Some cardiologists believe that the protection afforded by the Mediterranean diet might be enhanced by drugs that lower blood-cholesterol levels. Studies suggest that the kinds of oils in the fat included in the Mediterranean diet may protect the heart against potentially fatal disruptions of heart rhythms and other causes of heart attacks. Many people who have had heart attacks are advised by their cardiologists to begin an exercise regimen in addition to changing their diet. The patients who consumed the Mediterranean diet enjoyed the food and continued to follow the diet after the experiment was concluded.
In a recent study of more than 400 North American men and women whose previous heart attack put them at risk for a second heart attack, about half were told to switch to a "Mediterranean-type diet" -- one rich in fish, vegetables, olive oil, and grains -- while the other half were advised to eat a more traditional "Western" diet but to limit their fat intake. Those following the Mediterranean diet were significantly less likely than those in the other group to have a second heart attack. But the Mediterranean diet includes a fair amount of fat from fish and olive oil, so the research suggests that a diet may not have to be extremely low in fat in order to protect the heart.
Which one of the following, if true, most strengthens the argument?