What is ER-negative breast cancer? It occurs when someone develops a tumor that lacks receptors for the hormone estrogen. These estrogen receptor-negative (ER-negative) tumors account for about one-quarter of all breast cancers.
The research team analyzed data from a large, long-running study of U.S. nurses. Eighty-six thousand women were followed for 26 years. The researchers looked for those who developed ER-negative breast cancer.
The researchers found that ER-negative breast cancer was lower among women whose diets most closely resembled the Dietary Approaches to Stop Hypertension (DASH) diet — an eating plan experts recommended for lowering blood pressure. The diet emphasizes vegetables, fruit, fiber-rich grains, legumes and nuts, and low-fat dairy.
Women who had the highest DASH score at the outset were 20% less likely to develop ER-negative breast cancer than those with the lowest DASH scores. The researchers noted, on closer examination, that it was likely the high vegetable and fruit intake that mainly accounted for the link.
Recent research has suggested that the risk of ER-negative breast tumors, in particular, may be related to diet — but exactly why remains somewhat of a mystery. The researchers speculate that ER-positive breast tumors grow when supplied with estrogen, but that certain foods help to block this supply.
The best advice for women is that a healthy approach to eating will also most likely be associated with a lower risk of certain breast cancers. And vegetables may be especially important.
Along with the DASH findings, the study also showed that women with diets high in vegetable protein — from foods like beans, soy and nuts — but low in refined carbs (like white bread and other starchy foods) had a 19% lower risk of ER-negative cancer, versus women with the opposite diet pattern.
To sum up: try to get four to five servings of vegetables and the same amount of fruit each day. Another recommendation would be to get four to five servings of legumes, nuts and seeds per week.