Women with breast cancer who eat a diet that is lower in fat may survive longer, a new study finds.

For nearly a half-century, research has suggested a link between dietary fat intake and breast cancer survival but the results of these studies, which have been observational, have been mixed.

In this study, researchers from the Los Angeles Biomedical Research Institute found that women with invasive breast cancer who followed a low-fat diet for at least eight years improved their probability of survival.

They conducted additional analysis of a dietary trial that was part of the Nurse’s Health Study. The study involved 48,835 postmenopausal women who had been followed for eight years.

The women were age 50-79, had no prior breast cancer, normal mammograms and normal dietary fat intake. Of those, 19,541 women were put on a low-fat diet with nutritionist-led group sessions that sought to reduce fat intake reduction to 20 percent of energy and increase the consumption of fruits, vegetables and grain. The other 29,294 women in the trial followed their usual dietary patterns.

After approximately eight years of remaining on the low-fat diet, 1,767 of the women were diagnosed with breast cancer. Researchers found the breast cancer overall survival from diagnosis was higher in the dietary group: 82 percent versus 78 percent. The researchers said this reduction is due, in part, to better survival following breast cancer diagnosis.

"This was the first time we had examined the deaths after breast cancer among this group, and we found that a sustained low fat diet increased the survival rates among postmenopausal women after a breast cancer diagnosis," said Dr. Rowan Chlebowski, the lead author of the study, who presented it at the American Association for Cancer Research’s annual meeting.