METABOLIC CROWDING
High levels of deuterium causes metabolic crowding as important metabolic biological thresholds are affected, namely proton/hydrogen harvesting and water recycling from the hydratases in the TCA cycle. Protons can no longer get into the mitochondrial matrix and hydrogens pile up outside of mitochondria and lactic acids also accumulate. This is why pyruvate converts to lactic acid, even in the presence of oxygen. This is the Warburg effect.