Reducing salt consumption by just one teaspoon a day could lower your blood pressure as much as hypertension medication, according to research presented at the American Heart Association’s recent Scientific Sessions and published in JAMA.
The finding stems from a study of 213 adults, 50 to 75-years-old, including people whose blood pressure was considered normal, as well as those with high blood pressure (hypertension), either treated or untreated.
Researchers recorded the participants’ blood pressure after they had adhered, for one week, to a low-sodium diet – meals, snacks and beverages that included about one teaspoon less of table salt (2.3 grams of sodium) than their usual diet.
That was compared with the participants’ blood pressure after they had consumed a high-sodium diet for a week. For nearly three-fourths of the participants, blood pressure was lower with the low-sodium diet.
That diet resulted in, on average, a systolic blood pressure that was 8mmHg (millimetres of mercury, the standard of measurement for blood pressure) lower than the systolic pressure recorded after a high-sodium diet, and 6mmHg lower than after their usual diet.
Systolic blood pressure – the top (or first) number in a blood pressure reading – represents the force produced by the heart when it beats, pushing blood through the arteries.
Their findings indicate that “clinically meaningful lowering of (blood pressure) through dietary sodium reduction can be achieved safely and rapidly within one week”, said Deepak Gupta, MD, an associate professor of Medicine at Vanderbilt University Medical Centre and co-principal investigator.
Having high blood pressure increases a person’s risk for heart disease, heart attack or stroke but also raises the likelihood of developing a range of health problems, including kidney disease, visual problems, sexual dysfunction and peripheral artery disease, reports WebMD.
Nearly half of US adults – about 120m people – have hypertension or are taking medication for it, according to the Centres for Disease Control and Prevention.
Study details
Effect of Dietary Sodium on Blood Pressure: A Crossover Trial
Deepak Gupta, Cora Lewis, Krista Varady, et al.
Published in JAMA Network on 11 November 2023
Key Points
Question What is the impact of dietary sodium intake on blood pressure in middle-aged to elderly individuals?
Findings In this prospectively allocated diet order crossover study of 213 individuals, 1 week of a low-sodium diet resulted in an average 8–mm Hg reduction in systolic blood pressure vs a high-sodium diet, with few adverse events. The low-sodium diet lowered systolic blood pressure in nearly 75% of individuals compared with the high-sodium diet.
Meaning In this trial, the blood pressure–lowering effect of dietary sodium reduction was comparable with a commonly used first-line antihypertensive medication.
Abstract
Importance
Dietary sodium recommendations are debated partly due to variable blood pressure (BP) response to sodium intake. Furthermore, the BP effect of dietary sodium among individuals taking antihypertensive medications is understudied.
Objectives
To examine the distribution of within-individual BP response to dietary sodium, the difference in BP between individuals allocated to consume a high- or low-sodium diet first, and whether these varied according to baseline BP and antihypertensive medication use.
Design, Setting, and Participants
Prospectively allocated diet order with crossover in community-based participants enrolled between April 2021 and February 2023 in 2 US cities. A total of 213 individuals aged 50 to 75 years, including those with normotension (25%), controlled hypertension (20%), uncontrolled hypertension (31%), and untreated hypertension (25%), attended a baseline visit while consuming their usual diet, then completed 1-week high- and low-sodium diets.
Intervention
High-sodium (approximately 2200 mg sodium added daily to usual diet) and low-sodium (approximately 500 mg daily total) diets.
Main Outcomes and Measures
Average 24-hour ambulatory systolic and diastolic BP, mean arterial pressure, and pulse pressure.
Results
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.
Conclusions and Relevance
Dietary sodium reduction significantly lowered BP in the majority of middle-aged to elderly adults. The decline in BP from a high- to low-sodium diet was independent of hypertension status and antihypertensive medication use, was generally consistent across subgroups, and did not result in excess adverse events.
JAMA Network article – Effect of Dietary Sodium on Blood Pressure: A Crossover Trial (Open access)
WebMD article – Study: Cutting 1 Teaspoon of Salt As Good As Blood-Pressure Meds (Open access)
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