A clue to why less salt is better

Six years ago, the DASH diet, or Dietary Approaches to Stop Hypertension, which is rich in fruits, vegetables and low-fat dairy foods, proved effective in lowering blood pressure -- and physicians have been recommending it ever since. But only now have researchers found out why it works.

The diet appears to act as a natural diuretic, eliminating sodium and water from the bloodstream, just as a water pill or diuretic drug does. With less water and sodium surging through the blood vessels, pressure decreases.

Nearly 400 adults with high blood pressures ranging from 130 to 159 systolic and 85 to 99 diastolic followed the DASH diet or a control diet for 120 days, varying their salt intake slightly every month.

After 30 days, an analysis of the participants’ blood pressure and the amount of salt in their urine showed that those on the DASH diet had excreted larger amounts of salt and had lowered their blood pressure more than those on the control diet.

The lowest average blood pressure was achieved by DASH followers who used the least amount of salt. Those who consumed the lowest amount of salt in the control group also had a decrease in blood pressure, but according to American Heart Assn. spokesperson Njeri Karanja, “DASH gets there faster.”

“We don’t know if following the DASH diet will actually prevent high blood pressure, because the studies haven’t been done yet,” she says.

But, she adds, it’s a healthful diet that everyone with hypertension or a family history of the condition should try.

The study was published in July issue of the journal Hypertension. For more on the diet, go to www.nhlbi.nih.gov/health/public/heart/hbp/dash.