High glycemic load is a risk factor for some breast cancers

An extensive study just published in The American Journal of Clinical Nutrition adds more evidence to the link between a high glycemic load and certain types of breast cancer. The authors state:

"The glycemic potential of a diet is associated with chronically elevated insulin concentrations, which may augment breast cancer (BC) risk by stimulating insulin receptor or by affecting insulin-like growth factor I (IGF-I)–mediated mitogenesis."

They set out to determine if there is an association according to breast cancer phenotype using data from the European Prospective Investigation into Cancer and Nutrition(EPIC) on glycemic index (GI), glycemic load (GL), total carbohydrate intake correlated with incidence and type of breast cancer. Hormone receptor status turned out to be significant:

"Among postmenopausal women, GL and carbohydate intake were significantly associated with an increased risk of estrogen receptor–negative (ER−) BC when extreme quintiles (Q) were compared. Further stratification by progesterone receptor (PR) status showed slightly stronger associations with ER−/PR− BC. No significant association with ER-positive BC was observed."

In other words, the highest glycemic loads and carbohydrate intakes were associated with an increased risk estrogen receptor-negative breast cancer. The link was fortified for both estrogen and progesterone receptor-negative breast cancer. The authors state in conclusion:

"Our results indicate that a diet with a high GL and carbohydrate intake is positively associated with an increased risk of developing ER− and ER−/PR− BC among postmenopausal women."