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• Posted November 13, 2023

Major Study Confirms Salt's Deadly Effect on Blood Pressure

Cutting out just one teaspoon of salt every day lowers blood pressure almost as much as medication does, new research shows.

Investigators said theirs is one of the largest studies ever to include people taking high blood pressure meds in a look at the effect of reducing dietary intake of sodium.

"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 study co-author Norrina Allen, a professor of preventive medicine at Northwestern University Feinberg School of Medicine in Chicago.

She said researchers previously didn't know if people already on blood pressure meds could lower their blood pressure even more by reducing their sodium intake.

In the study, middle-aged to elderly participants reduced their salt intake by about 1 teaspoon a day.

"The result was a decline in systolic blood pressure by about 6 millimeters of mercury (mm Hg), which is comparable to the effect produced by a commonly utilized first-line medication for high blood pressure,"said co-principal investigator Dr. Deepak Gupta, an associate professor of medicine at Vanderbilt University Medical Center, in Nashville, Tenn.

Systolic blood pressure is the pressure in your arteries as your heart beats. It's the first number in a blood pressure reading.

High blood pressure is a leading cause of illness and death worldwide. The added pressure on arteries can trigger heart failure, heart attacks and strokes. It affects the heart's ability to pump blood effectively, Allen said.

The study included 213 men and women, from 50-somethings to those in their 70s. They were randomly assigned to follow a high-sodium (2,200 milligrams (mg) per day on top of their usual diet) or a low-sodium diet (500 mg in total per day) for one week. Then, they switched and followed the other diet.

Before each study visit, participants wore blood pressure monitors and collected their urine for 24 hours.

Compared to their usual diet, 72% of participants had lower systolic blood pressure when they followed the low-sodium regimen.

Systolic pressure dropped 7 to 8 mm Hg when they ate the low-sodium diet compared to the high-sodium diet, and by 6 mm Hg compared with their usual eating habits, researchers said.

"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 Northwestern news release.

Researchers said the findings reinforce the importance of reducing sodium intake.

"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,"study co-author Dr. Cora Lewis, professor/chair of epidemiology at the University of Alabama at Birmingham, said in the release.

"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,"she added.

The findings were published Nov. 11 in the Journal of the American Medical Association and presented Saturday at an American Heart Association meeting in Philadelphia.

More information

Johns Hopkins Medicine has more about low-sodium diets and blood pressure.

SOURCE: Northwestern University, news release, Nov. 11, 2023