Individuals who ate a Mediterranean diet were 50 to 70 percent less likely to suffer a repeat heart attack than those on a “Western” diet, according to a study in the February 2000 issue of Circulation: Journal of the American Heart Association.
The study, conducted by researchers in France, monitored the death rates among more than 600 men and women who had a first heart attack.
Michel de Lorgeril, M.D., who headed the research project, called the Lyon Diet Heart Study, says, “By making some simple dietary changes that are easy to understand and easy to follow, a person can improve his or her chances of avoiding a second heart attack and having a better quality of life.
“Results of the study are not surprising as they rather confirm previous population studies showing that the Mediterranean population may be relatively protected from coronary heart disease because of the foods they eat,” says de Lorgeril.
The Mediterranean diet reported in this trial is so named because it is similar, but not identical to that followed by people living near the Mediterranean Sea. The diet is rich in fruits, vegetables, cereals, fish and beans.
At the end of the 46 months of follow-up, 204 control subjects eating a Western diet and 219 experimental subjects participated in the final examination. At this time body mass index (a measure of body fatness), blood pressure and blood cholesterol levels were quite similar between the two groups. About 18 percent of both groups continued to smoke.
Despite the similarities in risk factors, the group following the Mediterranean diet had a 50-70 percent lower risk of recurrent heart disease determined by the three combinations of outcome measures. They were cardiac death and non-fatal heart attacks; cardiac death and non-fatal heart attack plus unstable angina (severe chest pain at rest), stroke, heart failure, pulmonary or peripheral embolism (blood clots in the lung or other parts of the body); and all of these plus events that required hospitalization.
Dietary information was also collected at the final visit. Unfortunately, only 83 individuals, about 40 percent of the control diet, and 144 individuals, or about 75 percent of the Mediterranean diet group, provided dietary information. Patients in the control diet group received dietary counseling only from their attending physician in contrast to those on the Mediterranean who were given instructions by the investigators.
Dietary intake in the control group was well above the American Heart Association Step I guidelines that recommend individuals eat less than 30 percent of their total calories from fat and less than 10 percent from saturated fat. The AHA recommends the Step II diet for individuals who have had heart disease or who have blood cholesterol levels of 240 milligrams/deciliter (mg/dl) or higher. The Step II diet recommends that individuals limit their saturated fat intake to less than 7 percent of total calories and no more than 200 mg of dietary cholesterol per day, while keeping total fat intake to less than 30 percent of calories or even lower.
The control diet group averaged almost 34 percent of total calories from fat and almost 12 percent of total calories from saturated fat. The Mediterranean diet averaged 30 percent of total calories from fat and 8 percent of calories from saturated fat. While there was tremendous variation in daily dietary cholesterol within both groups, the control group averaged 312 mg and the Mediterranean group averaged 212 mg a day .
The individuals on the Mediterranean diet consumed more oleic and alpha-linolenic fatty acids but less linoleic than the control group. Oils high in alpha-linolenic or “omega-3” fatty acids are found in high amounts in plants (canola) and certain nut oils whereas linoleic or “omega-6” fatty acids are high in soya and sunflower oils. Dietary fiber intake was about three grams higher in the Mediterranean group than the control group suggesting a slightly higher intake of fruits and vegetables and whole grain products, providing large amounts of antioxidant vitamins and trace elements.
The study also found that high blood pressure, elevated cholesterol and leukocytes, a type of white blood cells, were all associated with recurrent heart attacks.
According to Robert Eckel, M.D. chairman of the American Heart Association’s Nutrition Committee, “In general, the study suggests that patients diagnosed with cardiovascular disease can significantly reduce the risk of dying or having another heart attack by following the AHA’s Guidelines for Secondary Prevention, which include the Step II diet, other prudent lifestyle behaviors and the use of aspirin and other medications prescribed by their doctors. The fact that levels of LDL cholesterol were similar between the two diet groups and far above those established by the National Cholesterol Education Programs for patients with coronary heart disease suggests that additional benefit may have ensued in both groups with additional cholesterol-lowering drugs.”
In an editorial accompanying the journal article, Alexander Leaf, M.D., Jackson Professor of Clinical Medicine Emeritus at Harvard University Medical School, says, “One main message of the Lyon study is that the polyunsaturated oils (the omega-3) contained in the Lyon diet may be helpful in preventing second heart attacks.” In the study population, higher plasma (blood) levels of omega-3 fatty acids were associated with a lower risk of a recurrent heart attack and other heart-related problems.