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Does cutting salt lower blood pressure?

Pooled data from 133 trials show cutting sodium lowers systolic blood pressure by about 4 mm Hg, and salt substitutes also cut strokes and deaths.

Published October 2026

Short answer

Yes - in randomised trials, cutting salt reliably lowers blood pressure, by about 4 mm Hg systolic on average and more when it starts higher. Salt substitutes do the same and, in a large Chinese trial, cut strokes and deaths. Evidence grade A (Strong). Consistent meta-analyses of more than 100 randomised trials measuring blood pressure directly; the salt-substitute outcome trials point the same way but are less certain and are reflected in the topic grades.

Key takeaways

  • In a meta-analysis of 133 randomised trials with 12,197 people, cutting sodium by about 130 mmol a day lowered systolic blood pressure by 4.26 mm Hg and diastolic by 2.07 mm Hg on average [1].
  • The fall was bigger in people who started with higher blood pressure - about 5.4/2.8 mm Hg with hypertension versus 2.4/1.0 mm Hg without in a Cochrane review [2].
  • The effect builds over weeks: trials shorter than 15 days showed roughly half the blood-pressure fall seen in longer trials [1].
  • Potassium-enriched salt substitutes lowered systolic pressure by about 4.6 to 4.8 mm Hg in reviews of 20-plus trials [3][4].
  • In a 20,995-person trial in rural China, replacing regular salt cut strokes by 14% and deaths by 12% over about five years; potassium-rich substitutes raise blood potassium, so kidney disease matters [5][3].

The short version

Yes - in randomised trials, cutting salt consistently lowers blood pressure, and the fall is larger when blood pressure starts higher [1][2]. Pooled across 133 trials, a substantial sodium cut lowered systolic blood pressure by 4.26 mm Hg and diastolic by 2.07 mm Hg on average [1]. Potassium-enriched salt substitutes do the same and, in the largest trial, also cut strokes and deaths in older adults at high risk [5].

What the studies show

The best single analysis comes from a 2020 review that pooled 133 randomised trials with 12,197 adults whose sodium intake was checked with 24-hour urine tests [1]. On average, people assigned to cut sodium excreted 130 mmol a day less, and their systolic blood pressure was 4.26 mm Hg lower (95% confidence interval 3.62 to 4.89) and diastolic 2.07 mm Hg lower (1.67 to 2.48) than people who kept their usual intake [1]. The bigger the sodium cut, the bigger the fall: each 50 mmol a day less was linked to about 1.1 mm Hg lower systolic pressure and 0.33 mm Hg lower diastolic pressure [1]. A 2021 analysis of 85 trials found an almost straight-line relationship between sodium intake and blood pressure across 0.4 to 7.6 g of sodium a day, with no sign that the benefit disappears at low intakes [6].

Older and newer reviews agree in the same range. A 2013 Cochrane review of 34 trials (3,230 people) found that a modest salt cut - about 4.4 g of salt a day for at least four weeks - lowered systolic pressure by 4.18 mm Hg and diastolic by 2.06 mm Hg [2]. A 2025 umbrella review of 21 meta-analyses put the average blood-pressure drop from low sodium intake at 3.39 mm Hg systolic and 1.54 mm Hg diastolic, and reported that each extra gram of sodium a day was linked to 0.60 mm Hg higher systolic pressure [7]. A network meta-analysis of 120 trials ranked salt restriction and low-sodium, high-potassium salt among the non-drug approaches that beat usual care for blood pressure [8].

How quickly does it work? The trials suggest the full effect takes several weeks to appear. In the 133-trial analysis, every 50 mmol a day sodium cut lowered systolic pressure by 2.13 mm Hg in studies lasting more than two weeks, but only 1.05 mm Hg in shorter studies [1]. In care-home residents followed for two years, blood pressure stayed lower in the salt-substitute group through to the end of the trial [9].

Salt substitutes - table salt with part of the sodium chloride replaced by potassium chloride - lower pressure through the same sodium cut [3]. A Cochrane review of 26 randomised trials (34,961 adults) found that people using substitutes had systolic pressure 4.76 mm Hg lower and diastolic 2.43 mm Hg lower than people using regular salt [3]. A separate meta-analysis of 21 trials (31,949 people) found similar falls of 4.61 and 1.61 mm Hg [4]. In a two-year trial in 48 Chinese care homes, residents using a substitute had 7.1 mm Hg lower systolic pressure than those using regular salt [9]. Among residents whose blood pressure was normal to start with, the substitute roughly halved new cases of hypertension (11.7 versus 24.3 cases per 100 person-years) without causing more episodes of low blood pressure [10].

Do the substitutes prevent heart attacks, strokes and deaths? The main evidence is the Salt Substitute and Stroke Study, a trial in 600 villages in rural China with 20,995 people who had had a stroke or were 60 or older with high blood pressure [5]. Over an average 4.74 years, those using a 75% sodium chloride, 25% potassium chloride substitute had 14% fewer strokes, 13% fewer major cardiovascular events and 12% fewer deaths than those using regular salt [5]. In the 15,249 participants with a previous stroke, recurrent strokes fell 14% and deaths 12% [11]. A 2024 meta-analysis of 16 trials lasting at least six months found salt substitution may reduce all-cause and cardiovascular deaths (rate ratios 0.88 and 0.83), but rated the certainty low: one large trial dominates the evidence and most participants came from China or Taiwan, so how well this applies to Western diets is uncertain [12].

