Inflammatory bowel disease is not a single disease, and it is not, at its mechanistic root, an autoimmune disease in the conventional sense. The clinical labels Crohn's disease and ulcerative colitis describe distinct anatomic and histologic patterns of intestinal inflammation, but at the cellular level both conditions are dominated by a specific failure: the colonocyte's loss of bioenergetic capacity, particularly its ability to oxidize butyrate, which collapses the gut oxygen gradient, restructures the microbial community toward inflammatory phenotypes, breaches the mucosal barrier, and recruits the sustained immune response that the immunosuppressive medications target. The medications quiet the response. They do not restore the colonocyte. This is why remission is so often partial, why response to biologics is lost over time, and why approximately half of all Crohn's patients experience post-operative recurrence within twelve months of surgery. The mechanism standard treatment is missing has been described in the primary literature since 1990. It is finally beginning to be named.

The clinical pattern that defines treatment-resistant IBD

A patient presents to a gastroenterologist with bloody diarrhea, abdominal pain, weight loss, urgency, and fatigue. Colonoscopy reveals continuous mucosal inflammation of the colon (ulcerative colitis) or discontinuous transmural inflammation that may involve any portion of the gastrointestinal tract (Crohn's disease). The patient is started on an aminosalicylate (5-ASA) for mild-to-moderate disease, or a corticosteroid for active flare, or a biologic (anti-TNF agents like infliximab and adalimumab, anti-integrin agents like vedolizumab, anti-IL-12/23 agents like ustekinumab, or the newer JAK inhibitors and S1P modulators) for moderate-to-severe disease.

Many patients respond. The inflammation reduces. The bleeding stops. The bowel movements normalize. The patient enters clinical remission. For some, this remission is sustained. For many, it is partial. For a substantial fraction, the response is lost over time. The literature documents primary non-response rates of approximately 30 percent for biologics and secondary loss of response rates of approximately 40 to 50 percent over five years of follow-up. Post-operative recurrence in Crohn's disease is approximately 50 percent within twelve months of ileocolic resection, even when the macroscopic disease has been entirely removed.

The standard interpretation of these patterns is that IBD is a relapsing-remitting immune-mediated disease, that some patients have more aggressive phenotypes than others, and that the variable response reflects the heterogeneity of the underlying immunology. The clinical task becomes finding the right combination and sequence of immunosuppressive agents for each patient.

The alternative interpretation, which the primary research now supports, is that the variable response reflects something more specific. The immunosuppressive medications target the downstream inflammatory response. They do not address the upstream lesion that is producing the response. The lesion is in the colonocyte itself. Until the colonocyte is restored, the inflammatory signal that the medications suppress continues to be generated. The medications can hold the line for a period. Eventually the upstream signal exceeds the suppressive capacity of the medication, or the cell adapts to the medication, or the side effect profile becomes intolerable, and the cycle resumes.

This article describes the upstream lesion and its implications for what a more durable approach to IBD looks like.

What Roediger discovered in 1990 and why it matters

In 1990, the Lancet published a paper by William Roediger titled "The colonic epithelium in ulcerative colitis: an energy-deficiency disease?" The paper made a specific claim. Colonocytes from patients with ulcerative colitis have reduced capacity to oxidize butyrate compared to colonocytes from healthy controls. The reduction is substantial. Roediger called UC an "energy-deficiency disease" of the colonic epithelium.

The paper was largely ignored by the mainstream gastroenterology research community for the following two decades. The field was committed to an immunologic framing of IBD, in which abnormal immune response to luminal contents was the central lesion. The colonocyte bioenergetic angle was relegated to a footnote.

Subsequent research has supported and extended Roediger's finding. Studies by Donohoe and colleagues, Bäumler and colleagues, Litvak and colleagues, and others have documented that colonocyte mitochondrial dysfunction is present in active IBD, that the dysfunction is mechanistically connected to the loss of obligate anaerobic core taxa, that the resulting shift in luminal oxygen tension allows facultative anaerobes (Enterobacteriaceae and others) to expand, and that this expansion is itself inflammatory. The complete story is now well-characterized in the primary literature. It has not yet propagated into clinical practice.

