Research reported recently in the medical journal Cancer Research suggests that fructose a monosaccharide found in sugar and high fructose corn syrup could be a risk factor for breast cancer development and its metastasis to the lungs.

High intake of fructose can be a possible risk factor for obesity, according to research conducted by Princeton University scientists who found that animals eating fructose were more likely to gain weight than glucose.  Both fructose and glucose are found in sucrose.  

The current study shows that among mice that were genetically prone to developing breast cancer, 30% of those fed a starch-dominant diet developed "breast cancer", compared to almost 60% of those fed a diet with an amount of sugar similar to that found in a typical Western diet.  Starch is a polysaccharide which consists of glucose only.

Researchers at The University of Texas MD Anderson Cancer Center who conducted the research also found mice eating the sugar-rich diet were more likely than those eating the starch-rich diet to experience lung metastasis.

The researchers explained the increased risk of breast cancer among mice fed the sugar-rich diet was due in part to the increased expression of an enzyme called 12-lipoxygenase which promotes oxidation of fatty acids such as arachidonic acid whose oxidation product 12-hydroxy-5Z,8Z,10E,14Z-eicosatetraenoic acid (12-HETE) was found high in breast tumors.

Sugar contains both fructose and glucose, but the study shows that fructose but not glucose was responsible to the increased lung metastasis of breast cancer and the increased formation of 12-HETE in breast cancer tumors.

The researchers concluded that "dietary sugar induces 12-LOX signaling to increase risks of breast cancer development and metastasis." (David Liu)

Yan Jiang, Yong Pan, Patrea R. Rhea, Lin Tan, Mihai Gagea, Lorenzo Cohen, Susan M. Fischer, and Peiying Yang, A Sucrose-Enriched Diet Promotes Tumorigenesis in Mammary Gland in Part through the 12-Lipoxygenase Pathway, Cancer Res; 76(1); 24–29.

Photo credit:  WiKIPEDIA