Why Dysbiosis, SIBO, Hydrogen Sulfide Intolerance, MCAS, and Long COVID May All Be Downstream of a Single Event — The oxia-dysbiosis loop: the engine that turns a small failure into a chronic disease

Now we can describe the central mechanism of chronic gut dysfunction — the self-reinforcing cycle I call the oxia-dysbiosis loop. Picture what happens when the colonocyte's mitochondria start to fail — from inflammation, infection, toxin exposure, viral reactivation, nutrient depletion, or any of the redox insults we'll come to in a moment. A struggling cell can't run oxidative phosphorylation (the oxygen-hungry, butyrate-burning pathway) efficiently anymore. So it does what stressed cells do: it falls back on glycolysis — generating ATP from glucose without needing much oxygen. This is sometimes called a Warburg-like shift, after the same metabolic switch seen in cancer cells. Here is the catch. A glycolytic colonocyte consumes far less oxygen. And the moment epithelial oxygen consumption falls, the vacuum cleaner shuts off. Oxygen — and, via inflammation-driven iNOS, nitrate — begins to leak into the lumen. Watch the dominoes fall: oxygen leaks into the niche, and the obligate anaerobes (the good guys) lose their competitive advantage because oxygen is poison to them. Facultative anaerobes and oxygen-tolerant organisms — Enterobacteriaceae, the inflammatory pathobionts — surge in to fill the space, now respiring on the leaked oxygen and nitrate. (Rivera-Chávez and colleagues showed in 2016 that simply depleting butyrate-producing Clostridia is enough to oxygenate the gut and