Study: Low-Calorie Diet Keeps Heart Young


ST. LOUIS - Joe Cordell was already health-conscious — exercising regularly and eating relatively well — when he stumbled upon a book four years ago that changed his life.



The book was by Dr. Roy Walford, a proponent of nutrient-rich, low-calorie diets. Cordell began limiting calories and almost immediately his already healthy heart rate, blood pressure and cholesterol numbers improved dramatically.

"I looked around one day a year later and said to my wife, 'Have I been sick in the last year or so?,'" recalled Cordell, now 47, a lawyer from St. Louis. "Four years down the road, I can count on one hand the number of times I've had even a cold. I require less sleep, I have more energy."

Researchers at Washington University in St. Louis on Thursday released findings of what they called the first-ever human study to demonstrate the cardiac benefits of a restricted calorie diet.

The findings, they said, confirmed earlier studies of mice and rats — a very low-calorie yet nutritionally balanced diet helps the heart age more slowly. Findings will be presented in the Jan. 17 issue of the Journal of the American College of Cardiology.

The study looked at the heart function of Cordell and 24 other members of an organization called the Caloric Restriction Society, all ages 41 to 64, and all of whom consume 1,400 to 2,000 nutritionally balanced calories per day. They were compared to 25 people who eat a typical Western diet, consuming 2,000 to 3,000 daily calories on average.

The result: Those limiting caloric intake had the heart functions of much younger people — typically about 15 years younger than their ages. Ultrasound exams showed members of the group had hearts that appeared more elastic than most people their age. Their hearts were also able to relax between beats in a way similar to hearts in younger people.

"This is the first study to demonstrate that long-term calorie restriction with optimal nutrition has cardiac-specific effects that (delay or reverse) age-associated declines in heart function," said Dr. Luigi Fontana, assistant professor of medicine and the study's principal investigator.

Dr. Art Labovitz, chairman of cardiology at Saint Louis University Medical Center, said the study reaffirms long-held beliefs about the benefits of a low-calorie diet.

"These are things that have pretty much become common sense and are ingrained in our culture," Labovitz said. "This is a reasonable diet and you would expect with a calorie-restricted diet that we're going to get a lot of secondary health benefits."

Research on mice and rats indicated that life span can be stretched by about 30 percent with stringent and consistent caloric restriction, researchers said. That research also suggested that restricting calories can help prevent cancer.

Heart attacks and strokes cause about 40 percent of all deaths in Western countries, researchers said. Cancer causes another 30 percent. Fontana said those deaths are attributable to "secondary aging," resulting from conditions such as high cholesterol, diabetes, high blood pressure and other often-preventable conditions.

While it has long been known that a healthy diet and exercise can reduce risks, the study suggests that caloric restriction combined with optimal nutrition can do even more.

Fontana said most participants in the study had parents, grandparents, brothers or sisters who suffered heart attacks or strokes. That meant it was unlikely their genetic makeup was a contributing factor in their unusually healthy hearts.

Previous studies by Fontana and his colleagues indicated people on very low-calorie diets had other benefits, such as blood pressure scores comparable to much younger people and a lower risk of developing diabetes.

"It's very clear from these studies that caloric restriction has a powerful, protective effect against diseases associated with aging," says co-investigator Dr. John O. Holloszy, professor of medicine.

"We don't know how long each individual will end up living, but they certainly have a longer life expectancy than average because they're most likely not going to die from a heart attack, stroke or diabetes. And if, in fact, their hearts are aging more slowly, it's conceivable they'll live for a very long time."

Fontana stressed that simply consuming less food is not the answer. Members of the study group favor a diet resembling a traditional Mediterranean diet, focusing on vegetables, olive oil, beans, whole grains, fish and fruit. They avoid the likes of refined and processed foods, soft drinks, desserts, white bread and other sources of "empty" calories.

"These people have very good nutrition," he said. "They eliminate calories by eating nutrient-dense foods."

Fontana and Holloszy say caloric restriction isn't for everyone. Instead, they recommend a moderate reduction in calories, combined with moderate, regular exercise.

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