A new study shows that a little tweaking of diets already known to be good for the heart appears to make them even better, says The Early Show medical correspondent Dr. Emily Senay.
Health experts agree that limiting saturated fats such as those in red meat and butter lowers a person's risk of heart disease, Senay points out. And a widely-studied heart-healthy alternative, known as the "DASH" diet, which stands for Dietary Approaches to Stop Hypertension, is recommended for controlling high blood pressure.
The "DASH" diet falls within current United States dietary guidelines. It's low in saturated fat, cholesterol, sodium and sweets, and high in carbohydrates like those found in fruits, vegetables, and fiber. It's also high in potassium and other minerals. In addition, the eating plan includes smaller amounts of lean meats, poultry, fish, legumes, and nuts.
New research in the Journal of the American Medical Association compared a diet similar to the "DASH" diet with two other healthy diets that differed in proportions of protein, fats and carbohydrates.
The study found that replacing carbs with protein or "good" unsaturated fats can further decrease the risk of heart disease, Senay says.
Three different diets were prescribed to patients with elevated or high blood pressure. Researchers watched their blood pressure, cholesterol and triglycerides to determine their risk of heart disease.
The healthy high-carb diet reduced the risk of heart disease by sixteen percent. A second diet that replaced ten percent of the carbs with "good" unsaturated fat like that found in olive oil, vegetable oils, nuts and seeds reduced the risk of heart disease by almost twenty percent. A third diet that replaced ten percent of carbs with protein — mostly beans, nuts, seeds and certain grains — decreased heart disease by twenty-one percent. Other replacement protein included poultry, egg substitutes, and fat-free or low-fat milk products.
The study suggests that just slightly tweaking the components of a healthy diet can make a big difference in reducing heart disease risk factors, Senay observes.
All the diets lowered blood pressure. But there were differences in the way they affected cholesterol and triglycerides.
The protein-rich diet lowered both LDL, or "bad" and HDL, or "good" cholesterol, and lowered triglycerides. The "good" fat diet lowered triglycerides, raised HDL, or "good" cholesterol, but didn't have a significant effect on LDL, or "bad" cholesterol, Senay says.
The study didn't look at diets extremely high in saturated fat and low in carbs, such as the Atkins Diet, or any of the other popular low-carb diets.
The new information doesn't yet mean that current dietary guidelines will be changed, Senay adds. The proportions of carbohydrate, protein, and fat for all three diets are within the ranges recommended in current dietary guidelines.