Halt heart disease with a plant-based, oil-free diet

Harvard Heart Letter

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Diets that emphasize vegetables, whole grains, and legumes may help slow or even reverse heart disease.

A new study suggests you can. But a more lenient eating pattern may be easier to follow and just as effective.

The idea that a low-fat, strict vegetarian diet may reverse heart disease is hardly new. First popularized by Dr. Dean Ornish more than two decades ago, these diets shun most animal-based foods, such as meat, milk, and eggs, and limit added fats. Small studies suggest that this eating pattern can shrink the amount of cholesterol-clogged plaque in your arteries, the main culprit in cardiovascular disease.

The latest evidence comes from a study published in The Journal of Family Practice last summer led by Dr. Caldwell B. Esselstyn, Jr., another long-time proponent of plant-centric diets. The study, which included 198 people with documented cardiovascular disease, found that 177 were able to stick to the diet for an average of almost four years. During that time, only one person had an event (a stroke) that was deemed a recurrence of the disease. In contrast, 13 of the 21 people who didn't stick to the diet experienced a cardiovascular event.

How do these results stack up against other heart-healthy diets? If you have heart disease, should you consider going vegan?

Less meat, more vegetables

"There's no question that diet has a huge impact on heart disease," says Dr. Walter Willett, professor of epidemiology and nutrition at the Harvard School of Public Health. The study diet features elements that have been closely linked to a lower risk of heart disease: namely, less red meat, less refined starches and sugars, and more fruits and vegetables, says Dr. Willett.

But in this study, it's impossible to tease out which elements are responsible for the observed benefits. And one aspect of the diet—avoiding all added oils and even high-fat plant foods like avocados and nuts—isn't necessarily helpful, Dr. Willett notes. "There's lots of evidence that unsaturated fat lowers blood lipids such as cholesterol and reduces heart disease," he says. What's more, a low-fat diet is, by definition, a high-carbohydrate diet. These diets tend to promote the release of insulin, the hormone that regulates blood sugar levels. In people who aren't very physically active, high insulin levels send a signal that it's time to store fat, which can lead to weight gain.

Mediterranean diets: The strongest evidence

Without the flavor and sense of satiety that comes from fat, a low-fat vegan diet can be tough to follow. As the study authors admit, the participants were "self-selected and very determined." That points out another limitation of the study: it didn't randomly assign people to different diets and track their results, which is the gold standard for research studies.

The best evidence on how diet affects people with heart disease comes from the Lyon Diet Heart Study, which found that a Mediterranean-style diet cut heart attacks and deaths by 70% compared with a traditional American Heart Association diet, says Dr. Willett. The Mediterranean-style diet emphasized fish, poultry, vegetables, beans, olive oil, and nuts and included only minimal amounts of meat, butter, and cream.

This type of less-restrictive diet tends to be easier for people to maintain, Dr. Willett notes. Since it hasn't been compared head-to-head with a vegan diet, it's hard to say if one might lead to better outcomes. Still, both are good options. You can try one, and go back and forth, suggests Dr. Willett. But, he adds, "Staying on the average American diet is not a good plan."

The heart disease-reversing diet: What to eat, what to avoid

With a focus on plant-based foods, this diet prohibited not only animal-based foods but also oils, fats, refined carbohydrates, and sweets.

Allowed

Not allowed

  • Whole grains

  • Legumes (beans, lentils, and peas)

  • Vegetables

  • Fruits

  • Daily multivitamin and vitamin B12 supplement *

  • Flaxseed **

  • Oils and processed foods containing oils

  • Meat, poultry, and fish

  • Dairy products and eggs

  • Refined carbohydrates (includes white rice and bread, pasta, crackers, cookies, cakes, and muffins made with white flour)

  • Avocados and nuts

  • Foods and beverages containing sucrose or fructose; syrup, and molasses

  • Fruit juice

  • Caffeine

*B12 is found only in animal-based foods so people who exclude those foods are often advised to take this supplement. ** This provides omega-3 fatty acids, a necessary nutrient. *B12 is found only in animal-based foods so people who exclude those foods are often advised to take this supplement. ** This provides omega-3 fatty acids, a necessary nutrient.