The mechanism is this. The healthy colonocyte derives approximately 70 to 80 percent of its energy from butyrate oxidation. Butyrate is produced by the obligate anaerobic core of the gut microbiome, particularly Faecalibacterium prausnitzii, Roseburia intestinalis, and members of the Lachnospiraceae and Ruminococcaceae families. The colonocyte transports butyrate across its apical membrane, oxidizes it in the mitochondrion, generates ATP, and consumes oxygen at the surface of the epithelium. This oxygen consumption maintains physiological hypoxia at the mucosal surface, which preserves the niche that the obligate anaerobic core depends upon.

When the colonocyte loses its capacity to oxidize butyrate, several things happen in sequence. ATP output falls. Oxygen consumption falls. Luminal oxygen rises. The obligate anaerobic core loses its competitive advantage. Facultative anaerobes (E. coli, Klebsiella, and other Enterobacteriaceae) expand into the newly-aerobic niche. Butyrate production falls because the producing taxa have been displaced. The mucus layer thins because Akkermansia muciniphila, which depends on the healthy mucus environment, has been displaced. The barrier function weakens. Bacterial products translocate. The immune system, encountering bacterial products in tissue that should be sterile, mounts an inflammatory response.

This is the lesion that produces IBD. The inflammation is downstream. The immune response is the readout. The lesion is in the cell that lost its capacity to do its job.

The specific mechanisms producing colonocyte bioenergetic failure in IBD

Several specific mechanisms produce the colonocyte bioenergetic failure that drives IBD. They overlap. Most IBD patients have features of all of them.

The SLC5A8 epigenetic silencing pathway

SLC5A8 is the principal apical transporter for butyrate uptake into the colonocyte. It is epigenetically regulated. Its promoter is methylated under conditions of chronic mucosal inflammation, and the methylation silences the transporter. Multiple studies have documented SLC5A8 silencing in colorectal cancer, where the silencing is particularly well-characterized. The same silencing occurs in IBD, where it produces a functional decoupling: butyrate is present in the lumen but cannot enter the cell.

This explains a clinical paradox. Butyrate supplementation, which has been studied extensively as a potential IBD treatment, produces inconsistent results across patients. Some respond. Many do not. Stool butyrate levels may correlate poorly with clinical response. The current explanation in the functional medicine literature is variable bioavailability or formulation issues. The more parsimonious explanation, supported by the SLC5A8 research, is that butyrate cannot enter cells whose transporter has been silenced. The substrate is present. The transporter is not. The functional outcome is the same as if the substrate were absent.

This same mechanism is described in the recurrent SIBO article and connects to broader colonocyte dysfunction patterns. In IBD, the SLC5A8 silencing is particularly pronounced in actively inflamed regions and partially reverses in quiescent disease, though the reversal is incomplete.

Iron-sulfur cluster damage

Mitochondrial oxidation depends on iron-sulfur cluster proteins. Complex I contains eight Fe-S clusters. Complex II contains three. The Rieske protein in Complex III is an Fe-S protein. Aconitase, succinate dehydrogenase, and several other TCA cycle and electron transport enzymes are Fe-S proteins. The entire oxidative machinery rests on dozens of Fe-S clusters that are continuously damaged and continuously rebuilt.

Under inflammatory conditions, the damage rate accelerates and the rebuild rate slows. The principal damaging species is peroxynitrite, produced from the combination of nitric oxide and superoxide that accumulates during sustained inflammation. The principal limit on rebuild is substrate availability (cysteine, iron, NAD+) and intact machinery (frataxin, NFS1, ISCU). Both are compromised in IBD.

The consequence is a colonocyte that, even if SLC5A8 is intact, cannot dispose of the reducing equivalents generated by butyrate oxidation because the electron transport chain is operating below capacity. The TCA cycle backs up. The cell shifts toward glycolysis. ATP output falls. Oxygen consumption falls. The luminal oxygen rises.

