By Gordon A. Ewy, MD
UA Sarver Heart Center Director

Since 40 percent of Americans, and 75 percent of Americans with diabetes, die from complications of cardiovascular diseases, it is critical to know how to prevent cardiovascular disease, namely heart and valvular disease and stroke.

When considering nutrition one has to be concerned about both quantity and quality. Let's start with quantity. Mortality increases progressively as one's body weight is more or less than ideal. Volumes have been said about diets: Atkins, Ornish,Pritiken, Zone, American Heart Association, low-fat, etc. But like exercise, after all is said and done, much more is said than done! Witness the fact that in the United States, the incidence of obesity has increased dramatically over the past decade. During the 1990s, the number of overweight and obese people in this country increased by 55 percent! Since our "gene pool" didn't change over this short time span, the problem is an excess of caloric intake over caloric expenditure. Yes, calories do count!

Currently, one-fifth of the U.S. population is obese. What is obesity? The scientific definition of an obese person is one who weighs 20 percent or more than ideal body weight or who has a body mass index (BMI) of 30 or greater (click to view Table 1). The BMI takes into account one's height as well as weight.

Meanwhile, almost two-thirds of American men and three-fourths of American women are dieting to lose or maintain weight. Unfortunately, only one-fifth of American dieters are using the recommended combination of eating fewer calories while getting at least 15 minutes of leisure-time physical activity per week. Are there diets that prevent coronary artery and other vascular diseases? The Ornish diet might be effective. It is a vegetarian diet that contains 10 percent fat, 5 milligrams of cholesterol and is combined with stress reduction and modest exercise. People on the Ornish diet must carefully shop for packaged food with nutrition labels that indicate 0 percent, 0 percent and 0 percent - no fat, no saturated fat and no cholesterol . This diet calls for such marked changes that most Americans are unwilling or unable to follow it for any length of time. On the Ornish diet, it's nearly impossible to eat out or have guests over for meals. The first questions I ask people who say they are on the Ornish diet is, "How much weight have you lost?" The average sustained weight loss of people on the Ornish diet is 21 pounds. Most people who think they are on the Ornish diet are probably not.

In contrast, the Atkins diet, which is effective for weight loss, allows steak, bacon, butter and selected vegetables - but no carbohydrates! The Atkins diet at times produces impressive weight loss. However, once carbohydrates are reintroduced into the diet, the weight rapidly returns.

Studies have shown that it is better to be overweight than to be on a series of diets with repeated weight loss and weight gain. The long-term cardiovascular effects of the Atkins diet are unknown.

To prevent cardiovascular disease, fish and marine oils should be an important component of the diet. Diets high in fish have been shown to be protective in both observational and secondary prevention trials. Coronary heart disease is lowest with consumption of 35 or more grams (about 1.25 ounces) of fish per day. Fish oil capsules, in doses of 1 gram ofn-3 polyunsaturated fatty acids (PUFA) daily, given to patients who survived a heart attack, significantly decreased mortality. This recently-completed Italian GISSI Trial, published in the New England Journal of Medicine, confirms other trials that show the benefits of diets high in fish or fish oils.

Our recommendation is that you don't diet, but that you carefully select the food you eat. Dieting usually doesn't work because "willpower" lasts about three weeks - and is soluble in alcohol. Some of the diet programs, with their weekly meetings, are ineffective because all they talk about is food! You leave the meetings thinking about food, and guess what - you are starved!

A heart-healthy way of eating includes five to seven servings of fruits and vegetables a day. It has been said that the average American consumes a little less than two servings of fruits and vegetables per day, and that is only if you count french fries as a vegetable!

Portion control is an important key. You probably can have a lean steak or a dessert every once in a while as long as it is a very small portion.

Some people with very low fasting blood cholesterol levels still get coronary and other forms of cardiovascular disease. Most such people, because they have low blood cholesterol levels, eat diets high in saturated fats and other animal products. Patients' blood fats (cholesterol and triglycerides) are measured in the "fasting" state. Most of the day, we are not in a fasting state and therefore a "fasting" cholesterol and triglycerides may not give a true reflection of the patient's usual lipid state. A lot of saturated fats in the diet are possibly deleterious to the patient with low cholesterol as well. If you have, or if there is a family history of, cardiovascular disease, a low fasting cholesterol level is not a reason to not eat properly.

Of course there may be other reasons why patients with low blood concentrations of LDL, or bad cholesterol, get vascular disease, including elevated blood homocysteine concentrations, elevated levels of an abnormal form of bad cholesterol known as "lipoprotein little a," or LP(a),and other factors yet to be discovered as abnormalities. These are currently the focus of intense research.

The ideal diet appears to be the Mediterranean diet which uses olive oil as the main source of fat and is high in fruits, vegetables, nuts and fish and is low in saturated fat and other animal products.

But remember - to lose weight, the ideal diet must be limited in calories and combined with exercise!