Does Dietary Fat Link to Breast Cancer Risk?
For both pre- and postmenopausal breast cancers, the many studies looking on whether dietary fat matters has resulted in no clear conclusions. A recent study from Italy now suggests that dietary fat does link to certain types of breast tumors, including the most common type. The study was published in the Journal of the National Cancer Institute.
In the study, consuming high amounts of total fat, and saturated fats specifically, linked to increased risk of breast tumors fueled by the hormones estrogen and progesterone. About three quarters of US breast tumors are estrogen-receptor positive (ER+). The majority of those also grow in response to progesterone. The increased risk was most pronounced for high amounts of saturated fat, the type of fat from burgers, butter and primarily animal sources.
In this study, the researchers used dietary questionnaires and other data from approximately 337,000 women. The women are part of EPIC, the European Prospective Investigation into Cancer and Nutrition. After almost 12 years, 10,062 of the women had developed breast cancer. Then the researchers separated the cancers into whether they were ER+, PR+ or HER2+, tumors that respond to a protein called human epidermal growth factor receptor 2. (Data was not available for all women.)
Compared to the women who were consuming the least saturated fats per day, the women who were eating the highest amounts had a 28 percent increased risk of ER+/PR+ tumors. For those same tumors, the risk was slightly lower but still significant for the highest category of total dietary fat intake compared to the lowest.
This is after adjusting for the women’s weight, age, calories from alcohol and other factors linked to risk.The mechanisms are unclear. And more research is needed.
Source: Sabina Sieri et al. "Dietary Fat Intake and Development of Specific Breast Cancer Subtypes." JNCI J Natl Cancer Inst.