High-salt diets are commonly associated with increases in blood pressure and risk of cardiovascular mortality, even among individuals with healthy blood pressure.
Cardiologist Dr. Bradley Serwer, chief medical officer at cardiovascular and anesthesiology services provider VitalSolution, said: “For the general population, it is recommended to have a sodium intake of under 2300mg per day. For those with high blood pressure or heart disease, we recommend less than 1500mg per day. […]To put this in perspective, a tablespoon of salt has approximately 2,300mg of sodium.”
However, dietary sodium recommendations have been disputed, in part due to varying blood pressure responses to sodium consumption. The blood pressure effect of dietary sodium among people taking blood pressure medications has not been studied well to date, either.
A novel study sponsored by Vanderbilt University Medical Center found that a low sodium diet can reduce blood pressure as much as a prescription drug. These findings appear in JAMA Network.
Salt sensitivity of blood pressure (SSBP) refers to changes in blood pressure associated with changes in salt intake.
Blood pressure naturally fluctuates to maintain sodium balance. Susceptibility to SSBP may lie in sodium imbalances and abnormalities of hormones regulating sodium retention and excretion.
Vascular dysregulation may be responsible as well, but exactly how sodium influences blood pressure is yet to be understood.
Preliminary research suggests that excess dietary sodium consumption may cause inflammation, which can trigger high blood pressure.
The Coronary Artery Risk Development in Young Adults (CARDIA) study, which began in 1985, was chosen to explore the mechanisms behind SSBP. CARDIA utilized standardized low- and high-salt diets and 24-hour ambulatory blood pressure monitoring, which no other known U.S.-based inquiry had attempted.
The present study aimed “to examine the distribution of within-individual blood pressure response to dietary sodium, the difference in blood pressure between individuals allocated to consume a high- or low-sodium diet first, and whether these varied according to baseline blood pressure and antihypertensive medication use.”
The Coronary Artery Risk Development in Young Adults (CARDIA)–SSBP study recruited 213 community-based individuals between April 2021 and February 2023. The participants were 50 to 75 years of age.
Out of a total of 213 participants, 25% had typical blood pressure (normotension), 20% had controlled hypertension, 31% had uncontrolled hypertension, and 25% had untreated hypertension.
The participants were randomized into two groups. The groups either followed a high sodium diet, adding 2,200 mg to their usual diet for one week, or a low sodium diet, adding 500 mg of sodium for one week. Then, they switched diets for one week afterward.
The one-week low sodium diet resulted in a reduction in systolic blood pressure, mirroring the average effect of 12.5 mg of hydrochlorothiazide, a prescription hypertension drug.
Only 8% of the study participants reported any mild adverse events following this regimen, compared to 9.9% of those consuming the high sodium diet.
Moreover, the individual and between-group changes were not contingent on hypertension status or blood pressure medication use. The blood pressure declines were consistent across sub-groups as well.
Gupta DK, Lewis CE, Varady KA, et al. Effect of Dietary Sodium on Blood Pressure: A Crossover Trial. JAMA. Published online November 11, 2023. doi:10.1001/jama.2023.23651
Vanderbilt University Medical Center. 2023. Effect of Dietary Sodium on Blood Pressure. MedicalNewsToday. Retrieved November 15, 2023 from https://www.medicalnewstoday.com/articles/consuming-less-salt-blood-pressure-drugs