Evidence continues to mount on the protective effect of polyunsaturated fatty acids (PUFAs) on the heart.

In a large Italian trial involving more than 11,000 patients surviving recent heart attacks, participants were randomly assigned supplements of n-3 polyunsaturated fatty acids (1 g daily), vitamin E (300 mg daily), a component of fish oils, both supplements or no supplements over a study period of three to five years.

During this time, the researchers monitored the number of deaths, non fatal heart attacks and strokes.

At the end of the study period, the researchers concluded that treatment with n-3 PUFA, but not vitamin E, significantly lowered the risk of each of these adverse incidents. The risk of death from any of the measured causes was reduced by between 14 to 20 per cent, and the risk of cardiovascular death was reduced by 17 to 30 per cent.

The group taking vitamin E on its own showed no improvement over controls; and the group taking n-3 PUFA and vitamin E were similar to those who took PUFA on its own. This lead the researchers to conclude that it was n-3 PUFA, and not vitamin E, which exerted the most beneficial effect.

The results for n-3 PUFA are not surprising, but they do challenge some long held beliefs about the protective effects of vitamin E on the heart. However, the authors acknowledge that the dosage of vitamin E in this trial was lower than those used in previous trials (Lancet, 1999; 354: 447-55).