NEW YORK (Reuters Health) - Fish oil supplements appear to lower the risk of heart disease in postmenopausal women regardless of whether they are taking hormone replacement therapy (HRT), researchers suggest.

Their findings, published in the August issue of the American Journal of Clinical Nutrition, show that the supplements reduce levels of specific fatty acids in the blood that are associated with heart disease. Taking fish oil supplements containing omega-3 fatty acids could reduce the risk of heart disease in postmenopausal women by 27%, the report indicates.

``These results show that supplementation with a fish oil-derived concentrate can favorably influence selected cardiovascular disease risk factors...in postmenopausal women receiving and not receiving HRT,'' according to Ken D. Stark and colleagues with the University of Guelph in Canada.

They explain that compounds in fish oil supplements are thought to inhibit the production of certain fatty acids in the liver and reduce the rate at which other fatty acids are secreted into the bloodstream.

Previous studies have shown that fish oil supplements may reduce the risk of developing heart disease for men. However, their effect on women has not been well studied. The present findings are particularly important for postmenopausal women, since heart disease is the leading cause of death in this group.

During menopause, the body produces less estrogen, a hormone that has a protective effect on the heart. HRT, which includes estrogen, may lower the risk of heart disease but it is also associated with an increased risk of certain cancers. For this reason, some women choose not to take hormones.

To investigate the effect of fish oil on cardiovascular risk factors, researchers gave a group of postmenopausal women, aged 43 to 60, either eight fish oil capsules a day or a placebo (inactive) oil capsule. After 4 weeks, the investigators measured the composition of fat in the blood.

The researchers call for further studies investigating the interaction of omega-3 fatty acids with specific HRT regimens.

SOURCE: American Journal of Clinical Nutrition 2000;72:389-394.