Feb. 22, 2008 (New Orleans) -- Fish oilsupplements don't pack the same stroke-preventive punch as a diet rich in fish, a new study suggests.
Eating foods rich in omega-3 fatty acids, such as fatty fish and some plant and nut oils, such as olive and walnut, has been shown to lower the risk of heart disease and stroke. Several public health organizations have recommended that people eat more oily fish, such as salmon and tuna.
But the role of omega-3 supplements in fighting cardiovascular disease has been less clear. Some studies show they have a protective effect and others show the opposite, says Craig Anderson, MD, director of the neurological and mental health division at the George Institute for International Health at the University of Sydney in Australia.
Anderson reasoned that if the supplements were really working to prevent stroke, they would modify the underlying disease process by lowering cholesterol and preventing blood clotting and other factors that contribute to stroke.
"What did we show? Nothing," Anderson tells WebMD. "The supplements didn't work."
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Fish Oil Fails
The study, presented at the American Stroke Association's International Stroke Conference, involved 102 men and women who had suffered an ischemic stroke.
The most common type of stroke, an ischemic stroke occurs when blood flow to an area of the brain is compromised by a blood clot. This leads to the death of brain cells and brain damage.
"We focused on ischemic stroke patients because they're highly motivated to follow preventive measures, they're at high risk of recurrent stroke, and they haven't been studied before," Anderson says.
The participants were randomly assigned to take either a daily fish oil supplement or a placebo for 12 weeks.
The supplements used in the study contained "more concentrated, fresher omega oils than can be bought in most health food stores," Anderson says.
Results shows that the supplements had no effect on any of the parameters measured, including total cholesterol, LDL "bad" cholesterol, HDL "good" cholesterol, and other lipid levels. There was no change in markers of the tendency of blood to clot and no evidence of an anti-inflammatory effect. Inflammation of the blood vessels may play a role on causing stroke.