Researchers from University of Texas MD Anderson Cancer Centre have shown how a high intake of sugar can increase the risk of breast cancer and metastasis to the lungs.
This, scientists believe, is because of sugar's impact on inflammatory pathways in the body.
In the wake of the results, they hope to look further into the effects of sugar on tumour growth in mice.
Researchers conducted four different studies in which mice were fed one of four diets.
The study found that 30% of mice on starch diets had measurable tumours after six months. Meanwhile 50-58% of mice on a sucrose-enriched diet had mammary tumours by that same age.
It also found that numbers of lung tumours were significantly higher in mice on sucrose and fructose-enriched diets, compared to mice on a starch-control diet.
Peiying Yang, assistant professor of Palliative, Rehabilitation, and Integrative Medicine at the University Of Texas, said: "We found that sucrose intake in mice, comparable to levels of Western diets, led to increased tumour growth and metastasis, when compared to a non-sugar starch diet.
"This was due, in part, to increased expression of 12-LOX and a related fatty acid called 12-HETE."
Previous epidemiological studies have shown that dietary sugar intake has an impact on breast cancer development, with inflammation thought to play a role.
Lorenzo Cohen, professor of Palliative, Rehabilitation, and Integrative Medicine, added: "We determine 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 tumours."
Cohen said the data suggested that dietary sugar induces 12-LOX signalling to increase risks for breast cancer development and metastasis.
This is the first study to look at the direct link between sugar and cancer in animals. It was published in the online issue of Cancer Research.
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