Shaking a Salt Habit
Easy does it!
A DASH of prevention continued...
One thing has long been certain: High blood pressure is dangerous. In findings published this year in The New England Journal of Medicine, for instance, scientists followed the fate of 12,000 men between the ages of 40 and 59. Those with sustained increases of 10 mmHg in systolic blood pressure and 5 mmHg in diastolic blood pressure were 28% more likely to die of heart disease than those with normal readings.
Given that danger, the new findings from the Dietary Approaches to Stop Hypertension (DASH) program are encouraging. Back in 1997, researchers from the DASH study showed that healthy volunteers who ate a diet rich in fruits and vegetables, with low- or nonfat dairy products and only modest amounts of meat, were able to lower their blood pressure by a couple of points. Those with hypertension saw the numbers fall by as much as 11 points.
The original DASH study didn't measure sodium intake, however. So a new one, called DASH-Sodium, was begun. Four hundred twelve adults were randomly assigned to follow one of two diets -- the typical American diet or the lower-fat DASH diet, which emphasizes fruits and vegetables, whole grains, poultry, fish, nuts, and low-fat dairy products. During the first four weeks, the volunteers in both groups consumed 3,300 milligrams of sodium a day -- about the average for most Americans. Over the next four weeks, they cut back to 2,400 milligrams a day. For the last four weeks -- no pretzels, no chips, no ifs, ands, or buts -- they consumed only 1,500 milligrams of sodium.
The results, reported in May at the American Society of Hypertension Meeting, were a slam-dunk. The less salt the volunteers ate, the further their blood pressures fell. The biggest benefit showed up in people with hypertension. On the DASH diet with only 1,500 milligrams of salt, systolic blood pressure fell 11.5 points. Surprisingly, even people with so-called normal blood pressure were able to lower their numbers by more than seven points.
"The study shows how important it is to reduce sodium in the diet," says Eva Obarzanek, MD, a nutrition expert at the National Heart Lung and Blood Institute (NHLBI), who helped direct the DASH-Sodium trial. Claude Lenfant, MD, the director of the NHLBI, went even further when announcing the results. "These finding show that an intake below that now recommended could help many Americans prevent the blood pressure rises that now occur with advancing age."