Does cutting salt lower blood pressure?

Yes. A Cochrane meta-analysis of 34 randomized trials in 3230 people found that eating about 4.4 g less salt a day for at least four weeks lowered systolic blood pressure by 4.18 mm Hg (95% CI 3.18 to 5.18). The fall was 5.39 mm Hg in people with high blood pressure and 2.42 mm Hg in people with normal pressure. The less salt, the lower the pressure, and the trials found no level where the pressure stops falling.

Established. Cutting salt lowers blood pressure. Several meta-analyses of randomized trials agree on the direction, and the size depends on who you are. People who already have high blood pressure, older people and non-white groups see larger falls for the same cut.

What the trials found

The more you cut, the more it drops

The largest dose analysis pooled 133 randomized studies in 12,197 adults whose intake was measured in 24 hour urine. Each 50 mmol less sodium a day, about 1.15 g, lowered systolic pressure by 1.10 mm Hg (0.66 to 1.54). The same cut did more in older people, in non-white populations and in people who started with higher pressure.

A second dose analysis of 85 trials lasting four weeks or more found the curve was almost a straight line, with no flattening even at the lowest intakes. Across the whole range of sodium the trials covered, the modeled difference came to more than 15 mm Hg systolic and nearly 10 mm Hg diastolic. That is a modeled curve over very different intakes, mostly in people with hypertension, and most of the trials did not describe how they randomized.

Short trials undercount it

In trials shorter than 15 days, each 50 mmol cut lowered systolic pressure by 1.05 mm Hg. In longer trials the same cut lowered it by 2.13 mm Hg. A week of eating less salt shows only part of what months of it would do.

It works on top of medicine

Across 35 randomized trials in 2885 people whose blood pressure drugs stayed the same, each 100 mmol less sodium a day, about 2.3 g, lowered systolic pressure by a further 6.81 mm Hg (4.96 to 8.66). The trials were short, with a median of 28 days, and the effect differed by drug class. A separate US study of 213 adults aged 50 to 75 found one week of a very low sodium diet lowered blood pressure in 73.4 percent of them against a high sodium week, whether or not they took blood pressure drugs. Its diet order was assigned in advance but not described as randomized, so it counts as weaker evidence.

Normal blood pressure: smaller, and here the reviews disagree

A Cochrane review that also counted very short trials compared low with high sodium diets. In white adults with hypertension, systolic pressure fell 5.71 mm Hg. In white adults with normal pressure it fell 1.14 mm Hg (0.63 to 1.65), and diastolic pressure did not move.

Unsettled. Whether cutting salt is worth it for people whose pressure is already normal is still argued over. The benefit in them is small on every review. The Cochrane authors behind the 1.14 mm Hg figure also report hormone and lipid changes that they count as possible side effects, and the reviews that keep only trials of four weeks or more do not see the lipid change. The disagreement is mostly about which trials to count.

Salt substitutes, and a trial with strokes as the outcome

Swapping table salt for a potassium based lower sodium substitute lowered systolic pressure by 4.76 mm Hg (3.50 to 6.01) across 20 trials in 21,414 adults, on moderate certainty evidence. One large trial went further and counted events. In 20,995 people in rural China with a past stroke, or aged 60 and over with high blood pressure, a substitute that was 25 percent potassium chloride was used for 4.74 years. Strokes fell to 29.14 per 1000 person-years against 33.65 on regular salt, a rate ratio of 0.86 (0.77 to 0.96). The trial was open label and its people ate a lot of salt to begin with.

Children

In 18 experimental and observational studies of 3406 children and adolescents, each extra gram of sodium a day went with 0.8 mm Hg higher systolic pressure (0.4 to 1.3). That mixes study types and shows an association. The US AHRQ review judged that cutting sodium may not lower systolic pressure in children, on low strength evidence. The evidence in children is less settled than in adults.

Who should be careful

Cutting salt shifts some hormones. In trials of four weeks or more, renin, aldosterone and noradrenaline rose a little and cholesterol and triglycerides did not change significantly. The Cochrane review that pooled shorter trials too found total cholesterol up 5.19 mg/dL (2.1 to 8.3) and triglycerides up 7.10 mg/dL (3.1 to 11.1). Nobody knows yet what the rise in renin and aldosterone means for health over years.

