It was Dean Ornish, a professor of medicine at the University of California–San Francisco and founder of the Preventive Medicine Research Institute, who first showed that heart disease can actually be reversed, without drugs or surgery, by radically restricting fat intake, getting more exercise, and easing stress. The Ornish menu stops just short of veganism; nonfat dairy and egg whites are allowed. But it doesn't allow much wiggle room. Only 10 percent of calories can come from fat, very little of it saturated. Most foods with any cholesterol or refined carbohydrates, oils, excessive caffeine, and nearly all animal products are banned. Fiber and lots of complex carbohydrates are emphasized.
This regimen, combined with stress management techniques, exercise, social support, and smoking cessation, formed the basis of a landmark study of 48 heart disease patients published in 1990 in the Lancet. The program followers showed artery blockages receding after one year and continuing to do so at the five-year mark. The condition of control group members worsened at both points. In Caldwell Esselstyn's research on more than a dozen patients with advanced coronary disease, those who adopted his plant-based program also demonstrated a halting or reversal of the disease after five years.
Today, patients at hospitals and clinics nationwide can follow Ornish's Program for Reversing Heart Disease, which is covered by Medicare and private insurance companies. Among the nearly 4,000 people who had tried the program in Pennsylvania, Nebraska, and West Virginia by last fall, the average patient lost 13.3 pounds in the first 12 weeks and 15.9 after a year. There were significant drops in blood pressure, total cholesterol, triglycerides, and LDL cholesterol. Patients also reported less depression and hostility, the emotions most strongly linked with heart disease. And nearly 97 percent experienced improvements in the severity of their chest pain after a year.
Since those early days, the Ornish approach has evolved into a "spectrum" plan. He categorizes food into five groups from most (group 1) to least (group 5) healthful. It's the difference, for example, between whole-grain bread and biscuits, between soy hot dogs and pork or beef ones. The heart-healthy choices are at one end, and the choosing is up to you.
Despite all the advantages, vegan diets aren't a no-brainer move. There are downsides, from potential health risks to the challenge of sticking to such a restrictive eating plan. "Vegan diets are difficult to manage, and they're nutritionally incomplete," says Marion Nestle, a professor of nutrition at New York University and coauthor of Why Calories Count. "So you have to compensate for that in some way."
Since dairy is out, vegans often don't get enough calcium, for example. And in a report on the health effects of a vegan diet published in the American Journal of Clinical Nutrition in 2009, researchers warned that vitamin D, vitamin B12, and zinc are often lacking. One study showed, for instance, that more than half of vegans tested were deficient in vitamin B12, which is important for metabolism and is found only in animal products. These people were at risk for mental health problems, fatigue, trouble concentrating, decreased brain volume with aging, and irreversible nerve damage. But tofu, calcium-fortified juice and soy milk, bok choy, broccoli, kale, and okra all offer a plant-based source of calcium. Vitamin D- and vitamin B12-fortified products are available, too. And good sources of zinc include nuts, seeds, cooked beans, wheat germ, and cooked grains.
Vegans are often low as well in the omega-3 fatty acids EPA and DHA, important for brain, eye, and cardiovascular health and readily available in fish like salmon, tuna, shrimp, and sardines. "It's not true that you can get all the essential fatty acids you need from flax seeds," says registered dietitian Katherine Beals, an associate professor in the division of nutrition at the University of Utah, who worries about excluding salmon. "Vegetarian diets are demonstrably healthier than the standard American diet, but when you exclude all animal products, it gets questionable," Nestle says.