A study shows that lowering dietary sodium reduces blood pressure (BP) in most middle-aged to older adults, regardless of hypertension status and antihypertensive medication use. “In this trial, the blood pressure–lowering effect of dietary sodium reduction was comparable with a commonly used first-line antihypertensive medication,” the authors conclude.
In a pair of U.S. cities from Apr. 2021 to Feb. 2023, individuals aged 50 to 75 years (n = 213) had normotension (25%), controlled hypertension (20%), uncontrolled hypertension (31%), and untreated hypertension (25%). For 1 week, they consumed high-sodium (approximately 2200 mg sodium added daily to the usual diet) and low-sodium (approximately 500 mg daily total) diets.
Based on the average 24-hour ambulatory systolic and diastolic BP, mean arterial pressure, and pulse pressure, the investigators found: “Among the 213 participants who completed both high- and low-sodium diet visits, the median age was 61 years, 65% were female and 64% were Black. While consuming usual, high-sodium, and low-sodium diets, participants’ median systolic BP measures were 125, 126, and 119 mm Hg, respectively. The median within-individual change in mean arterial pressure between high- and low-sodium diets was 4 mm Hg (IQR, 0-8 mm Hg; P < .001), which did not significantly differ by hypertension status. Compared with the high-sodium diet, the low-sodium diet induced a decline in mean arterial pressure in 73.4% of individuals. The commonly used threshold of a 5 mm Hg or greater decline in mean arterial pressure between a high-sodium and a low-sodium diet classified 46% of individuals as ‘salt sensitive.’ At the end of the first dietary intervention week, the mean systolic BP difference between individuals allocated to a high-sodium vs a low-sodium diet was 8 mm Hg (95% CI, 4-11 mm Hg; P < .001), which was mostly similar across subgroups of age, sex, race, hypertension, baseline BP, diabetes, and body mass index. Adverse events were mild, reported by 9.9% and 8.0% of individuals while consuming the high- and low-sodium diets, respectively.”