Not for everyone. Potassium salt substitutes are where the real caution sits. They probably raise blood potassium slightly, by 0.12 mmol/L (0.07 to 0.18). Every trial in the Cochrane review left out people for whom extra potassium is known to be harmful, and none studied pregnant women. The WHO recommendation to use them excludes people with kidney impairment, people taking potassium-sparing diuretics or potassium supplements, anyone else whose body may not clear potassium well, children and pregnant women. If you are in one of those groups, ask whoever treats you before you switch.

What expert bodies say

WHO strongly recommends that adults eat less than 2 g of sodium a day, which is 5 g of salt, and strongly recommends cutting sodium to control blood pressure in children, with limits scaled down to their energy needs. A 2025 WHO guideline adds a conditional suggestion that adults in the general population swap regular salt for potassium-containing lower sodium substitutes, with the exclusions above. The US AHRQ evidence review found the evidence insufficient to say whether race changes the effect, and judged on low strength evidence that cutting sodium may not lower systolic pressure in children.

How we searched

What would change this answer

• Trials of salt substitutes in pregnant women and in people at risk of high potassium. The Cochrane review found none, and those are exactly the people the advice now leaves out.
• Longer trials in people with normal blood pressure that report hormones and lipids at six months or more. That would settle whether the lipid rise seen in short trials is real or passing.
• Better trials in children. The pooled association and the AHRQ verdict point in different directions.
• Two 2026 analyses, one on who is salt sensitive and one comparing salt substitutes, which we found but did not turn into cards here. One registered salt substitute trial has an unknown status.

How much sodium is in common foods, and where it hides, is on the salt page.

Sources

1. ev-sodbp-01 · Meta-analysis or systematic review · Cochrane systematic review and meta-analysis of RCTs · n = 3230
   Thirty four trials (3230 participants) were included. Meta-analysis showed that the mean change in urinary sodium (reduced salt v usual salt) was -75 mmol/24 h (equivalent to a reduction of 4.4 g/day salt), and with this reduction in salt intake, the mean change in blood pressure was -4.18 mm Hg (95% confidence interval -5.18 to -3.18, I(2)=75%) for systolic blood pressure and -2.06 mm Hg (-2.67 to -1.45, I(2)=68%) for diastolic blood pressure.
   
   Who: randomized trials of modest salt reduction lasting at least four weeks, hypertensive and normotensive adults
   Effect: SBP -4.18 mm Hg (95% CI -5.18 to -3.18), DBP -2.06 mm Hg (-2.67 to -1.45) for -75 mmol/24 h urinary sodium; hypertensive SBP -5.39 (-6.62 to -4.15), normotensive SBP -2.42 (-3.56 to -1.29)
   Certainty: High heterogeneity (I2 61-75%), but the direction is consistent across sex and race subgroups; only studies of ≥4 weeks.
   BMJ, 2013 · checked 2026-10-06 · we read the abstract
2. ev-sodbp-02 · Meta-analysis or systematic review · systematic review and dose-response meta-analysis of RCTs · n = 12197
   Each 50 mmol reduction in 24 hour sodium excretion was associated with a 1.10 mm Hg (0.66 to 1.54; P<0.001) reduction in SBP and a 0.33 mm Hg (0.04 to 0.63; P=0.03) reduction in DBP. Reductions in blood pressure were observed in diverse population subsets examined, including hypertensive and non-hypertensive individuals. For the same reduction in 24 hour urinary sodium there was greater SBP reduction in older people, non-white populations, and those with higher baseline SBP levels.
   
   Who: randomized trials comparing sodium intakes in adults, intake measured by 24 hour urinary sodium
   Effect: per 50 mmol/day less sodium: SBP -1.10 mm Hg (0.66 to 1.54), DBP -0.33 mm Hg (0.04 to 0.63); overall SBP -4.26 mm Hg (3.62 to 4.89) for -130 mmol
   Certainty: Large database and dose measured by 24-hour urine; heterogeneity is present, the effect persists in subgroups.
   BMJ, 2020 · checked 2026-10-06 · we read the abstract
3. ev-sodbp-03 · Meta-analysis or systematic review · systematic review and dose-response meta-analysis of RCTs · n = 12197
   In trials of less than 15 days' duration, each 50 mmol reduction in 24 hour urinary sodium excretion was associated with a 1.05 mm Hg (0.40 to 1.70; P=0.002) SBP fall, less than half the effect observed in studies of longer duration (2.13 mm Hg; 0.85 to 3.40; P=0.002).
   
