The truth isn’t so sweet: UT researchers at the M.D. Anderson Cancer Center recently found that consuming sugar increases risk of cancerous growths in the lungs and breast cancer.

The average American consumes 22 teaspoons of added sugar per day, three times more than the American Heart Association’s daily recommendation. The researchers found that table sugar and high fructose corn syrup were responsible for enabling malignant, or cancerous, growth in mice. They published their work in January 2016 with the American Association for Cancer Research. 

Peiying Yang, M.D. Anderson head researcher, said the magnitude of the obesity problem in the United States motivated the team to study a possible link between sugar consumption and cancer.

“Identifying risk factors for breast cancer is a public health priority,” Yang said. “However, the mechanisms by which the added sugars impact breast cancer development remain unclear. This prompted us to conduct the preclinical research to identify the role of sugar in breast cancer and its underlying molecular mechanism.”

The researchers gave four groups of mice different levels of sugar and found that mice fed a diet high in sugar, comparable to American diets, developed lung cancer growths and breast cancer tumors. According to the study, between 50 and 58 percent of the mice fed a sucrose-rich diet, or high in sugar, developed tumors compared to the 30 percent of mice that consumed a non-sugar starch diet.

Yang said the study revealed that sugar causes the production of 12-LOX and 12-HETE in breast tumor cells, which in turn causes tumors to grow. 12-LOX is a signaling pathway that, when chemically altered through enzymatic processes, produces an acid called 12-HETE. This process, according to Yang, plays a key role in inflammatory diseases like obesity and cancer. 

“12-HETE enhances the invasion and potential for prostate cancer, as reported by our own laboratory and other investigators,” Yang said. “A recent preclinical study further documented that 12-HETE serves as a key mediator of tumor cells.”

Studies in 2014 by the National Center for Biotechnology Information and in the 2015 New England Journal of Medicine concluded that a diet high in sugar will lead to obesity and other factors that increase the risk for cancer, but the M.D. Anderson study found a direct link.

Yang said M.D. Anderson will soon begin studying the impacts of sugar on patients who have already developed breast cancer. 

“The optimal goal of our project is to examine the impact of sugar in patients with breast cancer by modifying their dietary sugar intake,” she said. “In the very near future, we would be interested in learning the impact of other sweeteners in breast cancer development and progression.”