According to a new study from Northwestern Medicine, Vanderbilt University Medical Center, and the University of Alabama at Birmingham, nearly everyone, including people on blood pressure medications, can lower their blood pressure by lowering their sodium intake.
“Middle-aged to elderly participants in the study reduced their salt intake by about 1 teaspoon per day compared to their usual diet. The result was a drop in systolic blood pressure of about 6 millimeters of mercury (mm Hg), which is comparable to the effect produced by a commonly used first-line medication for high blood pressure,” said Dr. Deepak Gupta, associate professor of medicine and co-principal investigator at Vanderbilt University Medical Center.
“We found that 70-75% 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, professor of preventive medicine at Northwestern University Feinberg School of Medicine.
This is one of the largest studies to look into the effect of lowering sodium in the diet on blood pressure in people who have hypertension and are already taking medications.
High blood pressure can lead to heart failure, heart attacks, and strokes because it puts extra pressure on your arteries. It affects the heart’s ability to work effectively and pump blood.
Norrina Allen
“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 the Quentin D. Young Professor of Health Policy and director of the Center for Epidemiology and Population Health.
The findings of the study will be published in the Journal of the American Medical Association and presented at the American Heart Association Scientific Sessions in Philadelphia in 2023. The AHA recommends a total daily sodium intake of less than 1,500 milligrams, and this study was designed to reduce it even further, according to Allen. “It can be challenging but reducing your sodium in any amount will be beneficial,” she went on to say.
High blood pressure is the world’s leading cause of morbidity and mortality. “High blood pressure can lead to heart failure, heart attacks, and strokes because it puts extra pressure on your arteries,” he 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, Alabama, and Chicago were randomized to either a high-sodium diet (2,200 mg per day on top of their usual diet) or a 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 the high-sodium diet, and by 6 mm Hg compared with their usual diet. Overall, 72% 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 in a press release.
“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,” he went on to say. “This reinforces the importance of reduction in dietary sodium intake to help control blood pressure, even among individuals taking medications for hypertension,” he said.
Within one week, the blood pressure-lowering effect of dietary sodium reduction was achieved quickly and safely.
“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-author Dr. Cora Lewis, 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,” said Lewis.
