Veggie Blog

In 1990 a small study reported that a strict program of diet and lifestyle changes could make clogged heart arteries narrower, not just stop them from getting worse. It made news around the world. The old version of this post described it in garbled language. Here is what the study actually found, what it did not prove, and what you can safely take from it today.

What did the study find?

The study was the Lifestyle Heart Trial, led by Dr. Dean Ornish and published in The Lancet in 1990. It was a randomized controlled trial, which is the best design for this kind of question. Twenty-eight patients with coronary artery disease were assigned to an intensive lifestyle program (a low-fat vegetarian diet, stopping smoking, stress management training and moderate exercise), and 20 to a usual-care group. After one year, the average narrowing of the arteries (percent diameter stenosis) had regressed from 40.0 to 37.8 percent in the lifestyle group and progressed from 42.7 to 46.1 percent in the usual-care group. Overall, 82 percent of patients in the lifestyle group had an average change toward regression. The abstract in PubMed gives all the numbers.

What did it not prove?

Be careful with this result. The study was very small, with only 48 patients, and it lasted one year. The program had several parts, including the diet, exercise, stress management and no smoking, so the study cannot say which part did the work. The old post said that the researchers could not tell how much of the improvement came from each change, and that is still true. The participants were also strongly committed to a demanding program, which is hard to match in everyday life. And the study does not mean that anyone can safely stop heart medicine. People with heart disease should keep taking prescribed medicines and ask their cardiologist before making big changes.

What do heart experts recommend today?

The National Heart, Lung, and Blood Institute (NHLBI) says that most heart attacks are caused by coronary artery disease, that your age, lifestyle habits and other medical conditions can raise your risk, and that more than 800,000 people in the United States have a heart attack each year, according to the CDC. It also says that heart-healthy living means understanding your risk, making healthy choices and taking steps to reduce your chances of heart disease. The usual advice includes eating a healthy diet, being physically active, not smoking, managing stress, and treating high blood pressure and high cholesterol. See the NHLBI page on heart-healthy living for details.

What can you do in practice?

You do not need a strict program to make a difference. Start with food: our posts on what you can do to lower your cholesterol and what cholesterol is and why too much is a problem explain the basics, and understanding your cholesterol numbers shows how to read a test. Add regular movement with the ideas in health and fitness: why exercise matters. Stress management also has a place, and our article on what the research says about yoga covers the evidence. Talk to your doctor about your own risk and about which of these steps suit you.

When is it an emergency?

Symptoms of a heart attack include chest and upper body pain, shortness of breath, dizziness, sweating and nausea. Women often have different symptoms. NHLBI says that if you think you or someone else may be having a heart attack, you should call 9-1-1 right away, because acting fast can save your life.