The high amounts of dietary sugar in the typical Western diet may increase the risk of breast cancer and metastasis to the lungs, according to a new study.

The findings, published in the journal Cancer Research, demonstrated dietary sugar's effect on an enzymatic signaling pathway known as 12-LOX (12-lipoxygenase).

 "We determined that it was specifically fructose, in table sugar and high-fructose corn syrup, ubiquitous within our food system, which was responsible for facilitating lung metastasis and 12-HETE production in breast tumors” said the author.

No previous studies have investigated the direct effect of sugar consumption on the development of breast cancer using breast cancer animal models or examined specific mechanisms.

The team conducted four different studies in which mice were randomized to different diet groups and fed one of four diets. At six months of age, 30 percent of mice on a starch-control diet had measurable tumors, whereas 50 to 58 percent of the mice on sucrose-enriched diets had developed mammary tumors. The study also showed that numbers of lung metastases were significantly higher in mice on a sucrose- or a fructose-enriched diet, versus mice on a starch-control diet.

The researchers state that moderate sugar consumption is critical, given that the per capita consumption of sugar in the U.S. has surged to over 100 lbs. per year and an increase in consumption of sugar-sweetened beverages has been identified as a significant contributor to an epidemic of obesity, heart disease and cancer worldwide.

Previous epidemiological studies have shown that dietary sugar intake has an impact on breast cancer development, with inflammation thought to play a role.

http://www.mdanderson.org/newsroom/news-releases/2015/sugar-diets-increases-risk-breast-cancer-tumors-metastasis.html