   Who: randomized trials comparing sodium intakes in adults, split by duration
   Effect: per 50 mmol/day less sodium: SBP -1.05 mm Hg (0.40 to 1.70) in trials under 15 days vs -2.13 mm Hg (0.85 to 3.40) in longer trials
   Certainty: Subgroup comparison by duration; beyond the 15-day limit no link to duration was found.
   BMJ, 2020 · checked 2026-10-06 · we read the abstract
4. ev-sodbp-04 · Meta-analysis or systematic review · dose-response meta-analysis of randomized trials (one-stage cubic spline mixed-effects model) · n = 85 trials
   The overall BP difference over the entire range of sodium exposure was more than 15 mmHg for SBP and nearly 10 mmHg for DBP.
   
   Who: 85 trials of at least 4 weeks with 24 hour urinary sodium, achieved intake 0.4 to 7.6 g/day, mostly adults with hypertension
   Effect: approximately linear; SBP difference over the full exposure range more than 15 mm Hg, DBP nearly 10 mm Hg; steeper in hypertension
   Certainty: Almost all studies have intermediate risk of bias (no description of randomization); the effect range is a model curve, not the mean effect of a single intervention.
   Circulation, 2021 · checked 2026-10-06 · we read the fulltext
5. ev-sodbp-05 · Meta-analysis or systematic review · Cochrane systematic review and meta-analysis of RCTs · n = 5982 normotensive (SBP), 3998 hypertensive (SBP)
   Normal blood pressure: SBP: mean difference (MD) -1.14 mmHg (95% confidence interval (CI): -1.65 to -0.63), 5982 participants, 95 trials; DBP: MD + 0.01 mmHg (95% CI: -0.37 to 0.39), 6276 participants, 96 trials. Hypertension: SBP: MD -5.71 mmHg (95% CI: -6.67 to -4.74), 3998 participants,88 trials; DBP: MD -2.87 mmHg (95% CI: -3.41 to -2.32), 4032 participants, 89 trials (all high-quality evidence).
   
   Who: white participants in RCTs of low versus high sodium diets, by blood pressure status
   Effect: normotensive SBP -1.14 mm Hg (-1.65 to -0.63), DBP +0.01; hypertensive SBP -5.71 mm Hg (-6.67 to -4.74), DBP -2.87 (-3.41 to -2.32); high-quality evidence
   Certainty: Also includes short (from days) studies with a large sodium difference, so it is not identical to He 2013; the review authors are skeptical of population recommendations.
   Cochrane Database Syst Rev, 2020 · checked 2026-10-06 · we read the abstract
6. ev-sodbp-06 · Meta-analysis or systematic review · Cochrane systematic review and meta-analysis of RCTs · n = 917 (cholesterol), 712 (triglyceride)
   During sodium reduction renin increased 1.56 ng/mL/hour (95%CI:1.39, 1.73) in 2904 participants (82 trials)...cholesterol increased 5.19 mg/dL (95%CI:2.1, 8.3) in 917 participants (27 trials); triglyceride increased 7.10 mg/dL (95%CI: 3.1,11.1) in 712 participants (20 trials)
   
   Who: RCTs of low versus high sodium diets reporting hormones and lipids
   Effect: renin +1.56 ng/mL/hour (1.39 to 1.73); cholesterol +5.19 mg/dL (2.1 to 8.3); triglyceride +7.10 mg/dL (3.1 to 11.1)
   Certainty: Also pools very short studies; He 2013 on RCTs of at least 4 weeks sees no significant change in lipids (ev-sodbp-07), and WHO 2012 considers lipid changes temporary. Clinical significance of the rise in renin and aldosterone is unknown.
   Cochrane Database Syst Rev, 2020 · checked 2026-10-06 · we read the abstract
7. ev-sodbp-07 · Meta-analysis or systematic review · Cochrane systematic review and meta-analysis of RCTs · n = 3230
   Salt reduction is associated with a small physiological increase in plasma renin activity, aldosterone, and noradrenaline and no significant change in lipid concentrations.
   
