Saturday Sep 20, 2008 (foodconsumer.org) -- A new Italian study shows that about half overweight people with stage 1 hypertension or high blood pressure can get their blood pressure normalized by simply losing 5 to 12 percent weight and normalizing their body mass index.

The study was conducted by Roberto Fogari and colleagues at Universita` di Pavia in Pavia, Italy and presented at the 62nd High Blood Pressure Research Conference 2008 in Atlanta, GA.

The study was meant to evaluate the role of weight loss on blood pressure values in overweight people with stage 1 hypertension who never received any medications to treat their hypertensive condition.

The study involved 189 overweight people (BMI 25 to 29.9 kg/m2) with stage 1 hypertensive outpatients (systolic blood pressure or SBP=140-159 mmHg and diastolic blood pressure or DBP 90 - 99mmHg). The participants were given dietary advice and or 120 to 360 mg of Orlistat per day to achieve a 5-percent-loss in the body weight in 6 months.

Those who successfully lost the targeted 5 percent body weight continued the treatment for another 6 months and blood pressure and body weight were measured every month.   At baseline, 6 and 12 months of the treatment, 24-hour ambulatory blood pressure was evaluated and blood samples were drawn to test plasma leptin, active renin and aldosterone.

The researchers found 111 participants or 59 percent of the study subjects achieved 5 percent reduction in their body weight.

It's found that those who lost the targeted amount of body weight experienced a significant drop in SBP and DBP (-6.9 and -4.2 percent respectively) and high weight loss resulted in high reduction in blood pressure.

In addition, those who lost 5 percent of the body weight also experienced a reduction in plasma leptin, active renin and aldosterone.

Among those who achieved 5 percent loss in the body weight, fifty three or 48 percent normalized their BMI and 28 of them or 53 percent normalized their blood pressure. The levels of leptin, renin and aldosterone in the 28 people who normalized their blood pressure are not different from those of the remaining 25.

Another study presented also at the American Heart Association's Fall Conference of the Council for High Blood Pressure Research, in Atlanta shows too much dietary salt can contribute to resistant high blood pressure.

Resistant hypertension refers to a condition where blood pressure remains above the target level even when three medications are used in an effort to lower it.   High blood pressure is also called resistant to treatment if the condition can only get controlled by taking four or more medications.

The study led by the University of Alabama researchers involved 13 patients with resistant high blood pressure. Participants were assigned to a high or low salt diet and all of them were taking at least three blood pressure medications.

The researchers found those assigned the low-salt diet reduced their systolic blood pressure by 22.6 percent and diastolic blood pressure by 9.2 percent compared to those who were assigned to the high-salt diet.

A Japanese study also presented at the conference showed that high salt diet can exacerbate hypertension via an increase in oxidative stress.

"Excess sodium intake, above 2,300 milligrams daily, should be avoided in all patients with hypertension, and among those patients with medically resistant hypertension, a closely monitored low-salt diet [1,500 milligrams daily] should be considered," Dr. Gregg C. Fonarow, a professor of cardiology at the University of California, Los Angeles was quoted by healthday.com as saying.