In a case-control study of 1,866 women in Mexico, those who derived 57 or more percent of their total energy intake from carbohydrates incurred a risk of breast cancer 2.2 times higher than women with more balanced diets. Dietary patterns in Mexico are characterized by higher consumption of carbohydrates and lower intake of fat and animal protein than those in more affluent western countries.
The team of researchers from the Instituto de Salud Pblica in Cuernavaca, Mexico, and the Harvard School of Public Health in Boston, suggests that the association between carbohydrates and breast cancer may be related to elevated levels of insulin and insulin-like growth factor binding proteins in the blood.
"Scientists have long suspected that diet was among the factors contributing to breast cancer," said study co-author Walter Willett, M.D., M.P.H., Dr.P.H, the Fredrick John Stare Professor of Epidemiology and Nutrition at the Harvard School of Public Health. "Now, with studies like ours, we are beginning gradually to understand what elements of diet specifically are associated with the disease, and to grasp the chemical and biological processes that contribute to it at the cellular level."
Of all the carbohydrate compounds, sucrose and fructose demonstrated the strongest association with breast cancer risk in the study. Sucrose is derived from sugar cane, sorghum and the sugar beet; it is most commonly found in table sugar and sweetened prepared foods and beverages. Fructose is a component of sucrose and is also found in fruit.
Eating sweets and starches causes a rapid rise in the body's blood sugar levels, which in turn cues the production of insulin and triggers a biological process that ultimately ca
Contact: Elizabeth J. Tait
American Association for Cancer Research