   Who: randomized trials of modest salt reduction lasting at least four weeks
   Effect: total cholesterol +1.9 mg/dL (-0.77 to 4.3; metric: 0.05 mmol/L, -0.02 to 0.11), LDL +0.05 (-0.01 to 0.12), triglycerides +0.04 (-0.02 to 0.09); renin +0.26 ng/mL/h (0.17 to 0.36)
   Certainty: The discrepancy with Graudal 2020 (ev-sodbp-06) is explained mostly by selection by duration; the hormonal shift is present in both.
   BMJ, 2013 · checked 2026-10-06 · we read the abstract
8. ev-sodbp-08 · Observational data · prospectively allocated diet order with crossover · n = 213
   Compared with the high-sodium diet, the low-sodium diet induced a decline in mean arterial pressure in 73.4% of individuals.
   
   Who: community adults aged 50 to 75 in 2 US cities, 64% Black, with normotension, controlled, uncontrolled or untreated hypertension; high sodium about 2200 mg added daily vs low sodium about 500 mg daily total
   Effect: median within-person mean arterial pressure change 4 mm Hg (IQR 0 to 8); after week one SBP difference 8 mm Hg (95% CI 4 to 11) high vs low sodium; 73.4% had a decline
   Certainty: The order of diets was assigned prospectively, but the abstract does not call it randomization, hence level C; a week per diet, without blinding; in the registry NCT04258332 is marked as completed.
   JAMA, 2023 · checked 2026-10-06 · we read the abstract
9. ev-sodbp-09 · Meta-analysis or systematic review · systematic review and instrumental variable meta-analysis of RCTs · n = 2885
   For every 100 mmol reduction in 24-hour urinary sodium excretion, systolic blood pressure decreased by 6.81 mm Hg (95% CI, 4.96-8.66), diastolic blood pressure decreased by 3.85 mm Hg (95% CI, 2.26-5.43), and mean arterial pressure decreased by 4.83 mm Hg (95% CI, 3.22-6.44).
   
   Who: hypertensive individuals on constant blood pressure lowering medication, RCTs of at least 2 weeks, median 28 days
   Effect: per 100 mmol/day less sodium: SBP -6.81 mm Hg (4.96 to 8.66), DBP -3.85 mm Hg (2.26 to 5.43); larger with beta-blockers, RAAS inhibitors and dual therapy
   Certainty: Median duration 28 days; effect differs by drug class.
   Hypertension, 2024 · checked 2026-10-06 · we read the abstract
10. ev-sodbp-10 · Meta-analysis or systematic review · Cochrane systematic review and meta-analysis of RCTs · n = 21414 (SBP), 784 (blood potassium)
    LSSS compared to regular salt probably reduce DBP on average (mean difference (MD) -2.43 mmHg, 95% confidence interval (CI) -3.50 to -1.36; 20,830 participants, 19 RCTs, moderate-certainty evidence) and SBP (MD -4.76 mmHg, 95% CI -6.01 to -3.50; 21,414 participants, 20 RCTs, moderate-certainty evidence) slightly.
    
    Who: adults in RCTs comparing low-sodium salt substitutes with regular salt; all trials excluded people in whom extra potassium is known to be harmful
    Effect: SBP MD -4.76 mm Hg (-6.01 to -3.50), DBP MD -2.43 (-3.50 to -1.36), moderate certainty; blood potassium +0.12 mmol/L (0.07 to 0.18)
    Certainty: Moderate certainty; no data on pregnant women and on people for whom potassium is harmful; in children the data are very uncertain.
    Cochrane Database Syst Rev, 2022 · checked 2026-10-06 · we read the abstract
11. ev-sodbp-11 · Meta-analysis or systematic review · Cochrane systematic review and meta-analysis of RCTs · n = 34961 adults, 92 children
    Evidence is limited for adults without elevated blood pressure, and there is a lack of evidence in pregnant women and people in whom an increased potassium intake is known to be potentially harmful, limiting conclusions on the safety of LSSS in the general population.
    
    Who: trials of low-sodium salt substitutes in adults, children and pregnant women
    Effect: no evidence in pregnancy or in people at risk of hyperkalemia; safety in the general population not established
    Certainty: This is the boundary of knowledge, not a finding of harm.
    Cochrane Database Syst Rev, 2022 · checked 2026-10-06 · we read the abstract
12. ev-sodbp-12 · Randomized controlled trial(s) · open-label cluster-randomized trial · n = 20995
    The rate of stroke was lower with the salt substitute than with regular salt (29.14 events vs. 33.65 events per 1000 person-years; rate ratio, 0.86; 95% confidence interval [CI], 0.77 to 0.96; P = 0.006), as were the rates of major cardiovascular events (49.09 events vs. 56.29 events per 1000 person-years; rate ratio, 0.87; 95% CI, 0.80 to 0.94; P<0.001) and death (39.28 events vs. 44.61 events per 1000 person-years; rate ratio, 0.88; 95% CI, 0.82 to 0.95; P<0.001).
    