In IBD, the Fe-S damage is one of the central mechanisms producing the energy-deficiency state that Roediger described, though Roediger did not have the molecular vocabulary to name it in 1990.

The CD38-NAD+-SIRT3 cascade

The third mechanism operates at the regulatory layer. SIRT3 is the dominant mitochondrial deacetylase. It maintains the deacetylated state of dozens of mitochondrial enzymes, including long-chain acyl-CoA dehydrogenase (controlling fatty acid oxidation), succinate dehydrogenase (Complex II), and manganese superoxide dismutase (mitochondrial antioxidant defense). When SIRT3 activity falls, hyperacetylated enzymes accumulate. The mitochondrial proteome shifts toward its less-functional state.

SIRT3 activity depends on NAD+. In states of sustained inflammation, CD38 expression rises sharply. CD38 is an NAD+ glycohydrolase whose catalytic turnover dwarfs that of the sirtuins. When CD38 dominates NAD+ metabolism, the NAD+ pool collapses, and SIRT3 activity falls proportionally.

In IBD, the CD38 induction is driven by the local mucosal inflammation, by translocated bacterial products that signal through innate immune receptors, and in some cases by post-viral immune activation that preceded the IBD onset. The mechanism connects IBD bioenergetically to chronic fatigue, brain fog, and post-viral illness, which is why IBD patients so often have systemic symptoms that the gastroenterology framing does not address. See the article on why labs come back normal for the full cascade.

Hydrogen sulfide and Complex IV inhibition

In ulcerative colitis particularly, the displaced microbial community often becomes dominated by sulfate-reducing taxa, particularly Desulfovibrio piger and Bilophila wadsworthia. These taxa produce hydrogen sulfide as a metabolic byproduct. At sustained high concentrations, H2S inhibits cytochrome c oxidase, Complex IV of the electron transport chain. The colonocyte that was already struggling to oxidize butyrate now also cannot perform terminal electron transport at full capacity.

The H2S Complex IV story is particularly relevant to ulcerative colitis, where elevated sulfate-reducing bacteria are a consistent finding. The clinical pattern of UC flare often correlates with H2S burden. Anecdotal but consistent clinical reports describe patients whose UC flares improve substantially with bismuth subsalicylate, which precipitates sulfide and reduces local H2S concentrations. The mechanism is not yet formalized in clinical guidelines but is consistent with the Complex IV story.

Why this mechanism explains the clinical patterns better than the standard model

The standard immunologic model of IBD predicts that immunosuppression should produce durable remission, that response should be relatively predictable, and that surgical removal of diseased tissue should be curative for Crohn's disease (which involves discrete segments) and for ulcerative colitis (where colectomy removes the entire involved organ).

The data do not support these predictions. Approximately 30 percent of patients do not respond to first-line biologics. Approximately 40 to 50 percent lose response over five years. Post-operative recurrence in Crohn's disease occurs in approximately 50 percent of cases within twelve months despite complete resection of all macroscopically diseased tissue. Pouchitis develops in approximately 50 percent of UC patients after restorative proctocolectomy with ileal pouch-anal anastomosis. These are not the patterns predicted by a model that locates the lesion in a specific tissue or in a specific immune circuit.

These are the patterns predicted by a model that locates the lesion in the bioenergetic state of the surviving epithelium. When surgery removes the diseased segment, the remaining epithelium often shares the same bioenergetic compromise. The post-surgical anastomosis recurs because the new epithelial surface adjacent to the resection is still the bioenergetically compromised tissue that produced the original disease. The pouch becomes pouchitis because the small intestinal epithelium adapting to colonic functions is now exposed to luminal contents under the same bioenergetic limitations that produced the original colitis.

