About the recent French study on diet and heart disease
(NYT 03-23-99), Jane Brody goes on to say ...
The latest study, published last month in Circulation, the journal of the American Heart Association, is a four-year follow-up of more than 400 men and women in France, all of whom had already suffered one heart attack and therefore were at risk of another. About half the participants were told to switch to a Mediterranean-type diet rich in fruits, vegetables, cereals, fish and beans, and the other half were advised to eat a more traditional Western diet that was relatively low in fat, saturated fat and cholesterol.
Those following the Mediterranean diet were 50 percent to 70 percent less likely than the comparison group to develop recurrent heart disease, including fatal and nonfatal heart attacks.
Fat as a Heart Protectant
Perhaps the most surprising, and gastronomically pleasing, feature of the dietary scheme that has emerged from this research is that the diet may not have to be low in fat to protect the heart. Rather than insisting, as does Dr. Dean Ornish, that no fat be added to food and that all fat-containing animal foods be avoided, advocates of the Mediterranean diet include a fair amount of fat, nearly all in the form of oils: olive oil, nut and seed oils and fish oil.
However, meat in the traditional Mediterranean diet is only a sometime thing, used more as a condiment than as the main ingredient in meals. Instead, the diet features lots of fruits and vegetables, legumes and nuts and all manner of grains (bread, pasta, rice, bulgur and the like), often cooked and/or seasoned with olive oil.
The predominant animal foods are fish, yogurt and cheese (usually low-fat feta). Wine is typically consumed in moderation with meals. A featured item of Greek meals, for example, is a large salad of tomatoes, cucumbers, olives, onions and feta cheese, dressed with vinegar and olive oil and eaten with bread.
In the newly published study, conducted by Dr. Michel de Lorgeril and colleagues in Lyon, France, 30 percent of calories in the experimental Mediterranean diet came from fat and 8 percent from saturated fat, compared with 34 percent fat calories and nearly 12 percent saturated fat calories in the other group's diet. Cholesterol intake averaged 212 mg a day on the Mediterranean diet; on the control diet, 312 mg.
The levels of fats and cholesterol reached in the Mediterranean diet approached those recommended by the American Heart Association for people who have heart disease or high levels of cholesterol in their blood, whereas the comparison group's diet closely resembled that of typical Americans, half of whom die of heart disease.
The Mediterranean diet group also consumed more dietary fiber, antioxidants and B vitamins found in fruits and vegetables, all of which may slow the arterial damage that precedes heart disease.
Role of Fatty Acids
What is so special about olive oil or, for that matter, the oils in nuts and seeds, like walnut oil, canola oil and flaxseed oil? They are, first of all, unsaturated oils that do not raise blood levels of cholesterol. And they are rich in a kind of fatty acid called alpha-linolenic acid, an omega-3 fatty acid that is found only in plants and is an essential nutrient in the human diet.
Along with fish oils, which are also rich in omega-3 unsaturated fatty acids (eicosapentaenoic acid, or EPA, and docosahexaenoic acid, or DHA), these oils have several effects in the body that would be expected to prevent or reduce coronary heart disease. Studies in animals and people have pointed to such effects as a reduced risk of blood clots, prevention of abnormal heart rhythms, less inflammation and clogging of blood vessels by deposits of fat and cholesterol and prevention of sudden cardiac death (this last effect is linked mainly to fish oils).
As might be expected, in the Lyon study, those participants who had higher blood levels of omega-3 fatty acids had a lower risk of developing a recurrent heart attack or other cardiac problems. This finding should not be interpreted to mean that blood levels of cholesterol are unimportant; countless studies have clearly demonstrated that they are. The higher the cholesterol level, the greater the risk of heart disease.
In fact, Dr. de Lorgeril and colleagues suggested that the protection afforded by the Mediterranean diet might be enhanced by drugs that lowered blood levels of cholesterol. But, according to Dr. Alexander Leaf, professor emeritus of clinical medicine at Harvard University Medical School, the Lyon study indicates that "there are other powerful risk factors within the realm of diet that must be considered if we are to achieve maximal dietary benefits in reducing this No. 1 cause of mortality in the world today."
One interesting finding of the Lyon study was that although the project was officially terminated after 27 months (the benefits of the Mediterranean-type diet were so drastic that the researchers concluded it would be unethical not to give the comparison group a chance to go on it), most of the participants who had been in the experimental group continued to follow the diet. In other words, the diet was well-tolerated and probably enjoyed.
Don't Forget Fish
If you are serious about wanting to avoid a heart attack, or a worsening of heart disease, numerous studies have strongly indicated that you'd be wise to eat fish at least once or twice a week. Here is a quick summary of some of the most telling findings:
In a study in Seattle and surrounding suburbs of 334 people who suffered a cardiac arrest compared with 493 people who had not, eating one fatty fish meal a week was associated with a 50 percent to 70 percent lower risk of a fatal heart attack, according to a report by Dr. David S. Siscovick and colleagues at the University of Washington. This finding strongly suggests that eating fish can prevent potentially fatal disruptions of heart rhythms, an effect that has been demonstrated in laboratory animals given fish oils.
A British study found that people who regularly ate fish, especially fatty fish, were less likely to suffer heart attacks. The researchers, writing in the British Medical Journal, suggested that fish oils reduced the thickness and stickiness of the blood, which in turn meant less chance that a blood clot would form and precipitate a heart attack.
A 30-year study of 1,800 men in Illinois showed that men who
consumed one or two servings of fish a week (about 7 ounces) had a
significantly lower risk of suffering a fatal heart attack. The lead
researcher, Dr. Martha Daviglus of Northwestern University Medical
School, concluded, "The good news is that small amounts of fish,
amounts all of us can easily fit into our diets, may make a
difference."