New results from the Women’s Health Initiative Dietary Modification trial presented at the 2019 ASCO’s (American Society of Clinical Oncology) Annual Meeting show that postmenopausal women directed to a low-fat diet were less likely to die of breast cancer.

The study randomly assigned 48,835 postmenopausal women – women who no longer get periods – to either continue their usual eating habits or follow a low-fat diet. The diet group attended regular group meetings and emphasized fruits, vegetables, and grains. The participants followed the diet or usual eating habits for 8.5 years, Eric Fitzsimmons reports from ASCO.

Earlier studies from this trial were not able to link a low-fat diet to a lower risk of dying from breast cancer. But women in the diet group who were diagnosed with breast cancer were 15 percent less likely to die of any cause than women in the control group who were diagnosed with breast cancer. Women in the low-fat diet group were also 21 percent less likely than those in the regular diet group to die from any cause.

In this latest report, after 19.6 years of follow up, there was a lower rate of deaths from breast cancer in the diet group than in those who ate their usual diet.

Because this study is observational, observing people over time, it can only show an association between a low-fat diet and a lower risk of dying from breast cancer. The original study followed healthy women over time, and some later developed breast cancer. So the role of the low-fat diet before diagnosis, and its effect on risk for recurrence or death, remains unclear. But moving to a healthier diet and lifestyle has been shown to lessen the impact of some side effects and increase overall health. If you have interest in making changes to your diet, talk with your doctors.