This is also why response to biologics is lost over time. The biologic suppresses the inflammatory response. It does not restore the cell. The signal that drives the inflammation continues to be generated. Over time the suppressive capacity of the medication is exceeded, the inflammatory phenotype escapes, and the disease resurges.

This is not a failure of the medications. The medications do what they are designed to do. They suppress the immune response. The framework is incomplete because it does not include the upstream lesion. Adding the upstream framing does not require abandoning the medications. It requires understanding that the medications are containment while the upstream work is addressed in parallel.

What the microbiome looks like in IBD

The microbial signature of IBD is one of the most consistent findings in the literature. Specific taxa are reliably depleted. Specific taxa are reliably expanded.

Depleted in IBD: Faecalibacterium prausnitzii, the dominant butyrate producer in the healthy gut, falls dramatically. The depletion correlates with disease severity and predicts flare risk. Roseburia intestinalis and other butyrate producers in the Lachnospiraceae family are similarly depleted. Akkermansia muciniphila, the dominant mucus-resident commensal, is reduced or absent. Overall microbial diversity is reduced — alpha diversity metrics consistently show lower values in active IBD compared to healthy controls.

Expanded in IBD: Enterobacteriaceae (E. coli, Klebsiella) expand, often substantially. Specific adherent-invasive E. coli strains have been identified in Crohn's disease and may contribute to pathogenesis. Sulfate-reducing taxa (Desulfovibrio, Bilophila) often expand in ulcerative colitis. Fusobacterium has been associated with both IBD and colorectal cancer. Several Candida species, particularly Candida albicans, expand in some patients.

This microbial pattern is not a primary cause of IBD. It is the predictable consequence of the colonocyte bioenergetic failure. The taxa that depend on physiological hypoxia (the obligate anaerobic core) are displaced when the hypoxia is lost. The taxa that thrive in the resulting aerobic conditions (the facultative anaerobes) expand. The taxa that produce inflammatory metabolites in this context (sulfate-reducers producing H2S, Enterobacteriaceae producing LPS) contribute to the sustained inflammatory state.

Fecal microbiota transplantation (FMT) for IBD has produced mixed results in clinical trials. Some patients respond. Many do not. The variable response is consistent with the bioenergetic framing: transplanting the healthy microbial community into a colon whose epithelium has lost its bioenergetic capacity does not produce durable colonization, because the host substrate cannot sustain the niche that the donor community depends upon. The microbes reshape themselves around the conditions the compromised host is producing. This is why repeat FMT often loses effect over time, and why FMT is more effective in conditions where the host substrate is intact (recurrent Clostridium difficile infection, for example) than in conditions where it is not (IBD).

What restoration looks like

A treatment approach that addresses the bioenergetic lesion alongside the conventional medical management of IBD looks substantially different from standard care. The conventional medications remain appropriate for the inflammation. The bioenergetic work proceeds in parallel.

The bioenergetic work, in rough sequence:

First, identify and reduce the upstream drivers sustaining the inflammatory drive. This is patient-specific. For some it is dietary triggers (specifically food antigens crossing a compromised barrier). For some it is ongoing low-grade infection. For some it is environmental exposures, including mycotoxins. For some it is bidirectional vagal dysfunction described in the POTS article. The patient's specific drivers need to be identified through systematic case review.

Second, restore the regulatory cofactor pool. NAD+ precursor supplementation (nicotinamide riboside or NMN at clinically validated doses, often combined with niacinamide as a baseline support) addresses the CD38-driven NAD+ depletion. Attention to methylation cofactors supports the broader cofactor environment. B vitamins in their functional forms. Magnesium glycinate. The cofactor work is foundational because without it the cell cannot perform the work the other interventions require.

Third, work the colonocyte substrate directly. This includes addressing the SLC5A8 silencing where possible (through reducing the inflammatory drive that produced it), supporting Fe-S cluster biogenesis (through substrate availability and reduction of damage), and supporting the recolonization of the obligate anaerobic core community (through resistant starch, prebiotic fibers as tolerated, and in some cases targeted probiotics with documented colonization). The substrate work proceeds slowly. The epigenetic processes that need to reverse operate on a timescale of months.

