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to Menu Page~For the most severe cases of heart disease, surgeons remove veins (usually from the legs) and use them to "detour," or bypass, around the clogged arteries of the heart. Even though people who undergo bypass operations experience a reduction in chest pain, the benefits of this surgery, which costs approximately $30,000, often wear off (Myrmel, 1993).
Researchers have known for several decades that a proper diet may prevent the onset of cardiovascular disease. However, once an individual develops this chronic condition, surgery and drugs have been considered the only available methods in mainstream medicine for trying to reverse its effects (Califf et al., 1989). Only recently has diet been considered an alternative to drugs and surgery for treating cardiovascular disease. In the mid-1970s, Nathan Pritikin began using an extremely low-fat, high-fiber diet along with exercise to treat heart disease patients and showed that he could lessen their clinical symptoms. Then in the late 1980s, San Francisco physician Dean Ornish set out to do the same. However, Ornish was armed with a powerful new tool: the angiogram, which is an interior picture of patients' blood vessels. Using "before" and "after" angiograms, Ornish was able to see how changes in diet and lifestyle affected the status of the blockage, or plaque, in the artery. The Pritikin ~and Ornish diets are described below.
Pritikin diet. The diet is named after the man who developed it, Nathan Pritikin, who had been told by his cardiologist that he was at great risk of death from myocardial infarction. Therefore, he patterned for himself a diet modeled after a vegetarian diet followed by the people of Uganda, who were shown to be essentially free from death by heart attacks (Martin, 1991). In the late 1960s, after a few years on this diet, Pritikin decided that it had saved his life and founded his clinic in Santa Monica to treat cardiac patents.
The Pritikin diet is basically vegetarian, high in complex carbohydrates and fiber, low in cholesterol, and extremely low in fat (less than 10 percent of daily calories). The Pritikin diet also requires 45 minutes of walking daily. Although this diet and exercise program can be followed completely on an outpatient basis, the Pritikin Longevity Center in Santa Monica recommends that patients attend a 26-day program to learn how to prepare their new type of meals and practice new daily exercise and living habits.
~Ornish diet. This diet was developed by Dean Ornish, M.D., an assistant clinical professor of medicine at the University of California, San Francisco. The Ornish diet is basically vegetarian, allowing no meat, poultry, or fish, and permitting only the white of eggs. Also, no nuts, caffeine, or dairy products, except a cup a day of nonfat milk or yogurt, are allowed, and no oil or fat is permitted--not even for cooking. Two ounces of alcohol a day are allowed. Providing an average of about 1,800 calories a day, the diet provides 75 percent of its calories from carbohydrates and less than 10 percent from fat (Ornish, 1990). The American Heart Association's recommended adult "prudent diet" calls for total fat of less than 30 percent, which Ornish feels is not really low enough, even for healthy adults, but especially not for people trying to reverse atherosclerosis (Ornish, 1990). Ornish provides his patients all their lunch and dinner meals, precooked, packed in Tupperware, and handed out a week's worth at a time.
In many ways, the Ornish diet is similar to the Pritikin diet. Both are basically vegetarian (although Pritikin does allow 85 grams of chicken or fish per week), high in complex carbohydrates, high in fiber, low in cholesterol, and extremely low in fat (less than 10 ~percent of daily calories). However, Ornish's program--run on an outpatient basis--calls for stress reduction practices in addition to the diet and emphasizes emotional social support systems, particularly between members of the group. It also requires daily stretching and an hour's walk three times a week.
Research base. The following is an overview of the available research on these two ultra-low-fat dietary regimens.
Pritikin diet. In a study of men taking the Pritikin 26-day course, all 21 participants reduced their cholesterol level, 19 reduced their triglyceride level, and 16 had a reduction in their estradiol level (Rosenthal et al., 1985).
In another study assessing the effectiveness of the Pritikin diet and exercise program on cardiovascular hemodynamics, 20 subjects were divided in two groups (active/treatment and control). These data were compared to a group of 10 healthy individuals not involved in the program. Hemodynamic parameters were collected at admission and at the end of the ~26-day program. In obese and hypertensive subjects not on medication who followed the Pritikin program, the cardiac index increased by 10 percent, mean arterial pressure decreased by 5 percent, and the systemic vascular resistance index decreased by 18 percent. Little change was seen in controls. There also was an improvement in ventricular performance (Mattar et al., 1990).
