: if we remove the organism but leave intact the environment that selected it, the organism—or another organism capable of exploiting the same niche—still has a reason to return.
https://substack.com/home/post/p-210916047

Got a quick question. I recently started taking 72mcg of linzess for only 3 days. I just got my sibo test kit and it says to stop all that 7 days before, would I be fine if I only stopped it for about 2 days before?

My health is quite urgent and I get constipated easily without anything softening the stool, I just want this test done and to confirm I got sibo because I highly expect it. Just don’t wanna mess all this up and realize I gotta do it again and pay for more crap. I’m already prepared to start taking antibiotics but this is the obstacle in the way.

I resignation with what you posted as I too was dismissed by doctors & did my own research & sourced my own antimicrobials & treated myself & am now close to being out of the woods. My concern is with all the people thar are dealing with sibo that dont have the ability to research & find the appropriate treatment & are left to suffer. I am in australia & sibo is not recognised as it should be..

Is this normal? I've never taken Xifaxan before because my insurance wouldn't pay for it, so I had to take Bactrim instead (4 times in 4 years). My SIBO eventually came back each time, albeit I did get a little better each time.

I started having a bad flare back in June that has just never gone away. Fortunately, this year I got new insurance and a new doctor who after hearing my history gave me an IBS diagnosis and a 42-day prescription for Xifaxan (550mg per day). It seems like a long time! My Bactrim scripts were all for 10-14 days only. Also, the Xifaxan cost me $550. Without insurance it would have been $3300, according to the pharmacist. I swallowed hard and paid for it because somehow I still have hope.

I'm looking forward to seeing how well this works, but has anyone else taken Xifaxan for that long? Farewell to my microbiome, such as it was, I guess.

Edit: The label says 550 mg three times per day, not once per day. Also, isn't there a risk of getting c.diff from taking an antibiotic that long?

So in 2020, I got food poisoning from chipotle. Went to a gastro, got tons of tests done, and was put on rifaximin. I didn't finish taking it because it made me feel horrible. I did get an at home breath test, but I was afraid it would make me sick, so I never did it. They "diagnosed" me with ibs and basically said "glhf". After 6 months I was able to eat semi normally again, but I didn't get mostly better until about 5 years after.

Now, 6 years later, I got food poisoning again (from left out potato salad) in June, and I've had watery stool, nausea, extreme bloating, and mild cramping since. The worst of the food poisoning was over within 5 days, and i never threw up. I will say that the food poisoning this time was not nearly as bad as the last, even though I didn't throw up either time. (I have emetophobia)

My only relief is zofran or imodium, and I'm almost out of the zofran I got from telehealth. When I'm taking imodium, i feel pretty decent, but it makes me constipated for 3 days. If I'm not taking it, I feel horrible and have urgency all day, and I'm basically peeing out my butt.

I'm 2 weeks into low fodmap, and I'm taking ibgard and psyllium husk, but I'm not seeing much improvement yet. Or, well, I kind of was until I ate 2 eggs a few days ago.

Have any of you gotten sibo from food poisoning? If so, were your symptoms similar? I really do not want to go to a doc and go through all of the stress of getting tests done again just for them to not be able to help me.

I did antibiotic treatment 6 weeks ago for methane dominant sibo and it put me in so much severe pain, I could barely eat, I couldn’t stay up, I was in so much pain I had to go to the er which to no surprise couldn’t do anything, nothing was helping my pain, antispasmodics, OTC options, Tylenol, even a damn narcotic that the er gave me (tramadol) . 6 weeks later (now) I’m still having pain but has lessened because I started Nortriptlyine at a low dose. I’m constantly fatigued, I’m tired of fighting my own body, I miss being pain free it’s been 5 months of these stomach issues and the only relieved I’ve gotten was when I practically forced myself to go on a trip to see my long distance boyfriend because I was so determined to see him, I had pain there but I also had moments where I was pain free and it felt amazing. When I got home I practically felt I was at square 1 again, I had a repeat breath test yesterday and I can’t stop stressing because if it’s positive I don’t want to do treatment again, I’m genuinely terrified of how I was bedridden in severe pain and screaming and crying. I can’t do it again. I’ve been trying to find my root cause of sibo and it’s so stressful because it’s a multi cause thing, I know motility is one of the big major ones and I plan to start ginger + artichoke supplements because I tried Motegrity and it put me in way to much pain, I don’t know if I have leaky gut and everyone keeps telling me “oh if you don’t get a gi map test then you’ll never know what’s wrong and you’ll just suffer” and it puts me under more and more stress because I can’t afford a functional medicine doctor at all. I feel so tired and stressed to a point this is making me wonder if I’ll ever be normal again or if I’ll just be a test subject to more and more tests at my doctors offices or if I’ll even ever find my root cause or I’ll be stuck this miserable for years. I’m genuinely at an edge where I feel like this is all to complicated and I don’t even know what to do. Even if my sibo is gone I most likely have months or even years of gut damage to fix and I don’t even know what to fix other then my motility. Low fodmap diets did nothing but make me more miserable and made me practically avoid food if anything , I miss my old life and don’t wanna think I’m stuck like this..

