May 20, 2012
Spectacular news for the 14 million Americans living today with a diagnosis of cancer: this week, two impressive medical studies show that exercise helps to prevent recurrence of cancer. The first study of 45 peer-reviewed articles published from January 1950 to August 2011 shows that exercisers are less likely to die of their cancers than non-exercisers. Also, 27 observational studies strongly showed that exercise is associated with reduced death from breast and colon cancers specifically (J Natl Cancer Inst, published online May 8, 2012). Those who exercised were also less likely to die from other diseases such as heart attacks.
The second study, from the Netherlands, showed that cancer survivors who exercised had far more energy, were far more active, and were less tired than survivors who did not exercise. Exercising gave them more energy (PLoS One, published online May 2, 2012)
CANCER CELLS ARE DIFFERENT FROM NORMAL CELLS. Every normal cell in your body has programmed into its genetic material, a process called APOPTOSIS, that lets it live and multiply only so long and then it dies. For example, skin cells live 28 days and then die; cells lining your mouth live 24-48 hours; and red blood cells live up to 120 days. Cancer cells lose their ability to die. They try to live forever and they kill by going from one type of tissue to invade and destroy another type of tissue. For example, breast cancer cells can eventually spread to your brain or lungs. They replace and destroy these tissues, and you die because your brain or lungs are not able to work properly.
Cancer cells grow and multiply so rapidly that they need huge amounts of the sugar, glucose, to supply them with the energy necessary for growth. Let me explain why cancer cells need so much sugar.
HOW ALL CELLS GET ENERGY: All cells get their energy from two major processes:
• glycolysis, and
• the Krebs Cycle.
Normal cells primarily use the Krebs Cycle for energy since it is more efficient and provides more energy. However, cancer cells do not use the Krebs Cycle well, and therefore must depend on glycolysis. Because they use this inefficient pathway for energy, cancer cells that have forgotten to die have an incredible increase in need for energy from the sugar, glucose. Since insulin drives sugar into cells, insulin and ILGF-1 (insulin-like growth factor-1) feed cancer cells glucose, encouraging them to grow and multiply.
CANCER CELLS USE GLYCOLYSIS: In the early 1920s, Otto Warburg demonstrated that cancer cells can live without oxygen by getting their energy from glycolysis. Since glycolysis uses the single sugar, glucose, for energy, cancer cells use tremendous amounts of glucose to grow. Since cancer cells depend on glucose for energy, anything that interferes with the body’s normal use of glucose supplies more sugar to the growing cancer cells, which will increase growth of an existing cancer and risk for new cancers. This is one of the reasons why diabetes and excess weight increase risk for cancer.
MITOCHONDRIA: In every cell there are from a few to hundreds of small organelles called mitochondria. They provide energy for cells through the Krebs Cycle, which is far more efficient than glycolysis, the process that supplies energy inside cells but outside the mitochondria. All cells need functioning mitochondria, where the Krebs Cycle occurs, to have apoptosis. Cancer cells have defective mitochondria which forces them to use glycolysis for energy. Since cancer cells have defective mitochondria, and do not use the Krebs cycle effectively, they do not have apoptosis, so they live indefinitely and kill by invading and destroying normal cells.
EVERYTHING THAT RAISES BLOOD SUGAR LEVELS INCREASES CANCER RISK: being overweight, not exercising, being diabetic or pre-diabetic, eating sugar or refined carbohydrates when you are not exercising, lack of vitamin D, not having enough muscle, storing fat primarily in your belly, and so forth.
A CURE FOR CANCER? Researchers today are trying to cure cancer by blocking glycolysis. This could force mitochondria to become active again and use the Krebs Cycle for energy so that the cells can stop being cancerous and regain apoptosis, their programmable cell death. The chemical dichloroacetic acid (DCA), which increases the chemical reactions of the Krebs cycle in mitochondria, has been shown to kill cancer cells in laboratory tests and in animals. Anything that activates or restores mitochondria can restart apoptosis and cause cancer cells to kill themselves. At the University of Alberta, Dr. Evangelos Michelakis is doing research on DCA. Another activator of mitochondria, 3- BrOP, is being studied at The University of Texas M. D. Anderson Cancer Center. 2-deoxyglucose (2-DG) is being used at Emory University School of Medicine, and lactate dehydrogenase A is being researched at Johns Hopkins University.
YOU CANNOT CURE CANCER BY PREVENTING ALL CELLS FROM USING SUGAR. You cannot prevent or cure cancer just by avoiding sugar. All carbohydrates are made up of chains of sugars, and the only known way to deprive your body of sugar is to starve yourself to death. Sugar will always be available. The researchers’ goal is to prevent sugar from entering cancer cells.
WHAT WOULD HAPPEN IF CANCER CELLS WERE UNABLE TO OBTAIN SUGAR? A possible cure for cancer was presented by Philipp Mergenthaler and Andreas Meisel, of Charité-Universitätsmedizin Berlin, Germany, and McMaster University, Canada. They showed that depriving a cell of the sugar, glucose, while giving it plenty of oxygen at the same time, blocks glycolysis and therefore forces the cell to revive its mitochondria and use the Krebs Cycle for energy. Reviving the mitochondria also revives apoptosis, the process of programmed cell death, and therefore would stop cancer cells from growing and spreading through the body (Proceedings of the National Academy of Sciences of the USA, January 2012).
HOW EXERCISE GROWS MITOCHONDRIA AND HELPS TO PREVENT CANCER: Today, the only proven way to grow new mitochondria and enlarge existing ones is to exercise. The more vigorously you exercise, the greater the growth in size and number of mitochondria. Cancer cells have defective mitochondria and therefore have to use glycolysis (sugar) primarily for energy. Reviving the mitochondria shifts the primary energy use to the Krebs Cycle. This would revive apoptosis to make cancer cells die normally.