By: Thomas Pickering, MD, DPhil, FRCP, Director of Integrative and Behavioral Cardiology Program
of the Cardiovascular Institute at Mount Sinai School of Medicine, New York.

The 'Mediterranean' diet, which is rich in fruits and vegetables and low in saturated fat and red meat, has frequently been advocated for the prevention of heart disease. Most of the evidence for this comes from observations that people living in countries where such diets are prevalent are at low risk of getting heart disease. The theory has been tested in only one human study, the Lyon Diet Heart Study performed in France. In this study 605 people (nearly all men) who had survived a first heart attack were randomly allocated to eat one of two diets. One was a diet similar to the step 1 diet of the American Heart Association (which restricts the intake of saturated fat to 30% of the total calories and cholesterol to 300 milligrams a day), the other an experimental Mediterranean-type diet. The latter was characterized by more bread and cereals, more fresh fruit and vegetables, more fish, less meat (and beef and pork replaced by chicken); butter or cream were replaced with a canola-oil based margarine which was rich in oleic and alpha-linolenic acids. Canola and olive oil were used for salads and food preparation.

During the one to five years of follow-up, the patients eating the Mediterranean diet had fewer deaths from cardiovascular disease (1%, versus 5% in the patients eating the regular diet). These findings were published in 1994. A second report on the rate of development of cancer in the study participants now follows. The patients eating the Mediterranean diet had less than half the number of new cases of cancer, and the overall death rate (from all causes) was also reduced by about half.

Doctor's comments

The finding that a Mediterranean diet may prevent cancer was unexpected and was not one of the original goals of the study. It does, however, make sense. Vegetables contain a number of antioxidants (which protect against cancer) and there is other evidence that eating a lot of vegetables is associated with less cancer. The Mediterranean diet is also rich in omega-3-fatty acids, which could have a protective effect.

Where it was published

de Lorgeril M and colleagues. Mediterranean dietary pattern in a randomized trial. Prolonged survival and possible reduced cancer rate. Archives of Internal Medicine1998;158:1181-1187.