Healthy and Unhealthy Cell Cycles
All of your cells need glucose (blood sugar) for energy. Healthy cells follow a life cycle of growth, division and death. Like leaves on a tree, old cells die off and are replaced by an equal number of healthy cells. Cancer develops when old cells refuse to die, but keep growing, dividing, and building up in one place – creating a tumor.
Cancer Loves Sugar – Truth or Rumor?
This familiar saying, "cancer loves sugar" has been around since the 1924 publication of Dr. Otto Warburg's paper, "On metabolism of tumors." Warburg was a Nobel Prize winning cell biologist who wrote, "Summarized in a few words, the prime cause of cancer is the replacement of the respiration of oxygen in normal body cells by a fermentation of sugar." Many people who referred to his work in later years misquoted Warburg's statement by saying, "cancer loves sugar."
Warburg's hypothesis stated that cancer growth was caused when cancer cells converted glucose into energy without using oxygen. Healthy cells make energy by converting pyruvate and oxygen. The pyruvate is oxidized within a healthy cell's mitochondria, and Warburg theorized that since cancer cells don't oxidize pyruvate, cancer must be considered a mitochondrial dysfunction.
Now that we know more about the genetics of cancer, we know that cancer is not a mitochondrial dysfunction, but is caused by genetic mutations, such as appear on the genes BRCA1 and BRCA2. It is true that healthy cells and cancer cells convert their food to energy in different ways, but that difference is an effect, and not a cause, of cancer.
Sugar and Proteins Keep Cancer Cells Alive
It's been said that cancer cells are immortal – they don't die off in an orderly way like healthy cells do. Scientists have studied this effect and may have discovered what tumor cells do to avoid cell death. In laboratory research at Duke University, cancer cells appear to use a combination of sugar and specific proteins to keep growing when they should die. These cancer cells appear to use sugar at a high rate, in order to ignore cellular instructions to die off. So might sugar – which appears to make cancer cells stronger – someday turn out to be cancer's Achilles' Heel?
Developing New Sugar-Coated Cancer Drugs
At Johns Hopkins University, a group of researchers looked at ways to fool cancer cells into growing more slowly and then eventually killing themselves. They studied abnormal glycosylation - how cancer cells put sugar and proteins together to sustain themselves. When these cells were given n-butyrate (a salt) with carbohydrates (contains sugar), cell proliferation slowed down. In order to feed the cancer a death-dealing drug, they produced a hybrid molecule made of a simple sugar and n-butyrate. Because the cancer cells absorbed the sugar readily, they soaked up this new molecule, which interfered with their ability to keep growing, and they died.
Other teams of scientists are working on drugs that will take advantage of cancer's weakness for sugar. Some of these new drugs may be given along with chemotherapy, to make tumor cells more sensitive to chemo drugs. In Switzerland, scientists are using a sugar coating on "quantum dots" or nanocrystals of drugs that would travel to the liver only, avoiding other organs. It's the sugar on those little doses that help the drugs target one particular part of the body, thereby reducing side effects and increasing the effects of the drugs.
Be Smart About Sugar in Your Diet
Sugar provides energy, but doesn't give you any nutrients that are needed to reduce your cancer risk. Natural sugars are in fruits and vegetables as well as honey and molasses – they should be part of a healthy diet. Processed sugars such as white or brown sugar and corn syrup should be avoided or limited. Consuming too many sugar calories can lead to obesity and high insulin levels, which would contribute to your increased cancer risk. Cut back on sugar-loaded foods such as candy, baked goods, sugary cereals and sodas to reduce your cancer risk. Balance your diet with plant foods, fish, and whole grains. Use white sugar sparingly and try natural sweeteners instead.
It's OK to eat some natural sugars on a daily basis. Sugar in your diet does not cause cancer to develop. Starving all of your cells of sugar won't kill or prevent cancer, but it will deprive your healthy cells of a necessary source of energy. Keeping a balance of nutritious foods and a regular exercise routine can give you a healthy body weight and normal insulin levels. That's the sweet way to reduce your cancer risk.
GSK-3α/β Mediate a Glucose-Sensitive Anti-Apoptotic Signaling Pathway to Stabilize Mcl-1. Zhao, Y., B.J. Altman, J.L. Coloff, C.E. Herman, S.R. Jacobs, H.L. Wieman, J.A. Wofford, L.N. Dimascio, O. Ilkayeva, A. Kelekar, T. Reya, and J.C. Rathmell. 2007. Mol Cell Biol. 27:4328-39.
Targeting Glycosylation Pathways and the Cell Cycle: Sugar-Dependent Activity of Butyrate-Carbohydrate Cancer Prodrugs. Srinivasa-Gopalan Sampathkumar, Mark B. Jones, M. Adam Meledeo, Christopher T. Campbell, Sean S. Choi, Kaoru Hida, Prasra Gomutputra, Anthony Sheh, Tim Gilmartin, Steven R. Head and Kevin J. Yarema. Chemistry & Biology, Volume 13, Issue 12, December 2006, Pages 1265-1275.
Nutrition and Physical Activity Guidelines for Cancer Prevention: Summary. American Cancer Society. Approved: May 19, 2006.
Prospective Study of Hyperglycemia and Cancer Risk. Pär Stattin, MD, PHD, Ove Björ, BSC, Pietro Ferrari, BSC, Annekatrin Lukanova, MD, PHD, Per Lenner, MD, PHD, Bernt Lindahl, MD, PHD, Göran Hallmans, MD, PHD and Rudolf Kaaks, PHD. Diabetes Care March 2007, Vol. 30 no. 3 561-567.
In Vitro Imaging and in Vivo Liver targeting with Carbohydrate Capped Quantum Dots. Journal of the American Chemical Society, February 18, 2009. Peter H. Seeberger.