Reducing blood pressure is one of the top ways to reduce the risk of future heart attack and stroke. New research from Northwestern Medicine, Vanderbilt University Medical Center and the University of Alabama at Birmingham finds that reducing salt intake can drop blood pressure even among those taking medication for hypertension.

According to Dr. Deepak Gupta, associate professor of medicine at Vanderbilt University Medical Center and co-principal investigator, "Middle-aged to elderly participants reduced their salt intake by about 1 teaspoon a day compared with their usual diet. 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."

Co-principal investigator Norrina Allen, professor of preventive medicine at Northwestern University Feinberg School of Medicine, noted that in 70–75% of people, cutting back on sodium in their diet reduced blood pressure whether they were already on medications for blood pressure or not.

According to Allen, who is also the Quentin D. Young Professor of Health Policy and director of the Center for Epidemiology and Population Health, "We previously didn't know if people already on blood pressure medication could actually lower their blood pressure more by reducing their sodium.”

The study presented at the American Heart Association Scientific Sessions 2023 in Philadelphia was published Nov. 11 in the Journal of the American Medical Association.

The American Heart Association advised 1500 mg of sodium or less per day for this study, though according to Allen, the study suggested an even lower amount. She notes, "It can be challenging but reducing your sodium in any amount will be beneficial."

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."

The Study Design

Allen’s study included adults in their 50s to 70s from Birmingham and Chicago. Subjects were randomized to eat a high sodium diet (2200 mg per day above their usual diet) or a low-sodium diet (500 mg total daily) for one week. They then crossed over to the other diet for a week.

Participants wore blood pressure monitors on the day before each study visit and collected their urine for 24 hours. Among the 213 subjects, systolic blood pressure was significantly reduced by 7 to 8 mm Hg when they consumed the low-sodium diet compared to the high-sodium diet, and lower by 6 mm Hg compared to their typical diet.

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.

Compared with their typical diet, 72% of subjects had a lower systolic blood pressure with the low-sodium 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.

He also notes, “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.”

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

The impact on blood pressure within a week using a low-sodium diet was reached 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-investigator Dr. Cora Lewis, professor and chair of the department of epidemiology and professor of medicine at the University of Alabama at Birmingham.

Lewis also notes, "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."

The research was supported by a grant and contracts from the National Heart, Lung and Blood Institute of the National Institutes of Health.

Below are tips to give your clients to help reduce their sodium intake.

1. Read labels for sodium content. Anything below 140 mg per serving is considered low in sodium. Avoid foods with 15% or more of the Daily Value for sodium.

2. Limit intake of fast food, frozen meals, and salty snacks. Boxed pasta and rice mixes also tend to be high in sodium.

3. Taste food first before adding salt.

4. Use flavored powders in place of salts such as garlic powder, onion powder, or celery powder.

5. Go for low-sodium versions of ketchup, soy sauce, BBQ sauce and other condiments.

6. Try citrus juice or flavored vinegar to season vegetables or meats in place of salty sauces or marinades.

7. Make your own salad dressing with lemon or lime juice, vinegar, dried or fresh herbs, and healthy oils like avocado, canola, or olive.

8. Top dishes with fresh herbs including basil, cilantro or mint.

9. Season vegetables or proteins with garlic, onions, mushrooms, or peppers.

10. Use spices in place of salt on beef, eggs, fish, pork, or poultry.

Lisa Andrews, MEd, RD, LD

Reference:

1. Deepak K. Gupta, Cora E. Lewis, Krista A. Varady, Yan Ru Su, Meena S. Madhur, Daniel T. Lackland, Jared P. Reis, Thomas J. Wang, Donald M. Lloyd-Jones, Norrina B. Allen. Effect of Dietary Sodium on Blood Pressure. JAMA, 2023; DOI: 10.1001/jama.2023.23651