The metabolic theory of cancer suggests that cancer is primarily a metabolic disease, meaning it arises from changes in cellular metabolism rather than solely from genetic mutations, which is the basis of the traditional genetic theory of cancer. This theory is grounded in the observation that cancer cells have unique metabolic needs and behaviors, especially related to how they produce energy.
In the 1920s, Otto Warburg observed that cancer cells prefer to generate energy through anaerobic fermentation, a process of breaking down glucose into lactate, even when oxygen is plentiful. This is different from normal cells, which use oxidative phosphorylation in the presence of oxygen for more efficient energy production.[1]
The Warburg effect indicates that cancer cells rely heavily on glucose (sugar) for energy, which has implications for dietary and therapeutic approaches.[2]
Proponents of the metabolic theory argue that mitochondrial dysfunction plays a crucial role in cancer. Mitochondria are the cell’s energy factories and play a role in regulating cell death (apoptosis).[3] When mitochondria are damaged or function abnormally, cells may not undergo proper apoptosis, leading to uncontrolled cell growth.[4]
Cancer cells often rely on glutamine as an alternative energy source and as a building block for growth, especially when glucose is limited.[5] This metabolic flexibility allows cancer cells to adapt and thrive in diverse environments, making them more resistant to standard treatments like chemotherapy.[6]
Dietary approaches: Low-carbohydrate or ketogenic diets are suggested as potentially helpful because they limit glucose availability to cancer cells, thereby "starving" them. These diets force the body to produce ketones, which cancer cells cannot easily use. Targeting metabolism in treatment: Drugs that disrupt cancer cells' metabolic processes, particularly those targeting glucose or glutamine metabolism, are being explored as cancer treatments.[7]
The metabolic theory is still under investigation and remains controversial. While there is evidence supporting the role of altered metabolism in cancer, the genetic mutation model also has significant support. Many researchers are now examining cancer as a complex interplay of genetic mutations and metabolic dysregulation, rather than a purely genetic or purely metabolic disease.[8] [9]