CANCER AND OXYGEN

Cancer cells are anaerobic

Growth of cancer cells is initiated by a relative lack of oxygen known as cellular hypoxia. This process cannot begin or continue in an oxygen rich environment.

In the February, l956, issue of Science, pp. 309-3l4, Dr. Otto Warburg, reported that all cancer cells produce excessive or inordinate amounts of lactic acid and all have impaired  mitochondria. These are compartments in all cells that house the Krebs cycle. Approximately 70 percent of the total energy needs of the body are derived from the Krebs cycle.  Beyond this cycle a process called glycolysis contributes approximately 20 percent of the body’s total energy needs and the mono-phosphate shunt approximately l0 percent (taken from textbook Practical Physiological Chemistry). Living cells cannot grow, reproduce, or survive without sufficient amounts of energy to carry out their multitude of  metabolic functions.

It may be of interest to note here that the  Krebs cycle can extract energy from carbohydrates, fats, or amino acids. Glycolysis and the mono-phosphate shunt, however, extract energy only from glucose or carbohydrates. It is also important that the Krebs cycle and the mono-phosphate shunt require oxygen for their metabolic functions whereas glycolysis, whether in normal or cancerous cells, functions without oxygen or anaerobically.

When Dr. Warburg made his discoveries concerning the excessive production of lactic acid by cancer cells, little was known then about the thirteen enzymes that function in  the   Krebs cycle and the 11 enzymes that function in glycolysis. This is why neither he nor the cancer community  at that time realized the potential  therapeutic significance  of his lactic acid, mitochondria discoveries,  and the crucial role they could  play in  the treatment of all cancers.

Dr. Warburg found that normal cells derive most of their energy from respiration (aerobically or with the use of oxygen), whereas cancer cells derive most of their energy anaerobically or from fermentation (without the need of oxygen). This implies that normal cells derive most of their energy though the Krebs cycle (aerobically), whereas cancer cells derive most of their energy from glycolysis (anaerobically).

At the time, Dr. Warburg,  as well as the cancer community, all believed that cancer cells produce  large amounts of lactic acid only because they are deprived of sufficient oxygen to carry out their metabolic functions. The lack of knowledge then concerning the functions of the Krebs cycle and glycolysis,   thus prevented medical science from  understanding that cancer cells production of excessive lactic acid signifies that they rely  almost exclusively upon carbohydrates or glucose  for their major energy and that proper  dietary modification, such as a diet low in carbohydrates, can prove a viable adjunct to conventional medicine in the treatment of all cancers.

Studies recently reported by scientist’s working in both cancer and AIDS research now explain how cancer cells can produce inordinate amounts of lactic acid because of injury to their mitochondria, even in the presence of oxygen.

It has become known, for example, that the activities of the mono-phosphate shunt are increased more than ten-fold in cancer cells (Journal of the National Cancer Institute, Dec. 6, 2000, p. 1926), compared to normal cells. As mentioned above, the mono-phosphate shunt functions aerobically or with oxygen. This implies that if cancer cells were being deprived of oxygen, we would not find an increase in the activities of the  mono-phosphate shunt but  a reduction in activities instead.

At the time, Dr. Warburg could not see the immediate therapeutic potential of  his  discoveries. But the technology he developed allowed him to measure the amounts of oxygen cancer cells consumed and the amounts of lactic acid they produced. When he found that cancer cells were producing such large amounts of lactic acid and that their oxygen consumption was greatly reduced, he assumed this was all caused by an insufficient supply of oxygen. He did not know at the time that if the mitochondria were defective within cells, they could not use their Krebs cycle and that this would cause them to produce excess lactic acid even though the cells were not deficient in oxygen. 

In the December 3, l997, issue of the Journal of the National Cancer Institute, p l764, appears the following, “Most solid tumors rely almost exclusively on the anaerobic metabolism of glucose as their main energy source, with most being converted to lactate. Glucose uptake and lactate release by human colon carcinomas have been found to exceed the peripheral tissue exchange by 30-fold and 43-fold, respectively.” This implies that colon cancer cells burn 30 to 40 times more glucose for energy than normal cells.

Dr. Warburg reported in his l956 article that normal liver cells burn more than l00 times more oxygen than cancer cells. This implies that the normal cells derive most of their energy from the Krebs cycle and not from glycolysis, as is the case with cancer cells.

A  PET scan detects cancer cells, it identifies them by the amounts of glucose they consume. This is further evidence of the ravenous appetite cancer cells have for glucose.

Knowing that cancer cells require such large amounts of glucose to grow, reproduce, and  even to survive, placing cancer patients  on   a low carbohydrate diet not only  makes good sense  but also  good medicine.

Article on Oxygen and Cancer