Thu, Sep 24, 2009 - Page 14 News List

[ HEALTH ] Too much salt takes a high toll on blood pressure

Sedentary lifestyles, expanding waistlines and high salt intake increase risk of hypertension

By Jane E. Brody  /  NY TIMES NEWS SERVICE , NEW YORK

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Perhaps nothing in medicine more aptly depicts the paradoxical statement “doing better, feeling worse” than high blood pressure. Despite an extraordinarily easy way to detect it, strong evidence for how to prevent it and proven remedies to treat it, more Americans today have undetected or poorly controlled hypertension than ever before.

The aging of the population is a reason but not the only one, said Aram Chobanian, a hypertension expert at Boston University Medical Center. As he summarized the problem in an interview and in The New England Journal of Medicine last month, Americans are too sedentary and fat. They eat too much, especially salt, but too few potassium-rich fruits and vegetables.

The makers of processed and fast foods created and persistently promote a craving for high-salt foods, even in school lunch programs. And Americans without health insurance often don’t know that their blood pressure is too high because they wait for a calamity to strike before seeking medical care.

Solutions to the blood pressure problem require broad-scale approaches — by the public, by government, by industry and by health care professionals. Several measures are similar to those that have been so effective in curbing cigarette smoking; others require better, affordable access to medical care for everyone at risk, including children and the unemployed. Still others need the cooperation of government, industry and the public to improve the American diet and enhance opportunities for health-promoting exercise.

No one claims that the solutions are cheap. But failure to fix this problem portends even greater costs down the line, because uncontrolled hypertension sets the stage for astronomically expensive heart and kidney disease and stroke — diseases that will become only more common as the population ages.

DOING THE NUMBERS

Once, the prevailing medical opinion was that lowering an elevated blood pressure was hazardous because it would deprive a person’s vital organs of an adequate blood supply. But a few pioneering medical researchers thought otherwise and eventually showed that lowering high blood pressure could prevent heart attacks, heart failure, strokes and kidney disease — and save lives.

Even then, it was long thought that the only important indicator was diastolic pressure — the bottom number, representing the pressure in arteries between heartbeats. Further studies showed that the larger top number, systolic pressure, representing arterial pressure when the heart beats, was also medically important.

And as the various studies reached fruition, it became apparent that the long-accepted numbers for desirable blood pressure were too high to protect long-term health.

Now the upper limit of normal blood pressure is listed as 120 over 80; anyone with a pressure of 140 over 90 or higher is considered hypertensive. Those with pressures in between are considered pre-hypertensive and should take steps to bring blood pressure down or, at least, prevent it from rising more.

The change mirrors what happened with serum cholesterol, for which “normal” was once listed as 240 milligrams per deciliter of blood and is now less than 200 to prevent heart disease caused by clogged arteries.

It was also long thought that blood pressure naturally rises with age. Indeed, the Framingham Heart Study showed that when 65-year-old people whose blood pressure was below 140 over 90 were followed for 20 years, about 90 percent of them became hypertensive because their arteries narrowed and stiffened with age, causing blood to push harder against artery walls.

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