To Reduce Risk of Breast Cancer, Opt for a Plant-Rich Diet: Study
Women now have another reason to fill their plates with fruit and vegetables.
Plant-rich diets may help them ward off breast cancer, a new study suggests.
The findings, which are taken from a long-running study of nurses, show that women with diets high in fruit, vegetables and legumes — but low in red meat, sodium and processed carbohydrates — tend to have a lower risk of developing certain breast tumors.
Specifically, they were less likely to develop breast tumors that lack receptors for the hormone estrogen. These estrogen receptor-negative tumors account for about a quarter of all breast cancers.
The study followed more than 86,000 women for 26 years, and slightly less than 1 percent of them developed ER-negative cancer.
The risk, researchers found, was lower among those women whose diets most closely resembled a plan that helped reduce blood pressure.
Called the Dietary Approaches to Stop Hypertension diet, the eating plan recommends that the average woman should get four to five servings of vegetables and the same amount of fruit each day. It also recommends four to five servings of legumes, nuts and seeds each week.
Women who achieved the highest DASH scores from the outset of the study were 20 percent less likely to develop ER-negative breast cancer than those with the lowest DASH scores.
When the researchers took a closer look at the data, they noticed that a higher intake of fruits and vegetables seemed to account for the link.
The results, reported in the American Journal of Epidemiology, do not prove that a plant-rich diet itself cuts breast cancer risk.
And in general, studies have come to mixed conclusions on whether diet habits are connected to breast cancer.
However, recent research has been suggesting the risk of ER-negative breast tumors, in particular, may be related to diet, explained Teresa T. Fung, an associate professor of nutrition at Simmons College in Boston and the lead researcher on the new study.
Fung speculated that with ER-positive breast tumors — whose growth is fueled by estrogen —the hormone’s influence may be so important that it “overwhelms” potential dietary benefits.
The bottom line
In the end, Fung said, it is important to remember that generally healthy eating habits may be associated with a lower risk of certain breast cancers, and vegetables may be especially key.
Along with the DASH findings, the study showed that women fared better with diets high in vegetable protein — found in beans, soy and nuts — so long as they reduced their intake of refined carbohydrates like white breads and starchy foods.
In fact, they had a 19 percent lower risk of ER-negative cancer than those with the opposite diet pattern.
Of course, as Fung pointed out, “healthy behaviors don’t occur in isolation.”
But when the researchers accounted for factors like weight, exercise habits and smoking, the link between plant-rich diets and lower breast cancer risk still held strong.
Again, that does not prove cause and effect, Fung acknowledged. And the researchers could only look at the risk across large groups of women. Therefore, the effect of plant-rich diets on any one woman is still unclear.
The average American woman has a 12 percent chance of developing breast cancer in her lifetime, and ER-positive cancers are the most common.
Fung suggested that women who have less-than-ideal diets could gradually introduce healthier fare to their plates. That way, the dietary changes can seem less daunting.
“Find one item you can work on,” Fung said. “Maybe start by adding beans. Any improvement is better than no improvement.”