Cut Salt, Cut Blood Pressure

Nearly everyone can lower their blood pressure, even people currently on blood pressure-reducing drugs, by lowering their sodium intake, reports a new study published in JAMA from Northwestern Medicine, Vanderbilt University Medical Center and the University of Alabama at Birmingham. 

“In the study, middle-aged to elderly participants reduced their salt intake by about one teaspoon a day compared with their usual diet. The result was a decline in systolic blood pressure by about six millimeters of mercury (mm Hg), which is comparable to the effect produced by a commonly utilized first-line medication for high blood pressure,” said Deepak Gupta, MD, associate professor of medicine at Vanderbilt University Medical Center and co-principal investigator.

“We found that 70-75 percent of all people, regardless of whether they are already on blood pressure medications or not, are likely to see a reduction in their blood pressure if they lower the sodium in their diet,” said co-principal investigator Norrina Allen, PhD, the Quentin D. Young Professor of Health Policy in the Department of Preventive Medicine and co-principal investigator of the study.

This is one of the largest studies to investigate the effect of reducing sodium in the diet on blood pressure that includes people with hypertension and already on medications.

“We previously didn’t know if people already on blood pressure medication could actually lower their blood pressure more by reducing their sodium,” said Allen, also a professor of Pediatrics and director of the Center for Epidemiology and Population Health in the Institute for Public Health and Medicine.

The study was presented this week at the American Heart Association Scientific Sessions 2023 in Philadelphia.

The total daily sodium intake recommended by the AHA is to be below 1,500 milligrams, and this study was designed to decrease it even lower than that, Allen said.

“It can be challenging but reducing your sodium in any amount will be beneficial,” she said.

High blood pressure is the leading cause of morbidity and mortality in the world.

“High blood pressure can lead to heart failure, heart attacks and strokes, because it puts extra pressure on your arteries,” Allen said. “It affects the heart’s ability to work effectively and pump blood.”

How the study worked

Middle-aged to elderly individuals in their 50s to 70s from Birmingham, Ala., and Chicago were randomized to either a high-sodium diet (2,200 mg per day on top of their usual diet) or low-sodium diet (500 mg in total per day) for one week, after which they crossed over to the opposite diet for one week.

On the day before each study visit, participants wore blood pressure monitors and collected their urine for 24 hours. Among 213 participants, systolic blood pressure was significantly lowered by 7 to 8 mm Hg when they ate the low-sodium diet compared with high-sodium diet, and by 6 mm Hg compared with their usual diet. 

Overall, 72 percent of participants experienced a lowering of their systolic blood pressure on the low-sodium diet compared with their usual diet. 

“The effect of reduction in dietary sodium on blood pressure lowering was consistent across nearly all individuals, including those with normal blood pressure, high blood pressure, treated blood pressure and untreated blood pressure,” Gupta said.

“Just as any physical activity is better than none for most people, any sodium reduction from the current usual diet is likely better than none for most people with regards to blood pressure,” Gupta said.

“This reinforces the importance of reduction in dietary sodium intake to help control blood pressure even among individuals taking medications for hypertension,” Allen added.

The blood pressure lowering effect of dietary sodium reduction was achieved rapidly and safely within one week.

“The fact that blood pressure dropped so significantly in just one week and was well tolerated is important and emphasizes the potential public health impact of dietary sodium reduction in the population, given that high blood pressure is such a huge health issue worldwide,” said co-investigator Cora Lewis, MD, professor and chair of the Department of Epidemiology and professor of Medicine at the University of Alabama at Birmingham.

“It is particularly exciting that the products we used in the low-sodium diet are generally available, so people have a real shot at improving their health by modifying their diet in this way,” Lewis said.

Source: https://news.feinberg.northwestern.edu/2023/11/13/cut-salt-cut-blood-pressure/

Journal article: https://jamanetwork.com/journals/jama/fullarticle/2811931 

Source: Cut Salt, Cut Blood Pressure – Scents of Science (myfusimotors.com)