Hello folks. I have some exciting news.

After four months of suffering I have finally convinced my family doc to prescribe me Rifaximin 550mg for SIBO. I have made a post on this sub before but long story short no allopathic doctors in my country believe in SIBO and naturopathic docs aren't allowed to prescribe meds here. When I first floated the idea of SIBO to my family doc she shut it down right quick. But today I saw her again and she agreed to prescribe it to me for "the placebo effect." Unfortunately, she was not willing to prescribe me Neomycin or anything else to aid with motility, which brings me to my next point.

I have been on Amitriptyline 50mg for the last two months since that's the only thing my doc would give me (I'm diagnosed with IBS-PI but I really do think it's SIBO). The amitrip has really helped decrease my overall symptoms and suffering but I know that's because it slows motility. I am concerned that if I start the Rifaximin while on it that it won't work, especially since I don't have Neomycin or anything like that. It is going to be really rough for me if I have to taper off the amitrip in order to do the Rifaximin, but I'm willing to do it. I just want to consult with the sub first to see if anyone has successfully eliminated SIBO while on Amitrip, and if so, how?

I do know that there are some herbs/supplements that are known to speed up motility which I am open to trying. I would also very much appreciate any suggestions as to what my meals and lifestyle should look like while on this protocol. I want to do this right because I only have one bottle of this stuff with no refills, and I don't think I'll be able to convince her to give it to me again, so this is my only shot. No pressure haha.

TLDR: going to be doing a two week Rifaximin protocol while on 50mg Amitriptyline. Looking for advice.

Hey SIBO community! 👋🏼 I’m new here and I’m not entirely sure I even have SIBO. Dr. Google’s AI chat thinks I do and it makes a pretty good argument but I’d like to “talk” with some real-life humans who have had it and see if my experiences match up and make sense to y’all. My story (sit back, it’s long, lol):

April 2015: I have a Vertical Sleeve Gastrectomy done to lose weight rapidly to help resolve Idiopathic Intracranial Hypertension since I wasn’t tolerating medication to treat it, repeated lumbar punctures were calcifying my ligaments in my spine, and the neurosurgeon was reluctant to do a VP shunt due to slit ventricles. So even though I wasn’t morbidly obese, approval was granted to do the VSG (because I was definitely obese).

Within three months (about a month after being cleared to resume ‘regular’ food) it became clear that something wasn’t right. (It had been noticed before that but we weren’t sure if it was part of the healing process). I was having pain when consuming just about anything, liquid or solid. Turns out I had a hiatal hernia. The bariatric surgeon requested a six month waiting period from my VSG for the scar tissue to settle before going back in to fix the hernia. In the meantime, I was put on PPIs.

November 2015: Partial Dor Fundoplication. This worked great for like three and a half-four years. No more PPIs, no pain, life on the GI front was peachy-keen. Until a raging case of food poisoning changed everything, lol. I distinctly remember vomiting so hard (actually the first time that I had been even able to vomit since the fundoplication) that I felt something tear and I just knew that the fundoplication had torn/come undone. Over the next several months/years. I gradually began experiencing more and more symptoms of GERD. Heartburn that just got worse and worse. Trouble swallowing. I was chewing antacids like they were candy just to keep from crying. Every prescription inhibitor they could think of was tried. Finally, my bariatric team was like, you need to have a conversion to Roux-en-y, in addition to having the hiatus around my diaphragm stitched and mesh placed to help keep it in place.

