A new long-term study that adds to the research on diet and breast cancer survival finds that women with certain types of breast tumors who reduced their dietary fat for years after diagnosis — and also lost weight — had lower death rates over the next 15 years than survivors on a standard diet.
The study was presented today at the San Antonio Breast Cancer Symposium and is not yet published in a journal.
It was funded in part by AICR and joins a growing body of research investigating how diet affects women diagnosed with breast cancer. In October, an AICR report on breast cancer survivorship in partnership with WCRF found some indication that fat may play a role in survival. The Continuous Update Project report found there was limited but consistent research suggesting that eating lower amounts of total fat and in particular, saturated fat, before a diagnosis of breast cancer linked to improved survival.
Weight loss may also play a role, as the low-fat group lost a a modest but significant amount of weight in this study. The CUP report found indications that being a healthy weight may lengthen survival for women diagnosed with breast cancer. But the report’s findings were not strong enough to make a specific recommendation.
For both pre- and postmenopausal breast cancers, the many studies looking on whether dietary fat matters has resulted in no clear conclusions. Now comes a study from Italy suggesting that it does for certain types of breast tumors, including the most common type.
The study suggests that consuming high amounts of total fat, and saturated fats specifically, links to increased risk of breast tumors fueled by the hormones estrogen and progesterone. About three quarters of US breast tumors are estrogen-receptor positive (ER+). The majority of those also grow in response to progesterone.
The increased risk was most pronounced for high amounts of saturated fat, the type of fat from burgers, butter and primarily animal sources.
Whether the amount of fat we eat affects our weight has been a hot topic of debate for years. Now, an analysis of the research finds that fat matters, and just switching higher-fat foods for their lower-fat counterparts – without any other dietary change – can help dieters lose a modest but significant amount of weight.
For the analysis, researchers looked at the 43 studies that compared a group of people who ate a low-fat diet to those eating the usual amount of fat. Thirty-three of those studies were randomized controlled trials (RCTs), lasting from six months over eight years and including almost 75,000 people.