Previous studies have suggested that fish oil supplements may reduce the risk of an additional heart attack or stroke in patients who have recently experienced a heart attack. Now new study findings reveal that the supplement also reduces the risk of sudden death.

The findings show that this reduced risk was evident after as few as 3 months, which seems to support the hypothesis that adding n-3 polyunsaturated fatty acids — commonly found in fish and fish oil — to a healthy diet may lower the risk of fatal arrhythmia, an irregular heartbeat that in severe cases can lead to cardiac arrest.

Reduction of sudden death appeared early after start of treatment. This seems to support the idea that omega-3 fats could be due to an anti-arryhythmia effect.

The study included 11,323 patients who had suffered a heart attack within the previous 3 months. All of the patients received the same preventive care and ate Mediterranean-style diets rich in fruits, vegetables, olive oil and fish. But some patients also consumed 1 gram of the fish oil supplements per day.

During the 3.5-year follow-up period, 1,031 individuals died.

Patients who took the fish oil supplements appeared to be at a 41% lower risk of death from any cause after only 3 months of treatment, study findings indicate.

After 4 months of treatment, these patients also appeared to be at a significantly reduced risk of sudden cardiac death. And by the end of the study period, patients treated with fish oil supplements were 45% less likely to die suddenly from a heart-related cause.

One capsule of a fish oil concentrate daily for 3.5 years resulted in a very significant reduction in sudden cardiac death. Thus, a simple and safe change in diet can potentially produce a large public health benefit.

Circulation April 2002;105