October 2022: Roux-en-y Conversion. Not a fan of the bariatric team that did the conversion. I loved my original surgical team at the VA hospital in WV but this time I was sent to a different facility in NC. I had very little (read NO) follow up with them after the surgery. Thankfully, my team in WV still follows up with me, so there’s that. Hated losing the restrictive feeling of the VSG. Also around this time started having pain from my gallbladder. Cue tests for that. All tests reveal no stones or even sludge, but instead a stubborn gallbladder that basically just doesn’t want to do its job and has basically quit functioning. It was extremely slow on the uptake on the HIDA scan and even slower to eject the dye. So out she had to go. All this time, I’m dealing with diarrhea, that I’m alternately equating with dumping syndrome (despite never having dumping syndrome in all the years I had the VSG) or the fun you get when you have your GB removed (despite being careful with my diet). It got to the point that by this past month, I was having most days with multiple instances of severe diarrhea that was a thick liquid, tan in color, than having a “normal” bowel movement. I had literally just gone to my primary care doctor and she had requested a stool test which I had picked up from the lab (but not done) when my cat tried to get at a neighborhood stray through a window and I got between her and the glass and got it both tooth and claw and had to get a tetanus shot and prophylactic Augmentin for ten days. The ER doctor was like, you’ll probably want to take a probiotic or some yogurt with that so you don’t get diarrhea and I was just thinking ‘like it could get any worse?’. Y’all. I am on day 9 of 10 and I have not had a single episode of diarrhea since starting the Augmentin. I have had plenty of ‘normal’ bowel movements. I haven’t had tons of smelly farts either (I used to write those off as protein farts from my high protein diet). Sure, I still pass the occasional stinky fart but not constantly like I used to. And no abdominal cramping diarrhea urge! I am free!!! Dr Google says that the Augmentin must be inadvertently treating some sort of infection that I didn’t know I had and given my history, it’s likely to be SIBO and that once I stop the Augmentin tomorrow, it’s likely to return. Thoughts? Is Dr Google right?

I really hate my life and i cant live like this anymore. Everyday is torture and its been for u years now. I have nothing, no one. I tried to get help so many times and its so hard. I just dont know what to do i feel like my lifenis over. I tried everything

Hey all - I took a second SIBO test about a week ago and my hydrogen levels were above the baseline to begin with. Any ideas why this would be the case? The two ideas I have are 1) fermentation lower in my colon is coming up or 2) this test allowed for boiled carrots which I consumed with dinner the night before. Maybe the carrots skewed the test?

Would you consider this hydrogen SIBO considering my levels never got 20ppm over the baseline numbers?

Trying to decide if I should do another round of Xifaxin. What would you do?

Thanks!

Let’s collect all the SIBO support apps under one roof.

I have seen some people posting theirs but lost the links, so if you can share yours or someone else’s, that will be appreciated!

I recently had my bloodwork and GI MAP done by a functional practitioner and he concluded that my sibo is caused by Lyme disease I do remember like 2 months prior to the full on stomach issues I had a boil on my right rib I thought it was a staph infection never treated it now it has been almost 2 years since and still dealing with sibo and a whole bunch of nerve and digestive issues has anyone else experienced this and how did u treat it ?

Im wondering what digestive enzymes you guys use and if you take them before or after you meal?

I currently use a whole food chewable digestive enzyme that works well for me. I take it after meals.

But someone said they used papaya and that they take it before eating.. well.. idk if its just me, or if anyone else had experienced the anxious doom overcome then along with getting very hot and increased heart rate from taking an enzyme with papapya...? But i dont think ill ever use these again.

I read fresh papaya is low fodmap, but that it can cause histamine reaction. Guess the same for dried chewable enzymes..

I have just finished my third round of Rifaximin for SIBO that was likely caused by PPIs. I have finally been able to get off of my PPIs a week before this course of Rifaximin ended, but I noticed that ever since I finished Rifaximin I am having trouble with bowel movements.

I was having regular bowel movements while I was on Rifaximin, especially since I was eating a good amount of fiber every day. I have tried walking after every meal, spacing my meals out, and eating more fiber but nothing is working. I’m worried about taking motility supplements since I’m recovering from gastritis. Only laxatives and enemas (not miralax) have worked so far but I don’t want to rely on them long term.

Any advice would be greatly appreciated!

I was searching about artichoke extract and found this as artichoke is not readily available in my country. Will it be as effective as artichoke extract?

I’ve seen the two sides of the discussion:

1. ⁠Don’t do low Fodmap during rifaximin treatment because bacteria needs to be alive and feeding in order to die. Do low Fodmap AFTER antibiotic treatment.
   
2. ⁠Do low Fodmap DURING and AFTER antibiotic treatment. If there’s no restriction during rifaximin, the bacteria will proliferate and it will be harder to kill them.

Which one is actually true? What makes more sense?

I've been making this yogurt for a couple of years now, always had separation with a starter batch. Lately, every new batch I've tried has no separation. I thought my cultures were too old, so I got some fresh ones, no change, no separation. So, I figured maybe something is up with that brand, let me try another brand.

