Drop that salt shaker to lower blood pressure

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A low-salt diet can lead to lower blood pressure for a majority of patients, whether they are using blood pressure medications or not.

A new study found middle-age to elderly patients who lowered their sodium intake, also lowered their systolic blood pressure by about the same amount as taking a first-line medication for high blood pressure. The decrease happened in a week.

“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,” co-principal investigator Deepak Gupta, MD, MSCO, said in a news release. Gupta is associate professor of medicine at Vanderbilt University Medical Center, which compiled the study with Northwestern Medicine and the University of Alabama at Birmingham.

In America, middle-aged and elderly adults consume an estimated 3.5 grams of sodium each day. That’s more than is recommended by the World Health Organization, U.S. Department of Health and Human Services, or the American Heart Association. Salt consumption contributes to high blood pressure, a leading cause of morbidity and mortality in the world, according to the researchers.

In the study, 213 patients, in their 50s to 70s, were divided into two groups, with one eating a low-salt diet, about 500 mg of sodium a day, and the other eating a high-salt diet, about 2,200 mg a day. The patients also had 24-hour ambulatory blood pressure monitoring and offered urine samples to assess dietary adherence. After a week, the groups traded diets.

Eating a low-salt diet, participants’ systolic blood pressure dropped 7 to 8 mm Hg compared to the high-salt diet, and by 6 mm Hg compared to the participants’ usual diet.

Overall, 72% of participants on the low-sodium diet lowered their systolic blood pressure, compared with their usual diets.

“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 the news release.

The researchers said the study was one of the largest to include participants with hypertension and already on blood pressure medications.

“We previously didn’t know if people already on blood pressure medication could actually lower their blood pressure more by reducing their sodium,” co-principal investigator Norrina Allen, PhD, MPH, said in the news release. Allen also is Quentin D. Young Professor of Health Policy, and director of the Center for Epidemiology and Population Health at Northwestern.

The study was published in the Journal of the American Medical Association and presented at the AHA Scientific Sessions 2023 in Philadelphia this month.

AHA recommends daily sodium intake stay below 1,500 mg. Allen noted the study participants had less than that.

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

The researchers noted there were “generally mild” adverse events for 21 participants, or 9.9%, on the high-sodium diet; those included headaches, gastrointestinal discomfort, and edema. On the low-sodium diet, 17 participants, or 8%, reported adverse effects such as cramping and weakness.