For some time the medical community has warned us about the well-established link between diet and the risk of developing cancer. Every day, it seems, new studies contribute yet another piece to this complex puzzle.

Now there's evidence that fructose, a type of sugar, is associated with pancreatic cancers.

Sugar

There are several kinds of sugar. To make sense of how they influence cancer risk and development, it helps to understand the difference.

  • Ordinary table sugar (sucrose),
  • cane and beet sugar,
  • honey,
  • molasses,
  • and other syrups are all natural forms of sugar.

Glucose, which is present in our cells, and fructose are also natural sugars. Many fruits, honey, and some root vegetables contain fructose, the sweetest sugar. Fructose is one of the main ingredients in the much-maligned High-Fructose Corn Syrup (HFCS). Food manufacturers produce HFCS by converting some of the glucose in corn to fructose. They use it extensively to preserve and sweeten processed foods. We also produce fructose when we digest food.

Sugar and Cancer

Until now, scientists knew that glucose played a role in cancer development. In healthy cells, the presence of oxygen prevents glucose from breaking down (glycolysis), which is a good thing. However, cancer cells cause glycolysis even when there is oxygen in the cells, fueling cancer cell growth. In other words, high levels of glucose in the body increases the risk of cancer by creating a metabolic environment conducive to tumor growth.

Elevated blood glucose is associated with both an increased risk of the incidence of cancer as well as cancer fatalities. In men, for example, high glucose is linked to an increased risk of developing liver, gallbladder, respiratory tract, thyroid, and myeloma, and an increased risk for fatal colon cancer.

In women, the link between glucose and cancer-especially fatal cancers-is even stronger. Researchers found these results held even when they controlled for Body Mass Index (associated with obesity) and smoking, which are both are also significant risks for cancer.

Recently, scientists learned that fructose also promotes cancer cell growth in pancreatic cancer, albeit in a slightly different manner. Fructose activates key pathways that drive cell division, which helps cancer cells proliferate and grow faster than normal, healthy cells. It's likely this process occurs in other types of cancer as well.

Although you can't eliminate all sugar from your diet because so much of it occurs naturally in food, you can reduce excess sugar simply by eliminating sugary drinks, such as soda, and eating less processed foods.

 

Sources:

"Fructose Encourages Pancreatic Cancer Growth." Medical News Today. Web. 3 August 2010. http://www.medicalnewstoday.com/articles/196572.php

Liu, Haibo, Huang, Danshan, McArthur, David L. Boros, Laszlo G., Nissen, Nicholas, and Heaney, Anthony P.  "Fructose Induces Transketolase Flux to Promote Pancreatic Cancer Growth." Cancer Research 70: 6368-6376. Web. 20 July 2010.http://cancerres.aacrjournals.org/content/70/15/6368.abstract

Young, Christian D., and Anderson, Steven M. "Sugar and Fat - That's Where it's at: Metabolic Changes in Tumors."  Breast Cancer Research 10(1) (2008). Medscape Medical News. Web. 19 August 2008. http://www.medscape.com/viewarticle/577935

Hung, Mindy. "High Dietary Glycemic Load May Increase Colorectal Cancer Risk in Women." Journal of the National Cancer Institute 96 (2004): 229-233. Medscape Medical News. Web. 3 February 2004. http://www.medscape.com/viewarticle/468225

Collins, Karen MS, RD, CDN. "Sugar, Corn Syrup or Calories?" Nutrition Notes. American Institute for Cancer Research. Web. 8 September 2008.www.aicr.org/site/News2?page=NewsArticle&id=13829 - 27k

Stocks, Tanja, Rapp, Kilian, Bjørge, Tone, Manjer, Jonas, Ulmer, Hanno, Selmer, Randi, Annekatrin, Lukanova, Johansen, Dorthe, Concin, Hans, Tretli, Steinar, Hallmans, Görans, HåJonsson, and Stattin, Par. "Blood Glucose and Risk of Incident and Fatal Cancer in the Metabolic Syndrome and Cancer Project (Me-Can): Analysis of Six Prospective Cohorts." Public Library of Science Medicine 6(12) (2009). Web. 19 January 2010. http://www.medscape.com/viewarticle/714861