Cut Hypertension Drugs With Low-Salt Diet
 

Reported July 20, 2009

July 20, 2009 -- Lowering daily salt intake may reduce the need to prescribe additional medications to control high blood pressure, according to a new study.

Patients with resistant hypertension are those who take three or more medicines to try and control their blood pressure, but their readings are still high. "These patients especially benefit from a low-salt diet," says study lead author Eduardo Pimenta, MD, a clinical research fellow in the hypertension department of the University of Queensland in Brisbane, Australia.

"Doctors tend to add more and more antihypertensive medications," he says, but ''these patients could have their blood pressure controlled with a low-salt diet and fewer medications." Based on his study, he says, doctors should consider additional lifestyle intervention, reinforcing to patients the importance of a low-salt diet before adding more drugs.

The study is published in Hypertension: Journal of the American Heart Association. In the same issue, another study found that modest salt reduction reduced blood pressure in blacks, whites, and Asians who had mildly elevated pressures, and that the low-salt diet also produced other health benefits.

While many studies have found a link between dietary sodium and blood pressure, exactly how dietary sodium affects the resistant form of high blood pressure isn't well-known, according to Pimenta.

In his study, he assigned 12 men and women, average age 55, all with high blood pressure even while taking an average of 3.4 medicines, to eat a high-salt diet for one week and a low-salt diet for one week, separating the two diet experiments by a two-week "washout" period.

The average body mass index (BMI) was nearly 33, considered obese. At the study start, the average blood pressure while taking the medications was about 146/84. (Ideal blood pressures are below 120/80. If pressures are repeatedly over 140/90, it is considered hypertension.)

When the participants were on the high-salt diet, they took in about 7,000 milligrams of sodium per day, according to Pimenta; while on the low-salt diet they took in about 2,000 to 3,000 milligrams of sodium. Under U.S. dietary guidelines, less than 2,300 milligrams of sodium a day, or about one teaspoon of salt, is recommended for the general population; 1,500 milligrams is recommended for those with high blood pressure. The average American gets 3,436 milligrams of sodium a day, according to the American Heart Association.
Salt and Resistant Blood Pressure Study: Results

Compared to the high-salt diet, after being on the low-salt diet for a week, the participants had an average drop of 22.7 points for systolic blood pressure (the top number) and 9.1 for diastolic blood pressure (the bottom number).

The drop, Pimenta writes, is larger than what has been found in other blood pressure studies, suggesting that those with resistant hypertension may be especially sensitive to high salt intake.

"Doctors should reinforce the importance of a low-salt diet," Pimenta tells WebMD. "I think they should refer these patients to a nutritionist."