    Who: persons from 600 villages in rural China with a history of stroke or aged 60 or older with high blood pressure
    Effect: stroke rate ratio 0.86 (0.77 to 0.96); major cardiovascular events 0.87 (0.80 to 0.94); death 0.88 (0.82 to 0.95); hyperkalemia serious adverse events 1.04 (0.80 to 1.37)
    Certainty: Open-label, cluster; a high-risk population with very high salt intake; selection of people without renal failure and potassium drugs limits transfer.
    N Engl J Med, 2021 · checked 2026-10-06 · we read the abstract
13. ev-sodbp-13 · Observational data · systematic review and meta-analysis of experimental and observational studies · n = 3406
    The meta-analysis of 18 experimental and observational studies (including 3406 participants) with sodium intake and blood pressure measurement methods of high quality showed that, for every additional gram of sodium intake per day, systolic blood pressure increased by 0.8 mm Hg (95% CI: 0.4, 1.3) and diastolic blood pressure by 0.7 mm Hg (95% CI: 0.0, 1.4).
    
    Who: children and adolescents 0 to 18 years; 18 experimental and observational studies with high-quality sodium and blood pressure methods
    Effect: +0.8 mm Hg SBP (0.4 to 1.3) and +0.7 mm Hg DBP (0.0 to 1.4) per extra g/day sodium
    Certainty: Observational and experimental studies pooled, hence level C; AHRQ 2018 considers the effect on systolic blood pressure in children not established (ev-sodbp-16).
    Int J Epidemiol, 2018 · checked 2026-10-06 · we read the abstract
14. ev-sodbp-14 · Position of an expert body · WHO guideline · n = -
    WHO recommends a reduction to <2 g/day sodium (5 g/day salt) in adults (strong recommendation). WHO recommends a reduction in sodium intake to control2 blood pressure in children (strong recommendation).
    
    Who: adults and children, WHO global guideline
    Effect: adults < 2 g/day sodium (5 g/day salt), strong recommendation; children adjusted downward by energy requirements
    Certainty: Position backed by WHO's own systematic reviews; confirmed in the 2025 guideline on salt substitutes.
    WHO, 2012, Guideline: sodium intake for adults and children · checked 2026-10-06 · we read the section
15. ev-sodbp-15 · Position of an expert body · WHO guideline · n = -
    The recommendation in this guideline is intended for adults in the general population and excludes individuals with kidney impairments or with other circumstances or conditions that might compromise potassium excretion (e.g. those taking potassium-sparing diuretics and potassium supplements). The recommendation does not apply to children or pregnant women.
    
    Who: adults in general populations, WHO guideline on lower-sodium salt substitutes
    Effect: conditional recommendation for adults; excludes kidney impairment, potassium-sparing diuretics, potassium supplements, children, pregnancy
    Certainty: A conditional recommendation; the exclusion is due to the risk of hyperkalemia, which was not tested in the studies (ev-sodbp-11).
    WHO, 2025, Use of lower-sodium salt substitutes: WHO guideline summary · checked 2026-10-06 · we read the section
16. ev-sodbp-16 · Meta-analysis or systematic review · agency systematic review · n = -
    Evidence was insufficient to determine whether race/ethnicity moderate the effect of sodium reduction on blood pressure. Evidence suggests that sodium reduction may not lower systolic BP in children (low strength of evidence), but evidence based on a sensitivity analysis that omitted high or unclear RoB studies suggests a significant effect on diastolic BP.
    
    Who: adults and children in RCTs of at least 4 weeks and prospective cohorts, AHRQ comparative effectiveness review
    Effect: children: may not lower SBP (low strength); race/ethnicity as moderator: insufficient evidence
    Certainty: An agency systematic review (T2, level A by the standard); strength of evidence downgraded because of inconsistency and heterogeneity.
    AHRQ, 2018, Sodium and Potassium Intake: Effects on Chronic Disease Outcomes and Risks (Comparative Effectiveness Review 206) · checked 2026-10-06 · we read the section