Fish oils link to lower breast cancer risk

Reduces cancer risk by a third, study finds

Many claims have been made for fish oil supplements containing omega-3, some less credible than others. But a new American study suggests regularly taking omega-3 supplements can reduce a woman's risk of breast cancer by up to a third.

In the study, more than 36,000 postmenopausal women without a a history of breast cancer completed questionnaires about their non-vitamin, non-mineral "specialty" supplements. The women were then tracked for up to six years later. 

During this time, 800 women developed breast cancer.

Results of the study

The researchers found that regular use of fish oil supplements, which contain high levels of the omega-3 fatty acids, EPA and DHA, was linked with a 32 per cent reduced risk of breast cancer. The reduced risk appeared to be restricted to invasive ductal breast cancer, the most common type of the disease.

No beneficial link was found for any other types of supplement take by the women.

This research is the first to demonstrate a link between the use of fish oil supplements and a reduction in breast cancer. Findings from past studies of dietary intake of fish or omega-3 fatty acids have not been consistent.

More work needed

Commenting on the result, study author Emily White suggested that "it may be that the amount of omega-3 fatty acids in fish oil supplements are higher than most people would typically get from their diet."

It should be noted that the study relied on women self-reporting their habits. This is an unreliable source of data at the best of times, therefore more work is needed before it can be said that taking Omega-3 supplements will definitely cause a reduction in breast cancer risk.

This point was echoed by the Harvard medical professor Edward Giovannucci: "It is very rare that a single study should be used to make a broad recommendation," he said. "Over a period of time, as the studies confirm each other, we can start to make recommendations."

Published in Cancer Epidemiology, Biomarkers & Prevention, the study was carried out at the Fred Hutchinson Cancer Research Center in Seattle, USA.

The Family GP