All Fats Are Not Created Equal: Some Fats May Protect The Heart

Reporting in today's issue of Circulation: Journal of the American Heart Association Penny M. Kris-Etherton, Ph.D., R.D., the author of the statement and a member of the American Heart Association Nutrition Committee, says, "Previous studies have associated a Mediterranean-style diet with a lower risk of heart disease. These diets are rich in monounsaturated fats, primarily olive oil," says Kris-Etherton.

Other good sources of monounsaturated fats are peanuts and other nuts, avocados, and olives. Nuts, seeds and fish are good additional sources of polyunsaturated fats.

"These studies are telling us that the type of fat may be as important as how much of it is eaten," she says.

Many Americans have been trying to cut the fat from their diets by eating more grains, fruits, vegetables and other carbohydrates. Such a diet tends to lower LDL cholesterol, the so-called 'bad' cholesterol. However, high carbohydrate diets may also reduce the 'good' cholesterol, HDL, and raise triglycerides. Blood vessels narrowed by a buildup of LDL cholesterol are more likely to be blocked by blood clots, causing a heart attack or stroke.

Kris-Etherton says a diet containing monounsaturated or polyunsaturated fats will not reduce a person's HDL cholesterol.

"Some studies have found that these monounsaturated and polyunsaturated fats may make the platelets -- clotting components in the blood -- less sticky and less likely to form clots," she says. Blood clots in the blood vessels can trigger a heart attack or stroke.

"Monounsaturated fatty acids may help to dissolve clots if they do form," says Kris-Etherton, a distinguished professor of nutrition at Penn State University.

Another plus is that a diet higher in monounsaturated or polyunsaturated fats can help improve control of blood cholesterol in people with Type II diabetes better than a very high-carbohydrate diet. However, individuals with Type II diabetes need to continue to keep their weight under control. Substituting unsaturated fats for carbohydrates avoids the reduction in HDL cholesterol and the rise in triglyeride levels associated with high carbohydrate diets.

Kris-Etherton emphasizes the importance of controlling total calorie intake to avoid weight gain in individuals with diabetes, a disease that occurs when the body makes insulin but cannot use it efficiently. The number of people affected by the disease is expected to rise as the population ages.

"This is especially important, because of the growing number of individuals who are overweight and obese," she says.

The American Heart Association's current dietary guidelines recommend limiting total fat consumption to no more than 30 percent of daily calories. Saturated fat should comprise no more than 8 to 10 percent of total calories, and total unsaturated fat should be limited to no more than 20 to 22 percent of total daily calories.

"Working within these ranges of fat intake allows considerable flexibility in diet planning," says Kris-Etherton.