Reducing salt intake can reduce blood pressure, study finds

The study found that 70-75 percent of all participants, regardless of whether they were already on blood pressure medications or not, were likely to see a reduction in their blood pressure if they lowered the sodium in their diet.Hypertension, or high blood pressure, is the leading underlying cause of death worldwide affecting more than 1.25 billion people, including more than 100 million Americans. Most people worldwide eat more salt than recommended.

So, is there a connection?

Nearly everyone can lower their blood pressure, even people currently on blood pressure reducing drugs, by lowering their sodium intake, reports a new study from the University of Alabama at Birmingham, Vanderbilt University Medical Center and Northwestern Medicine. Results were published in the Journal of the American Medical Association and presented at the American Heart Association Scientific Sessions 2023 on Nov. 11.  

“A number of studies link high salt intake to high blood pressure and a higher risk of premature death and cardiovascular disease, including heart attacks and strokes,” said Cora Lewis, M.D., professor in UAB’s School of Public Health and co-investigator of the study. “From previous trials, we know that a lower-sodium diet lowers blood pressure on average, but, for reasons not yet clear, some people are more salt-sensitive than others.”

The trial was an ancillary study to the UAB Coronary Artery Risk Development in Young Adults, or CARDIA, study, co-led by Lewis. Middle-aged to older individuals in their 50s to 70s were placed on a high-sodium diet (2,200 milligrams per day on top of their normal diet) and a low-sodium diet (500 mg total in a day), each for one week at a time.  

The study found that 70-75 percent of all participants, regardless of whether they were already on blood pressure medications or not, were likely to see a reduction in their blood pressure if they lowered the sodium in their diet. Overall, 72 percent of participants experienced a lowering of their systolic blood pressure on the low-sodium diet compared with their usual diet. 

“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,” said Deepak Gupta, M.D., associate professor of Medicine at Vanderbilt University Medical Center and co-principal investigator.

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

“The results reinforce the importance of reduction in dietary sodium intake to help control blood pressure, even among individuals taking medications for hypertension,” said co-principal investigator Norrina Allen, Ph.D., professor of preventive medicine at Northwestern University Feinberg School of Medicine. “It can be challenging but reducing your sodium in any amount will be beneficial.”

The study is one of the largest to investigate the effect of reducing sodium in the diet on blood pressure to include people with hypertension who are already on medications. Lewis says the rapid, safe and significant reduction in blood pressure by reducing dietary sodium intake in one week shows the potential public health impact of the results.

“Given that high blood pressure is a huge health issue worldwide, the results provide a promising and accessible way to reduce hypertension caused by sodium intake,” Lewis said. “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 through improving their diet in this way.”

The research was supported by grant R01HL148661 and contracts 75N92023D00005 and 75N92023D00004 from the National Heart Lung and Blood Institute of the National Institutes of Health. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health