Cancer as a metabolic disease

Is cancer a metabolic disease?

In principle, there are few chronic diseases more easily preventable than cancer.

Seyfried and Shelton 2010

A new and important article in Nutrition and Metabolism makes a case for cancer as predominately a metabolic disease. Research has shown that one of the key features of cancers is an impaired or damaged respiration. In fact, as the authors put it, “Aerobic glycolysis, arising from damaged respiration, is the single most common phenotype found in cancer.” Evidence is reviewed supporting a hypothesis that cancer is a disease of energy metabolism, primarily liked to mitochondrial function.

The hypothesis isn’t new. It was first proposed in the early twentieth century, but was soon displaced with the view of cancer as a genetic disease. Emerging evidence however, questions the genetic origin of cancer and suggests that cancer is primarily a metabolic disease. Damage to cellular respiration may easily precede and underlie the known genome instability associated with tumor development. Once genome instability is established, it increases and furthers respiratory impairment which increases mutation and tumor growth, and we’ve got ourselves a vicious cycle.

The article asks the question “Is it genomic instability or is it impaired energy metabolism that is primarily responsible for the origin of cancer?”

The question is of immense importance, as the answer will impact the way we view and treat cancer.

Dietary energy restriction has been used to lower glucose levels, thus reducing growth and progression of several tumor types, like mammary, brain, colon, pancreas, lung, and prostate cancers. Enhanced glycolysis (breakedown of glucose) is required for the rapid growth and survival of many tumor cells, and a treatment targeting cell metabolism will be of great importance.

A shift from glucose to ketone body and fatty acid use would be beneficial because it targets only cancer cells with their reliance on glycolysis, while being benign or even beneficial for normal cells. Not only do cancer cells rely heavily on glucose for fuel, but many do also have abnormalities in the genes and enzymes needed to metabolize ketone bodies for energy.

Despite making a case for a shift in metabolism from glucose to ketone body use, the authors do not make a case for low carbohydrate diets, but rather propose the use of energy restriction to cause a dietary ketosis.

Prostate and gastric cancer are manageable using low carbohydrate ketogenic diets, and these diets are far more efficient and safe for inducing dietary ketosis compared to general energy restriction. Metabolism of ketone bodies for energy can also maintain mitochondrial health and efficiency thus reducing the risk of cancer development.

From the conclusion: 

Two major conclusions emerge from the hypothesis; first that many cancers can regress if energy intake is restricted and, second, that many cancers can be prevented if energy intake is restricted. Consequently, energy restricted diets combined with drugs targeting glucose and glutamine can provide a rational strategy for the longer term management and prevention of most cancers.

Despite beating about the bush when it comes to carbohydrate restriction, this is recommended reading!

Article her: http://www.nutritionandmetabolism.com/content/7/1/7