Heart disease and the Mediterranean diet
LYON, FRANCE. The Lyon Diet Heart Study began in 1988 and is designed to explore the benefits of a Mediterranean-type diet in preventing further cardiovascular complications after suffering a first heart attack. The findings of the study were first reported in 1994 and showed that heart attack survivors who followed the Mediterranean diet were 70 per cent less likely to die from cardiovascular causes (within the 27-month long study period) than were members of the control group who followed the so-called prudent Western-type diet promoted by the American Heart Association and others. The French researchers now report that the benefits of the Mediterranean-style diet lasted well beyond the original 27 months. After an average follow-up of 46 months the patients in the Mediterranean diet group still had a 72 per cent lower risk of cardiac death or of suffering another heart attack. The overall rate of death (from all causes) in the Mediterranean diet group was found to be less than half of that in the control group (prudent Western-type diet). The researchers believe that it is the relatively high content of alpha-linolenic acid and the low content of linoleic acid, which is primarily responsible for the benefits of the Mediterranean diet. Canola, flaxseed, and soy bean oils are particularly good sources of alpha-linolenic acid. Somewhat surprisingly, the researchers found no protective effects of such commonly prescribed heart drugs such as beta-blockers, calcium channel blockers, and ACE inhibitors. Aspirin usage, however, was associated with a protective effect.
Dr. Alexander Leaf, MD of the Harvard Medical School, in an accompanying editorial, points out that the Mediterranean diet by itself is more effective in preventing cardiovascular complications than are any of the cholesterol-lowering drugs. This does not mean that high cholesterol levels are not a potent risk factor for heart disease, but rather that there are other dietary factors which may be more important. Dr. Leaf strongly advocates the lowering of linoleic acid content and the increase of alpha-linolenic acid in the diet. He has found that alpha-linolenic acid has potent antiarrhythmic effects. He also points out that our forebears consumed a diet with a 4:1 ratio of linoleic to linolenic acid; this ratio today is more life 15:1.