Pancreatic cancers use fructose, a sugar very common in the Western diet, to grow more quickly and proliferate, researchers have found. The study challenges the general wisdom that all sugars are the same. Although it’s widely known that cancers use glucose, a simple sugar, to fuel their growth, this is the first time a link has been shown between fructose and cancer proliferation, says Anthony Heaney, an associate professor of medicine and neurosurgery, at UCLA’s Jonsson Cancer Center and senior author of the study that was recently published in the journal Cancer Research.

“The bottom line is the modern diet contains a lot of refined sugar including fructose and it’s a hidden danger implicated in a lot of modern diseases, such as obesity, diabetes and fatty liver,” says Heaney. “In this study, we show that cancers can use fructose just as readily as glucose to fuel their growth.”

Sources of fructose in the Western diet include cane sugar and high fructose corn syrup, a corn-based sweetener that has been on the market since about 1970. High fructose corn syrup accounts for more than 40 percent of the caloric sweeteners added to foods and beverages, and it is the sole sweetener used in American soft drinks.

The consumption of high fructose corn syrup in the United States increased more than 1,000 percent between 1970 and 1990, according to the American Journal of Clinical Nutrition. Food companies use it because it’s cheap, easy to transport and keeps foods moist.

In the study, Heaney and his team took pancreatic tumors from patients and cultured and grew the malignant cells in petri dishes. They then added glucose to one set of cells and fructose to another. Using mass spectrometry, they were able to follow the carbon-labeled sugars in the cells to determine what exactly they were being used for and how.

Heaney found that the pancreatic cancer cells could easily distinguish between glucose and fructose even though they are very similar structurally, and contrary to conventional wisdom, the cancer cells metabolized the sugars in very different ways. In the case of fructose, the pancreatic cancer cells used the sugar in the transketolase-driven non-oxidative pentose phosphate pathway to generate nucleic acids, the building blocks of RNA and DNA, which the cancer cells need to divide and proliferate.

“Traditionally, glucose and fructose have been considered as interchangeable monosaccharide substrates that are similarly metabolized, and little attention has been given to sugars other than glucose,” the study says. “However, fructose intake has increased dramatically in recent decades and cellular uptake of glucose and fructose uses distinct transporters ... these findings show that cancer cells can readily metabolize fructose to increase proliferation. They have major significance for cancer patients, given dietary refined fructose consumption.”

Heaney thinks the government should make an effort, such as it did with smoking, to reduce refined fructose intake. “I think this paper has a lot of public health implications,” he says. “Hopefully, at the federal level there will be some effort to step back on the amount of high fructose corn syrup in our diets.”

While the study was done in pancreatic cancer, the results may not be unique to that cancer type. Going forward, the researchers using cell lines and mice to explore whether it’s possible to block the uptake of fructose in the cancer cells with a small molecule, taking away one of the fuels they need to grow.