February 24, 2016. Findings from a clinical trial reported on December 29, 2015 in the journal Cancer Prevention Research indicate an association between supplementation with omega-3 polyunsaturated fatty acids by obese women and a reduction in breast density which, when increased, is a biomarker for the development of breast cancer. "The higher the breast density, the more likely the woman will develop breast cancer," explained lead researcher Andrea Manni of Hershey Medical Center in Hershey, Pennsylvania.
Dr Manni and colleagues randomized 266 postmenopausal normal weight, overweight and obese women to receive a 30 milligram (mg) dose of the antiestrogen drug raloxifene, 60 mg raloxifene, fish oil sourced omega-3 fatty acids EPA and DHA, 30 mg raloxifene plus omega-3, or no treatment daily for two years. Breast density and plasma omega-3 fatty acid levels were assessed at the beginning and end of the trial.
At the trial's conclusion, obese participants with elevated levels of DHA experienced a reduction in breast density, which Dr Manni suggests was due to a decrease in inflammation. The finding could help explain the varying results of studies that evaluated omega-3's protective effect against breast cancer, since women of normal weight have less inflammation and would therefore experience less benefit. "Omega-3 fatty acids have an anti-inflammatory effect, so that's one of the reasons why we suspected it may be particularly effective in obese women," stated Dr Manni, who is a professor and division chief of endocrinology, diabetes and metabolism at Penn State College of Medicine.
"The finding supports the idea that omega-3s, and specifically DHA, are preferentially protective in obese postmenopausal women," Dr Manni concluded. "This represents an example of a personalized approach to breast cancer prevention."
The researchers plan to evaluate the effect of DHA alone a future trial of obese women.