Fourth, address the autonomic and immune regulation. The cholinergic anti-inflammatory pathway, vagal tone restoration, sleep architecture, stress regulation. These are not optional. They are part of the upstream regulatory environment that determines whether the substrate work can hold.

Fifth, manage symptoms with containment as the upstream work proceeds. The biologic continues. The mesalamine continues. The corticosteroid taper proceeds as the gastroenterologist directs. Symptomatic care is not in conflict with mechanistic care. They are layers operating at different points of the cascade.

The full sequence operates on the timescale of six to eighteen months for substantial mechanistic improvement. The clinical inflammation response may be faster, particularly as the upstream work reduces the signal that the medications are suppressing. Some patients experience medication reduction over time as the upstream work proceeds, under their gastroenterologist's supervision. The goal is not to come off the medications. The goal is to address the upstream lesion so that, over time, the medications are doing less work and the cell is doing more.

This is the approach a Biomelogic consultation works through

The deliverable is a written mechanistic analysis that places the IBD case in HCM terms, identifies the dominant upstream drivers in the specific patient, and recommends sequencing for the patient's existing clinical team to implement alongside the conventional medical management. Biomelogic does not prescribe, does not modify biologic dosing, and does not replace the gastroenterologist's role. The work is educational systems-biology analysis delivered in coordination with the IBD specialist managing the case. IBD patients have a more clearly-defined need for ongoing specialist medical care than many other chronic illness presentations, and the framework explicitly operates alongside that care, not instead of it.

Frequently asked questions about Crohn's disease and ulcerative colitis

Is IBD curable?

Cure is the wrong framing. Most IBD patients will continue to manage the condition over their lifetime. The clinically useful framing is durable remission, where the disease is quiescent, medications are at their lowest effective dose, and the patient is functioning normally. Bioenergetic restoration extends the durability of remission and reduces the rate of relapse. It does not eliminate the underlying susceptibility, which has substantial genetic contributions in many cases.

Can I come off my biologic?

That is a decision made with your gastroenterologist, not with Biomelogic. The Host Capacity Model framework is not a strategy for stopping medication. It is a strategy for addressing the upstream lesion so that the medications do less work over time. Some patients, with their gastroenterologist's supervision, reduce medication dosing as the upstream work proceeds. Others remain on their current regimen indefinitely. The medication decision is medical care and belongs with the medical clinician.

Is the Host Capacity Model recognized by IBD specialists?

Not yet in this specific form. The colonocyte bioenergetic angle is increasingly recognized in the primary research literature, particularly in the work of Bäumler, Litvak, Donohoe, and others. The Roediger 1990 paper is finally being cited more frequently. The integration of these findings into a clinical framework that operates alongside conventional IBD care is the novel work. It is being developed and tested through case experience and ongoing collaboration with academic partners.

Does the framework apply to Crohn's disease as much as to ulcerative colitis?

The colonocyte bioenergetic mechanism is more directly established for ulcerative colitis, which by definition involves the colonic epithelium. Crohn's disease can affect any part of the GI tract, and the relevant epithelial bioenergetics differ by anatomic location. The CD38-NAD+-SIRT3 cascade, the Fe-S cluster damage, and the broader inflammatory-bioenergetic story apply to both. The specific intervention sequencing differs by location and phenotype.

Why does my Crohn's keep recurring after surgery?

This is the post-operative recurrence pattern described above. Surgery removes the macroscopically diseased tissue. It does not address the bioenergetic state of the surviving tissue. The new anastomosis is composed of epithelium that often shares the same bioenergetic compromise as the resected segment. Without addressing the upstream lesion, the new tissue often develops the same disease pattern over the following months. This is why post-operative Crohn's recurrence is so common despite the apparent completeness of the surgical intervention.

Should I take butyrate supplements for my IBD?

