Biomelogic
Flagship framework · Host Capacity Model

The Host Capacity Model

Recurrent gut dysfunction reflects failing host bioenergetic capacity, not a primary microbial disease.

  • ▸The microbial community tracks the habitat the host provides.
  • ▸When colonocyte ATP economy fails, oxygen, nitrate, and pH shift — and dysbiosis follows.
  • ▸Treating the host's capacity reorganizes the community downstream.
Core Insight
Microbial state tracks host capacity. The candidate upstream mechanism is bioenergetic.

Conceptual narrative

Conventional models place dysbiosis upstream and treat the microbe. The Host Capacity Model inverts that arrow: the lumen's anaerobic, low-nitrate, butyrate-fueled steady state is a host-maintained achievement of colonocyte mitochondrial throughput.

When that throughput collapses — from iron-sulfur cluster insufficiency, NAD+ depletion, mitochondrial oxidant stress — oxygen leaks luminally, nitrate accumulates, and the niche permits facultative anaerobe expansion. The clinical syndromes follow.

Mechanistic layers

  1. Substrate. Butyrate β-oxidation in the colonocyte sustains epithelial O2 consumption.
  2. Hinge. ATP throughput gates the oxygen and nitrate gradients that select the community.
  3. Downstream. Habitat shift → endotoxin/metabolite stress → immune & mast cell activation → systemic phenotype.
Foundational Mechanism
Colonocyte mitochondrial throughput maintains the epithelial oxygen sink that gates the entire community.
Host Capacity Model — causal mapMitochondrial throughputO₂ gradientHabitat / nicheNitrate availabilityCommunity stateBiomeLogic — Host Capacity Model
The Host Capacity Model — signature mechanistic diagram. BiomeLogic — Host Capacity Model.

Evidence map

  • establishedColonocyte O2 sink (Litvak/Bäumler). Hypoxia-driving role of colonocyte mitochondria is well characterized.
  • establishediNOS-nitrate / Enterobacteriaceae expansion. Documented mechanism in inflamed colon.
  • strong-mechanisticBioenergetic primacy across all chronic illness phenotypes. Coherent across multiple datasets; not a single trial.
Key Contradiction
Reductionist single-pathogen accounts of recurrent SIBO and post-viral gut illness fail to predict recurrence patterns the HCM accommodates.
Systems-Level Interpretation
Dysbiosis, MCAS, post-viral dysautonomia and recurrent SIBO are read as projections of a single bioenergetic axis onto distinct phenotypic surfaces.
Mechanistic Prediction
Restoring colonocyte ATP throughput should reorganize community structure within weeks, with microbial composition lagging functional recovery.
Conceptual Limitation
HCM does not address structural lesions, neoplasia, or genetic IEMs that operate outside the bioenergetic axis.

Canonical terminology

Host Capacity Model (HCM)
The Host Capacity Model (HCM) holds that recurrent SIBO, MCAS, post-viral illness, and persistent dysbiosis are downstream consequences of failing host bioenergetic capacity at the gut epithelium — not primary microbial diseases.
colonocyte bioenergetics
Colonocyte bioenergetics describes how colonic epithelial mitochondria oxidize butyrate to maintain steep epithelial oxygen consumption, sustaining the lumen's near-anaerobic state that selects for obligate anaerobic commensals.
oxygen-gradient failure
Oxygen-gradient failure is the collapse of the colonocyte-maintained oxygen sink, raising luminal pO2 and licensing facultative-anaerobe (Proteobacteria) blooms — a pivotal hinge in the Host Capacity Model.

FAQ

Is HCM a diagnostic system?

No. It is a mechanistic framework; it does not replace clinical diagnosis.

Does HCM dismiss the microbiome?

No. It reframes microbial state as a tracking variable of host capacity, not as a primary lesion.

Citation

Attallah, M. The Host Capacity Model. BiomeLogic, Host Capacity Model. https://biomelogic.net/flagship/host-capacity-model

Update timeline

  • — Flagship layout introduced.
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