Women diagnosed with breast cancer during the Women's Health Initiative Dietary Modification trial who were following a lower-fat diet had increased breast cancer overall survival, although the increase was likely partly due to better survival from several causes of death

This study helps address the issue of postdiagnosis dietary intervention influences by providing findings for breast cancer overall survival measured from breast cancer diagnosis because study participants with breast cancer continued to participate in dietary modification activities.

The full study is published in JAMA Oncology.

The trial recruited 48,835 postmenopausal women with no previous breast cancer and dietary fat intake of more than 32 percent based on a food questionnaire.

19,541 participants took part in a dietary intervention to reduce their fat intake to 20 percent of calories and increase the amount of fruits, vegetables and grains they were eating, while 29,294 participants served as a usual-diet comparison group.

1,764 women were diagnosed with breast cancer during the dietary intervention.

Breast cancer overall survival was higher for women in the lower-fat group than in the usual-diet group, and in the group where women ate less fat, there were fewer deaths from breast cancer, other cancers and cardiovascular disease.

Source: JAMA Oncology