The decision is between you and your clinical team. The Host Capacity Model perspective is that butyrate supplementation can be helpful in patients whose SLC5A8 transporter is intact and whose Fe-S cluster machinery can oxidize the additional substrate. In patients whose SLC5A8 is silenced or whose Fe-S clusters are damaged, the supplementation may produce inconsistent results. The clinical pattern of inconsistent butyrate response, well-documented in the IBD literature, is consistent with this framing. Some patients benefit substantially. Others do not. The framework helps identify which patients are which.

What about diet?

Diet matters substantially in IBD but the right diet varies by patient. The specific carbohydrate diet, the IBD-AID diet, the Mediterranean diet variants, the low-FODMAP approach, and the carnivore diet have all shown benefit in some patients and not in others. The pattern is consistent with the framework: the right diet is the one that reduces the inflammatory drive for the specific patient while supplying the substrate that the patient's intact colonocytes can use. This is highly individualized work that benefits from systematic case review.

Is Mohammed Attallah a doctor?

No. Mohammed Attallah is an independent systems-biology researcher and developer of the Host Capacity Model. He is not a licensed clinician. Biomelogic provides educational systems-biology analysis that operates alongside the client's existing licensed medical team, particularly the gastroenterologist managing the IBD. IBD requires ongoing specialist medical care and the framework does not replace that care.

What does a Biomelogic consultation cost?

The Standard Consultation is $650 one time, which includes the case review, the live session, and the written mechanistic analysis. The full service menu is at biomelogic.net/services. HSA and FSA eligibility varies.

How do I get started?

The lowest-friction starting point is the free 15-minute discovery call. The call determines whether the case is a fit. If yes, the next step is the Standard Consultation. If not, the call ends with a referral to a more appropriate resource. For IBD specifically, the framework is most useful for patients who have an established gastroenterology relationship and who are seeking mechanistic understanding to inform that relationship, not to replace it.

Working with Biomelogic on Crohn's disease or ulcerative colitis

If the patterns described above resonate with the IBD case you have been navigating, a Biomelogic consultation may be useful. The work is appropriate for patients with an established gastroenterology relationship, who are interested in understanding the mechanistic layer that conventional IBD care does not address, and who are willing to do the slow upstream work alongside the medical management.

The lowest-friction starting point is the free 15-minute discovery call. The call is not medical advice and not a sales pitch. It exists to determine whether the framework is appropriate for the case. If it is, the next step is the Standard Consultation. If it is not, the call ends with a recommendation of where to look instead.

For patients ready to proceed directly to a full case workup, the Gate 1 intake form is the starting point.

For readers wanting the deeper framework, The Host Capacity Model is the canonical framework page.

Related articles

Selected primary research

The mechanisms described in this article are drawn from primary research published over the past three decades. Key references include:

  • Roediger WEW. The colonic epithelium in ulcerative colitis: an energy-deficiency disease? Lancet. 1980;2(8197):712-715.
  • Donohoe DR, Garge N, Zhang X, et al. The microbiome and butyrate regulate energy metabolism and autophagy in the mammalian colon. Cell Metabolism. 2011;13(5):517-526.
  • Litvak Y, Byndloss MX, Tsolis RM, Bäumler AJ. Dysbiotic Proteobacteria expansion: a microbial signature of epithelial dysfunction. Curr Opin Microbiol. 2017;39:1-6.
  • Sokol H, Pigneur B, Watterlot L, et al. Faecalibacterium prausnitzii is an anti-inflammatory commensal bacterium identified by gut microbiota analysis of Crohn disease patients. Proc Natl Acad Sci USA. 2008;105(43):16731-16736.
  • Khor B, Gardet A, Xavier RJ. Genetics and pathogenesis of inflammatory bowel disease. Nature. 2011;474(7351):307-317.

These references are starting points. The literature on colonocyte bioenergetics and IBD has expanded substantially in the past decade. The framework described in this article synthesizes findings across this literature into a clinical interpretation that has not yet been formalized in mainstream gastroenterology practice.