Women who cut carbs in an effort to lose weight may be cutting their chances of developing breast cancer as well. New research from the Instituto Nacional de Salud Pública in Mexico in coalition with Boston’s Harvard School of Public Health found that women who followed a high-carbohydrate diet had a 2.2 percent greater risk of incurring breast cancer than those who adopted a more balanced diet (Cancer Epidemiology, Biomarkers, and Prevention, 2004, vol. 13, no. 8). The study was conducted in Mexico, where diets are characterized by higher carbohydrate and lower fat and animal-protein intake than that of other Western countries. Researchers examined the dietary habits of 1,866 pre- and postmenopausal women and determined that women who obtained 57 percent or more of their caloric intake from carbohydrates doubled their risk of developing the disease, even when other variables, such as socioeconomic status and family history of breast cancer, were taken into account.

Sucrose, or table sugar, and fructose, the sugar found in fruit, had the strongest associations with carbohydrate intake and cancer risk. Researchers speculate that the insulin released after eating such sugars could induce carcinogenesis by increasing cell proliferation and producing higher levels of active estrogen in the blood.

Given the amount of current attention on low-carbohydrate diets, health organizations in the United States caution that such findings shouldn’t be misread as a go-ahead for a high-protein, high-fat diet. According to the American Heart Association, high-fat foods, particularly those that contain unhealthy fats, augment your risk for several types of cancer.

Eliminating carbohydrates from your diet, especially those rich in fiber and made from whole grains, is certainly not recommended by researchers. The study of Mexican women showed that insoluble fiber, which is found in whole grains and vegetables, reduces the risk of developing cancer by slowing the rate of carbohydrate absorption. In addition, other studies have linked many of the United States’ fortified carbohydrate sources, such as enriched grains and cereals, to overall cancer prevention.