Heart-Friendly Fat

The fat-free-food craze is not all it's cracked up to be. Not only are Americans getting fatter in general, but studies show some of the fats being eliminated are good for heart health. In fact, Frank Hu, Ph.D., and colleagues at Harvard School of Public Health in Cambridge, Mass., found that increasing dietary intake of alpha-linolenic acid (ALA), an omega-3 essential fatty acid present in flax and canola oils, protects women against heart disease.

Using the subjects' food-frequency questionnaire from 1984, Hu examined the dietary habits of 76,283 U.S. women in the 1980-90 Harvard-based Nurses' Health Study. The women's ALA ranged from 0.71 g/day to 1.36 g/day. About 70 percent of their ALA intake came from oil-based salad dressing and mayonnaise.

By 1994, 232 women (0.3 percent) had died of heart disease and 597 (0.7 percent) had non-fatal heart attacks. Higher ALA consumption correlated with a lower risk of heart attack death. Women eating the most ALA reduced their risk by 55 percent compared with those eating the least.

Because salad dressing was the most significant source of linolenic acid in this study, using non-fat dressings may increase, rather than decrease, cardiac risk.

—American Journal of Clinical Nutrition 1999;69:890-7