A new prospective study has reported that a diet high in fruits and vegetables is associated with a lower risk of estrogen receptor negative (ER-) breast cancer in postmenopausal women. The study was designed to examine the associations between the Dietary Approaches to Stop Hypertension (DASH) diet overall, and animal-based and vegetable-based low-carbohydrate-diets in particular, on the risk of postmenopausal breast cancer. The study included 86,621 women in the Nursesí Health Study. The womens' diets were scored using data from up to seven food frequency questionnaires that they had filled out over time. The women were followed from 1980 through 2006, during which time a total of 5,522 cases of breast cancer were diagnosed, including 3,314 estrogen receptor positive (ER+) and 826 ER- cancers.

The DASH diet (high in plant foods while low in red meat, sodium and processed carbohydrates) was found to be associated with a 20% lower risk of ER- breast cancer when comparing the highest fifth to the lowest fifth of DASH scores and adjusting for other breast cancer risk factors. This risk reduction was largely explained by higher intakes of fruits and vegetables. Focusing on food groups rather than the DASH diet in particular, the authors also found a 19% lower risk of ER- breast cancer for a vegetable-based, low-carbohydrate-diet (i.e., high in vegetable protein from foods like beans and nuts, but low in refined carbs), as well as a 29% lower risk for a diet high in total fruit and low-protein vegetable intake. In other words, a diet high in plant protein and fat and moderate in carbohydrate content was associated with a lower risk of ER- cancer. On the other hand, no association was found between ER+ tumors and fruit and vegetable consumption.

Comments regarding the study

We suggest increasing consumption of specific fruits, vegetables and other foods that have been found to be associated with lower risk of breast cancer. For example, components of blueberries, broccoli and turmeric have each been found to reduce ER- breast cancer cell growth and proliferation. At the same time, foods that promote breast cancer should be limited or avoided. Please see our article on how to optimize your breast cancer diet for information on what to eat during all stages of treatment and recovery.