Diet is an important part of a heart-healthy lifestyle. Numerous studies show that both a low-fat diet and a Mediterranean diet can help people with high cholesterol or obesity reduce their risk of coronary heart disease (CHD) that leads to heart attacks. But which diet works better?

Recent development: A new study from researchers at Maimonides Biomedical Research Institute of Cordoba, Spain, is the first study to show that diet can reduce the risk of a second heart attack in people who have already had a CHD event. They compared a Mediterranean diet with a low-fat diet and found that both diets helped, but the Mediterranean diet worked significantly better.

When someone has CHD, the inner lining of the arteries that supply heart muscle is damaged. This lining is called the endothelium. Repair of the endothelium and endothelial function are the keys to recovery and prevention of another heart attack. The research team wanted to find out which type of diet worked better for reversing endothelial damage in heart attack patients.

Study details: Just over 800 patients with a heart attack history obtained endothelial testing that included measuring endothelium flexibility, called flow-mediated dilation (FMD). Better FMD means that there is better blood flow during stressful events or exercise. The researchers also measured the ability of the endothelium to produce cells that repair damage. These cells are called endothelial progenitor cells (EPCs).   

The patients were then equally divided into two diet groups for one year. One group was put on a low-fat diet and the other on a Mediterranean diet…

  • The low-fat diet consisted of 12% monounsaturated fatty acids (MUFAs), 28% fats and more than 55% carbohydrates. This diet featured a reduction in all fats, increased complex carbohydrates (like whole grains), low-fat dairy and avoidance of nuts, red meat, sweets and pastries.
  • The Mediterranean diet consisted of 22% MUFAs, 35% fats and less than 50% carbohydrates. It featured virgin olive oil, fruits and vegetables, and three weekly servings of fish, legumes and nuts. Patients were asked to cut back on meats—especially red meat—and to avoid margarine, butter and added sugar.

Results: At the end of one year, endothelial testing was repeated. Patients on the Mediterranean diet had doubled their FMD and improved their EPCs by over 60% compared with the low-fat patients. The research team concluded that the Mediterranean diet led to better endothelial function and repair and that the Mediterranean diet can be recommended as the best diet for reducing risk in patients with CHD.

Source: Study titled, “Mediterranean Diet and Endothelial Function in Patients with Coronary Heart Disease: An Analysis of the CORDIOPREV Randomized Controlled Trial,” by researchers at Maimonides Biomedical Research Institute of Cordoba, Spain, published in PLOS Medicine.