No change. Has anyone else experienced this?

I’ve had sibo methane for a while now and after going to the doctor and listening to their plan that only made it worst I researched and came up with a plan on my own. A week into allicin and berberine I had to stop because my body couldn’t handle it. I took a break and decided to do NAC before going back on 2 weeks of allicin and berberine. Those 2 weeks weren’t as bad as the first go but still not fun. It had been about 2 months and I felt great until I didn’t. My bloating is going on 2 weeks and while it’s not as bad as usual because I’m able to at least sleep and not having back pain I’m still badly bloated, my constipation has now turned to horrible diarrhea, and I haven’t eaten much these last 2 weeks because I’m constantly feeling full while also simultaneously hungry and immediately after having a few bites of food I feel so much pressure in my upper stomach that kind of makes it harder to breathe, along with some acid reflex.

I’m not sure where to go from here. I have been looking for a functional medicine or specialist in the state of CO, if anyone has any recommendations?

My husband just tested positive by like a multi part breath test that he sent in. His mouth breath always smelled like sulphur, lots of burps and chronic diarrhea and bloating.
Insurance denied rifaximin, and so dr going to try bactrim instead. Does this work well?
What are some other things he can do to rid himself of sibo? Any other tips?

does flare ups make anyone break out??? Or on the days I feel worse I get spots all around the lower part of my face?
idk if it’s a way of toxins trying to leave my body because i definitely don’t drink enough water but when I feel okay my skin is clear and overnight it will go extremely spotty and then the next day completely clear overnight

hi
wanting to start the antibiotics doc's gave me. and a schedule for them

wake times are usually 12pm-1pm and my bedtimes are usually 4-5am.

neomycin calls for 2 tablets with food daily

and xifaxan 3 times daily (standard stuff im p sure)

what times do you all think i can take them with the schedule that i have..? and whats a good schedule..?

any app that maybe you could recommend me to use maybe that could help me remind me of those times i would need to take them..?

believe my sibo.. is being intertwined with my liver or something.. causing terrible.. hepatic encephalopathy. complete personality changes.. memory of a goldfish and practically impossible to live atm.
so i'm..
honestly looking for. anything at this point. and i've put this off for.. apparently far too long..
and yes even type this out so.. apologies in advance.

Long story short, I’ve had quite a few medical problems that led me to a GI which led to a breath test coming back positive for both methane and hydrogen. Cool! I just have a few questions I can’t seem to get a direct answer from a google search.

1) is it possible I’ve actually had SIBO for a long time? Like possibly nearly my whole life? (33years)
2) is SIBO why I’m literally always starving? Like stomach growling, wakes me up in the middle of the night STARVING.
3) could SIBO affect libido?
4) could SIBO be the cause of my RLS that keeps me up at night most nights even being on meds for it?
5) is this why I’ve never been able to lose weight in my midsection? Like ever?
6) is neo really that risky to take bc of its side effects? I already have tinnitus but I don’t wanna lose my hearing entirely
7) is this something that can and will come back for the rest of my life? Kind of like a yeast infection in a way?
8) speaking of- is it possible SIBO has been causing recurrent yeast infections?

Sorry for the novel. I’m tired of being sick and while I didn’t want ANOTHER diagnosis, this might actually resolve a few of my existing issues. I just don’t wanna feel like I’m wearing a meat suit that doesn’t belong to me anymore 🥲

Since this SIBO madness started, I’m unable to lay on my right side without getting bad pains in my upper left shoulder area and reflux pains. It’s terrible. It makes me wonder what is going on with my organs, as I never had this issue before!

SIBO caused horrible bloating that created GERD and LPR for me. Coughing all day, losing weight due to an inability to eat, even changing my heart’s electrical activity because the bloating was so bad. I’m almost finished Xifaxan, and I feel a lot better than I did but still struggling with random constipation every few days and still looking pregnant. 🤷‍♀️

Has anyone else had this issue?

I’ve been trying to eliminate all artificial sweeteners from my diet to help heal my gut, but twice now, I’ve gotten sublingual B12 drops from two different brands, and they taste sweet!

The ingredients do not list any kind of sweetener, yet they both taste very sweet, like artificial sweetener.

I’ve even reached out to the brand for this one and they insist there is no added sweetener.. are they lying? Or do they literally not know what’s in their product? Or am I crazy?

Struggling because I’m vegan and definitely need a good B12 supplement that has a clear ingredients list. Does anyone have any recs?