Study Finds Lower Salt Intake May Be Beneficial for Everyone

For years, scientists have been arguing over whether to recommend to all patients--even those without hypertension--that they reduce salt in their diets.

The National Institutes of Health hopes to unambiguously end the debate today when it presents a study that suggests lowering blood pressure is good for everyone. In recent years, some researchers have questioned blanket recommendations that everyone could benefit by lowering salt intake, arguing that it would have no effect on those who do not have hypertension and might possibly even be dangerous.

So NIH researchers stressed that, unlike earlier studies, this one had made a concerted effort to broaden its reach, cutting across racial and risk categories.

The study, to be presented at a meeting of the American Society of Hypertension in New York, looked at the effect of salt on blood pressure among a diverse group of Americans, including men, women, young, old, white, African American and those with and without hypertension. And researchers looked at the salt factor in combination with two different kinds of diets: one healthy and the other not so healthy.

“The effects were quite substantial, even if you don’t have high blood pressure,” said Dr. Eva Obarzanek, one of the lead researchers.

“This finding should answer the question,” agreed Dr. Claude Lenfant, director of NIH’s Lung and Blood Institute, which sponsored the study.

But Dr. Michael H. Alderman, former president of the Hypertension Society and one of the most vocal critics of the edict that all patients should lower salt intake, was not convinced.

“If lowering blood pressure a little bit could be done at no cost, that would be a wonderful thing, but I’m not sure that is the case,” said Alderman, a professor of medicine and epidemiology at Albert Einstein College of Medicine in New York City.

Alderman said that reducing salt can cause irregularities in heart rhythms and cardiac cell growth and can interfere with the body’s response to insulin.

Further, he argued, it has not yet been demonstrated that lower blood pressure actually ends up producing fewer heart attacks and strokes and a longer life span.

“The low-sodium argument is a very rational argument, but I’d like to see if people are really better off as a result,” he said.

Obarzanek, a nutritionist at the institute, insisted that no study has found “any adverse effects of moderate reduction in sodium.”

She argued that the link between high blood pressure and increased risk of stroke and heart attack is not in dispute.

“We know that lowering sodium lowers blood pressure,” she said. “Why wouldn’t you make the leap?”

About 50 million adult Americans suffer from hypertension, with only about 68% aware of their condition. Hypertension is a known risk factor for heart and kidney disease and stroke.

Americans typically eat about 4,000 to 6,000 milligrams of salt a day, which is two to three teaspoons and twice the amount currently recommended by health officials.

Current recommendations urge that salt consumption be kept to a maximum of 2,400 milligrams. Obarzanek said that the findings may prompt health officials to further lower the recommended amounts, perhaps to 1,500 milligrams daily.

The study looked at 412 people, age 22 or older, randomly assigned to one of two dietary plans, each containing one of three levels of sodium: a high of 3,300 milligrams per day, an intermediate level of 2,400 milligrams and a low intake of 1,500 milligrams.

Members of each group consumed different levels of sodium at different stages of the trial, which lasted 14 weeks.

The two diets were a typical high-fat American diet with a lot of processed foods and snack foods and the so-called DASH (Dietary Approaches to Stop Hypertension) diet, which is low in saturated fats and cholesterol and high in fruits, vegetables, low-fat dairy products, whole grains, poultry, fish and nuts. It has little red meat, sweets and sugar.

The study showed that reducing salt resulted in lower blood pressure for all individuals and the lower the salt, the lower the readings.