Cancer metabolism

Cancer metabolism is a state of impaired respiration in which cells regress to a primitive form of energy production, aerobic glycolysis, even in the presence of oxygen. 2 Otto Warburg discovered this in 1923, observing that cancer cells produce large amounts of lactic acid rather than oxidizing glucose fully to carbon dioxide, a failure of the Pasteur effect where respiration normally suppresses fermentation. 2 Peat argued that this is not a genetic defect but a basic adaptive survival process, a metabolic condition triggered when anything—carcinogens, radiation, or prolonged oxygen deprivation—interferes with oxidative metabolism. 2 The cell, facing an energy crisis, dedifferentiates and reverts to glycolysis, a less efficient pathway that extracts far less energy from fuel and produces lactic acid as a waste product. 7

The shift to cancer metabolism is driven by a systemic energetic failure characterized by excessive stimulation and substrate depletion. When cells are dangerously overstimulated, oxygen and glucose become depleted, forcing the conversion of glucose to lactate; when glucose is exhausted, glutamine is converted to lactate. 4 This creates a reductive stress state, an electron-rich, pseudohypoxic condition that blocks the enzyme pyruvate dehydrogenase and further inhibits glucose oxidation. 4 Peat described how increased cortisol activates the Randle effect, shifting the organism toward the oxidation of fat and protein rather than glucose, while also activating fatty acid synthase to produce fatty acids from amino acids and pyruvate in a "futile cycle" that liberates ammonia, which further suppresses respiration and stimulates glycolysis. 1 The flooding of the body with free fatty acids, particularly polyunsaturated fatty acids, amplifies inflammatory-carcinogenic processes and produces resistance to thyroid, insulin, and cortisol. 2

At the cellular level, the metabolic derangement involves a fundamental disruption of electron flow. Szent-Györgyi conceptualized the difference between the primitive and differentiated states as a matter of electron acceptors: in cancer, pyruvic acid acts as the electron acceptor, forming lactic acid, whereas in healthy oxidative metabolism, oxygen serves as the far more powerful terminal electron acceptor, enabling a higher-voltage energy flow. 7 Dinkov has extended this framing, explaining that excessive fatty acid oxidation blocks electron transport chain complex II via depletion of flavin adenine dinucleotide (FAD), causing a buildup of electrons that the cell resolves by jettisoning its energetically expensive oxidative machinery and reverting to glycolysis. 9 The cancer cell then compensates for its inefficient energy production by massively upregulating glucose transporters, not because it is "addicted" to sugar, but because it perceives a lack of glucose due to its failure to oxidize it properly. 9

This metabolic state is self-reinforcing and systemic. Lactic acid itself is an irritant that increases the expression of hypoxia-inducible factor (HIF), which in turn causes cells to depend even more on converting glucose to lactic acid. 6 The cancer cell attempts to drain away the excess electrons generated by this reductive imbalance by synthesizing fat, then oxidizing that fat with whatever oxygen is available—a process that is less efficient regarding oxygen use and deepens the oxygen deficiency. 8 Peat emphasized that sugar deprivation, such as ketosis, actually turns on the Warburg effect and the stress reaction, worsening the condition. 8 He identified progesterone as a substance that affects all features of cancer metabolism in the right way, while noting that promoters like histamine, serotonin, and muscarinic cholinergic signals have safe antagonists that are underutilized. 3 Aging itself involves a metabolic shift in the direction of cancer metabolism, with increased fat oxidation, decreased glucose oxidation, and a progressive inability to fully restore the high-energy resting state of cells. 4