There is a catch in the evidence. Cutting sodium itself - the kind of advice most people get - has much weaker proof that it prevents heart attacks and strokes, even though the blood-pressure effect is solid [13]. A 2014 Cochrane review of eight long trials found the data too limited to confirm a real effect on deaths or cardiovascular events, and its one positive pooled result for cardiovascular events came mostly from a single trial in retirement homes [13].

The nuances

The size of the benefit depends on where you start. The same sodium cut lowered pressure more in older people, in non-white populations and in people with higher starting blood pressure [1]. In the 2013 Cochrane review, people with hypertension saw average falls of 5.39/2.82 mm Hg, against 2.42/1.00 mm Hg in people with normal blood pressure [2]. People with normal pressure still gained in the care-home trial, where substitutes cut the rate of new hypertension roughly in half [10].

Most salt is already in food before it reaches the table. In a US study of 450 adults that collected duplicate samples of the salt they added, 70.9% of sodium came from food prepared outside the home, versus 5.6% from salt used in home cooking and 4.9% added at the table [14]. National survey data from 2009-2018 credited 62% of sodium to store-bought foods and 26% to restaurant-prepared foods [15]. So cutting table salt alone touches a small part of most diets [14].

Potassium is the trade-off in salt substitutes. Across six trials, blood potassium rose slightly - by about 0.12 mmol/L - with the substitutes [3]. The trials excluded people at higher risk of high blood potassium, such as people with chronic kidney disease or those taking medicines that reduce potassium excretion, so safety in those groups is not established [3]. A modelling study of nationwide salt substitution in China estimated about 450,000 fewer cardiovascular deaths a year, alongside roughly 11,000 extra deaths from high potassium in people with chronic kidney disease - a net benefit, but a real trade-off [16].

In chronic kidney disease itself, a Cochrane review of 21 small trials (1,197 people) found salt reduction lowered blood pressure by about 6.9/3.9 mm Hg, but also that lower-salt diets may lead to symptomatic low blood pressure (risk ratio 6.70) [17]. And no studies have tested salt substitutes in pregnant women, with effects in children very uncertain [3].

What this means for you

The blood-pressure effect of cutting salt is one of the more reliable findings in nutrition - and it is bigger for people whose pressure is already high [1][2]. Because most sodium sits in food prepared outside the home, the salt shaker is a small lever; the trials that showed fewer strokes and deaths swapped regular salt for a potassium-enriched substitute used at home [14][5]. Those substitutes were about 62% to 75% sodium chloride with 25% potassium chloride [5][9]. If you have chronic kidney disease, or you take medicines that affect potassium levels, the potassium in salt substitutes matters - the trials that showed benefit left those people out, so it is worth checking with a doctor or pharmacist first [3][17].

Go deeper

  • Salt — Cutting salt lowers blood pressure - by about 4 mm Hg systolic in pooled trials, and more when blood pressure starts higher.

References

  1. Effect of dose and duration of reduction in dietary sodium on blood pressure levels: systematic review and meta-analysis of randomised trials.. BMJ, 2020.
  2. Effect of longer-term modest salt reduction on blood pressure.. Cochrane Database Syst Rev, 2013.
  3. Replacing salt with low-sodium salt substitutes (LSSS) for cardiovascular health in adults, children and pregnant women.. Cochrane Database Syst Rev, 2022.
  4. Effects of salt substitutes on clinical outcomes: a systematic review and meta-analysis.. Heart, 2022.
  5. Effect of Salt Substitution on Cardiovascular Events and Death.. N Engl J Med, 2021.
  6. Blood Pressure Effects of Sodium Reduction: Dose-Response Meta-Analysis of Experimental Studies.. Circulation, 2021.
  7. Dietary salt intake and cardiovascular outcomes: an umbrella review of meta-analyses and dose-response evidence.. Ann Med, 2025.
  8. Nonpharmacologic Interventions for Reducing Blood Pressure in Adults With Prehypertension to Established Hypertension.. J Am Heart Assoc, 2020.
  9. Salt substitution and salt-supply restriction for lowering blood pressure in elderly care facilities: a cluster-randomized trial.. Nat Med, 2023.
  10. Effect of a Salt Substitute on Incidence of Hypertension and Hypotension Among Normotensive Adults.. J Am Coll Cardiol, 2024.
  11. Salt Substitution and Recurrent Stroke and Death: A Randomized Clinical Trial.. JAMA Cardiol, 2025.
  12. Long-Term Effect of Salt Substitution for Cardiovascular Outcomes : A Systematic Review and Meta-analysis.. Ann Intern Med, 2024.
  13. Reduced dietary salt for the prevention of cardiovascular disease.. Cochrane Database Syst Rev, 2014.
  14. Sources of Sodium in US Adults From 3 Geographic Regions.. Circulation, 2017.
  15. Sodium Content and Sodium Intake Contributions of Store-Bought and Restaurant-Prepared Foods in Their As-Eaten Form: National Health and Nutrition Examination Survey, 2009-2018.. Curr Dev Nutr, 2024.
  16. Estimated population wide benefits and risks in China of lowering sodium through potassium enriched salt substitution: modelling study.. BMJ, 2020.
  17. Altered dietary salt intake for people with chronic kidney disease.. Cochrane Database Syst Rev, 2021.