The Pritikin diet has also been studied in connection with adult-onset diabetes mellitus and peripheral vascular disease. Studies suggest that it may show promise in controlling newly diagnosed cases of adult-onset diabetes without drugs. One study (Barnard et al., 1982) evaluated 60 patients who had completed the Pritikin 26-day program. Of the 23 who were taking oral hypoglycemic agents upon entry, all but 2 were off medication by the end of the program. Of the 17 patients who were taking insulin, all but 4 were off medication at discharge. Two of those 4 had their insulin reduced by 50 percent, while the remaining 2 had no major change in their insulin dosage. Fasting blood glucose levels were significantly reduced in all patients; serum cholesterol levels were similarly reduced, as were triglyceride levels. The group as a whole lost an average of 4.3 kg of body weight and achieved 40.5 ~percent of their desired weight loss. Maximum work capacity increased significantly, while daily walking increased from approximately 11.7 minutes a day to approximately 103 minutes.
In another study, University of California, Los Angeles (UCLA) investigator Dr. James R. Barnard put 650 diabetic patients on the Pritikin diet. After 3 weeks, some 76 percent of the newly diagnosed diabetics, along with 70 percent of those on oral agents, had normal glucose levels (Barnard et al., 1992). However, only 40 percent of those already receiving insulin responded to the diet. According to Barnard, muscles, which may become severely insulin resistant during drug treatment, respond to exercise and a low-fat diet. In contrast, drugs may eventually weaken the pancreas while failing to reduce physically and financially devastating vascular complications (e.g., deterioration of eyes and kidneys).
Ornish diet. In what is now known as the Lifestyle Heart Trial, in the late 1970s and early 1980s Ornish conducted a series of trials in which patients with confirmed heart disease were placed on a diet and lifestyle modification program. In the first study, after 30 days ~people reported a substantial reduction in frequency of angina (heart pain), and many were pain free. Cholesterol levels were down about 20 percent, and high blood pressure was reduced (Ornish et al., 1979). In a followup study in the early 1980s, Ornish reported that 30 days of his regimen were enough to improve blood flow to the heart in some patients and that patients could exercise almost 50 percent more, on average, than they could before beginning the treatment (Ornish et al., 1983).
Finally, in a prospective, randomized, controlled trial to determine the effectiveness of his program over a longer time, Ornish and his colleagues put 28 men and women whose arteries were partially blocked on his program for a full year. Twenty other patients were assigned to a "usual care" group. After 1 year, without the use of lipid-lowering drugs, patients in the experimental group (i.e., receiving the Ornish treatment) reported a 91-percent reduction in the frequency of angina, a 42-percent reduction in the duration of angina, and a 28-percent reduction in the severity of angina. In contrast, control group patients reported a 165-percent rise in frequency, a 95-percent rise in duration, and a 39-percent rise in severity of angina (Ornish et al., 1990).~Patients in the experimental group also showed a significant overall regression, or reduction, of coronary atherosclerosis (blocked arteries) as measured by angiograms. In contrast, patients in the usual care group had a significant overall progression, or worsening, of their coronary atherosclerosis. This finding led Ornish to conclude that the conventional recommendations for patients with heart disease, such as a 30-percent fat diet, are not sufficient to bring about an improvement in many patients.
Ornish has never tested separately each component of his multifaceted program, so it is impossible to be sure which component contributed most to the improvements. If it was the dietary regimen that led to the improvements, it is a regimen that most Americans would have a hard time following, admits Ornish (Schardt, 1993). However, some researchers believe that it does not take such a radically restricted diet to start reversing the effects of heart disease. In a study in Germany, 56 men suffering from angina caused by partially blocked arteries were placed on a reduced-fat diet (less than 20 percent of calories from fat, 7 percent of calories from saturated fat, and 200 mg of cholesterol a day). As in the Ornish program, they also participated in an exercise program. After a year, angiograms showed ~that the blockages in 32 percent of the men on the low-fat diet had improved, compared with just 17 percent in the control group (Schuler et al., 1992).
In addition, in the late 1980s, researchers in Britain placed 26 men with partially blocked arteries and elevated blood cholesterol on carefully monitored diets and reduced their fat intake to 27 percent of calories--about three-fourths of what the average American eats. The diet's saturated fat and cholesterol amounts also were substantially less than most Americans eat, while its fiber content was slightly higher. Over the next 3 years, the men on the fat-restricted diet suffered only one-third as many deaths, heart attacks, and strokes as men in the control group--who were not told what to eat, and whose diets were not monitored (Watts et al., 1992). Furthermore, angiograms showed that the openings in the arteries of 38 percent of the men who changed their diets became slightly larger.