Sugar and Cancer


When so many people are eating their Valentine’s Day candy, many cancer patients, and those who hope to prevent cancer might end up avoiding not only the candy, but any food that they classify as “sugar.”  This stems from a common belief that “sugar feeds cancer.” This statement oversimplifies a complex situation and can lead to a lot of confusion and unnecessary stress for those concerned about a cancer diagnosis.

The first thing to know is that while many people think of sugar as the substance used to sweeten our coffee and baked goods, when it comes to the sugar that helps the body function the most common term is actually glucose.  Any form of sugar, and many other foods, are broken down into glucose that is carried in our blood and used to fuel all cells in the body.  So it is true that sugar feeds cancer cells, because it feeds all cells in our bodies.  Even if a person was to eliminate all added sugar from their diet, as well as naturally occurring sugars in fruits, vegetables, legumes and whole grains, their body would still find a way to create glucose, breaking down protein, fat and maybe even their own muscles.3 

Thousands of research studies have been and are being undertaken on the connection between glucose and cancer, yet there are no definitive answers.  Many studies suggest that there might be a link, but they will admit themselves that “further studies are needed to clarify whether glucose is a proxy of other lifestyle-related or metabolic factors.”6 There is no definitive study that proves causation between elevated blood glucose with cancer risk or aggressiveness.  So eliminating sugar from your diet isn’t likely to cure your cancer, in fact “solid tumours are dependent on glucose, but […] cancer cells can generally survive glucose deprivation better than their normal counterparts.”5

Many health professionals believe that the connection between glucose and weight gain actually sits at our waistlines.2 Most people who eat excess sugar carry excess fat and weight.  Being overweight has been linked to an increased risk of many cancers including breast, colorectal and pancreatic cancers.  Eating a lot of simple sugars, i.e. cakes, cookies, heavily processed foods, can cause a spike in insulin.  Insulin can encourage cell growth, which is good for healthy cells, “however, excess insulin may encourage cancer cells to grow more, which is not a good thing.”4 The American Institute for Cancer Research says that the best thing to do to lower cancer risk with nutrition is to “choose a diet high in vegetables, fruits, legumes, whole grains and low fat dairy with moderate amounts of animal protein; limit foods with a lot of added sugar.”1 Vadel Shivers a registered dietician and certified specialist in oncology nutrition with Mary Bird Perkins – Our Lady of the Lake Cancer Center, says “Fruits, vegetables, whole grain breads,  brown rice, and beans all contain some sugar but have been shown to be helpful in preventing cancer.  So, avoiding these foods just because they contain sugar does not make any sense. The primary focus of everyone should be to limit or avoid processed foods and simple sugars.”


1. American Institute of Cancer Research (n.d.). Cancer Myths Exposed. Retrieved from

2. Espat, A. (2012, November). Does Cancer Love Sugar. Retrieved from

3. Ludington, K. (n.d.). Sugar and Cancer Cells. Retrieved from

4. Mahtani, R. (2010, August). Sugar and Cancer: Is there a Connection. Retrieved from

5. Wu, H., Ding, Z., Hu D., Sun, F., Dai, C., Xie, J., & Hu, X.(2012).Central role of lactic acidosis in cancer cell resistance to glucose deprivation-induced cell death[Abstract]. Journal of Pathology. 2012 Jun; 227(2):189-99.doi: 10.1002/path.3978.

6. Wulaningsih, W., Holmberg, L., Garmo, H., Zethelius, B., Wigertz, A., Carroll, P., ... Van Hemelrijck, M. (2013).Serum Glucose and Fructosamine in Relation to Risk of Cancer[Abstract].PLoS One. 2013; 8(1): e54944. doi: 10.1371/journal.pone.0054944.

Disclaimer: Health information provided by the library and education center should not be used in place of advice from a qualified physician or healthcare provider. You are encouraged to ask your healthcare provider to interpret any health information found in the library or on online.