Patrick Quillin, PHD, RD, CNS, former director of nutrition for Cancer Treatment Centers of America in Tulsa, OK, wrote: “It puzzles me why the simple concept ‘sugar feeds cancer’ can be so dramatically overlooked as part of a comprehensive cancer treatment plan” (Nutrition Science News, April 2000). I agree. Sugar is cancer’s favorite food. There are at least five reasons that cancer and sugar are best friends.
Cancer cells love sugar! That is why refined carbohydrates like white sugar, white flour, high fructose corn syrup (HFCS) and soft drinks are extremely dangerous for anyone trying to prevent or reverse cancer.
How Does Sugar Cause Cancer Cells to Grow?
Sugar essentially feeds tumors and encourages cancer growth. Cancer cells uptake sugar at 10-12 times the rate of healthy cells. In fact, that is the basis of PET (positron emission tomography) scans — one of the most accurate tools for detecting cancer growth. PET scans use radioactively labeled glucose to detect sugar-hungry tumor cells. When patients drink the sugar water, it gets preferentially taken up into the cancer cells and they light up!
The Link Between Sugar and Tumors
The 1931 Nobel laureate in medicine, German Otto Warburg, PhD, discovered that cancer cells have a fundamentally different energy metabolism compared to healthy cells. He found that malignant tumors exhibit increased glycolysis — a process whereby glucose is used as a fuel by cancer — as compared with normal cells.
Warburg’s research also found that cancers thrive in an acidic environment. Sugar is highly acidic. With a pH of about 6.4, it is 10 times more acidic than the ideal alkaline pH of blood at 7.4. Maintaining a preventative pH level may require reducing or eliminating dietary sugar.
Sugar suppresses a key immune response known as phagocytosis – the Pac-Man effect of the immune system. Consuming 10 teaspoons of sugar can cause about a 50% reduction in phagocytosis.
If you consider the sugar in your cereal, the syrup on your waffles and pancakes, the sugar added to your morning coffee or tea, the sugar in cold beverages like iced tea or lemonade, the HFCS in prepared foods, salad dressing and ketchup, and of course sugary snacks and desserts, you can see how easy it is to suppress your immune systems significantly.
How Long Does Sugar Impact the Immune System?
Not only the amount of sugar, but also the frequency of ingesting sugar is relevant to immune function. In one study, research subjects were found to have nearly a 38% decrease in phagocytosis one hour after ingesting a moderate amount of sugar. Two hours later, the immune system was suppressed 44%; immune function did not recover completely for a full five hours.
In most people, when sugar in any form is consumed, the pancreas releases insulin. Breast tissue, for example, contains insulin receptors, and insulin is a powerful stimulant of cell growth. One group of Australian researchers concluded that high levels of insulin and insulin-like growth factor (IGF) may actually be causative of cancers of the breast, prostate, endometrium and pancreas.
Does Sugar Increase the Risk of Breast Cancer?
A broad study conducted in 21 countries in Europe, North America and Asia concluded that sugar intake is a strong risk factor contributing to higher breast cancer rates, particularly in older women. A four-year study at the National Institute of Public Health and Environmental Protection in the Netherlands compared 111 biliary tract cancer patients with 480 healthy controls. Sugar intake was associated with more than double the cancer risk.
Sugar ingestion seriously contributes to obesity, a known cause of cancer. Obesity also negatively affects survival. More than 100,000 cases of cancer each year are caused by excess body fat, according to the American Institute for Cancer Research. These include esophageal, pancreatic, kidney, gallbladder, breast and colorectal cancer.
Although I am against sugar, please don’t think I recommend artificial sugar substitutes! Sweeteners containing aspartame, saccharin or sucralose have been shown to contribute to bladder cancer, lymphoma and leukemia, according to the National Institute of Environmental
Good sugar substitutes are stevia (an all-natural herb from South America), barley malt, rice syrup, and palm sugar. Even high-glycemic sweeteners like Sucanat, evaporated cane juice, molasses, honey and pure maple syrup are nutritionally superior to refined table sugar or HFCS, and you can avoid sugar spiking if you consume them in the presence of high fiber foods like ground flaxseeds.
The Sugar and Cancer Connection
There is much evidence showing sugar is linked to cancer, but can sugar cause cancer? Research is still underway to determine if there is a direct causative connection or if sugar is a contributing factor only after cancer cells have developed. Certainly, we do know that sugar is bad for cancer prevention and treatment.
Controlling sugar intake will help create the best environment for a healthy immune response and prevent causative risk factors which are still being discovered. I hope this and the other posts from The Center for Advancement in Cancer Education will help guide you to a rapid recovery, future prevention, and better overall health.
 Warburg O. On the origin of cancer cells. Science 1956 Feb;123:309-14.
 Volk T, et al. pH in human tumor xenografts: effect of intravenous administration of glucose. Br J Cancer 1993 Sep;68(3):492-500.
 Kaaks R, Energy balance and cancer: the role of insulin and insulin-like growth factor-1. Proc Nutr Soc 2001 Feb;60(1):91-106
 Digirolamo M. Diet and cancer: markers, prevention and treatment. New York: Plenum Press; 1994. p 203.
 Brand-Miller J, et al. The glucose revolution. Newport (RI) Marlowe and Co.; 1999.
 Mooradian AD, et al. Glucotoxicity: potential mechanisms. Clin Geriatr Med 1999 May;15(2):255.
 Hoehn, SK, et al. Complex versus simple carbohydrates and mammary tumors in mice. Nutr Cancer 1979;1(3):27.
 Sanchez A, et al. Role of sugars in human neutrophilic phagocytosis. Am J Clin Nutr 1973 Nov;26(11):1180-4.
 Moerman CJ, et al. Dietary sugar intake in the aetiology of biliary tract cancer. Int J Epidemiol 1993 Apr;22(2):207-14.
 Seeley S. Diet and breast cancer: the possible connection with sugar consumption. Med Hypotheses 1983 Jul;11(3):319-27.
 Board M, et al. High Km glucose-phosphorylating (glucokinase) activities in a range of tumor cell lines and inhibition of rates of tumor growth
by the specific enzyme inhibitor mannoheptulose. Cancer Res 1995 Aug 1;55(15):3278-85.
 Chlebowski RT, et al. Hydrazine sulfate in cancer patients with weight loss. A placebo-controlled clinical experience. Cancer 1987 Feb 1;59(3):406-10.
 American College of Physicians. Parenteral nutrition in patients receiving cancer chemotherapy. Ann Intern Med 1989 May;110(9):734.
 Gatenby RA. Potential role of FDG-PET imaging in understanding tumor-host interaction. J Nucl Med 1995 May;36(5):893-9.