Sodium intake and blood pressure across 85 trials in people
What it found
Cutting sodium lowered both the top and bottom blood pressure numbers in a nearly straight line, with no sign of a minimum level where the benefit stopped.
This was seen across 85 trials in people.
What they found
Studies in people
Overall blood pressure drop
Across all the trials, cutting sodium lowered both the top and bottom blood pressure numbers. For every 1 g/d drop in sodium output, the top number fell by 2.42 mm Hg and the bottom number by 1.01 mm Hg.
People with high blood pressure
The blood pressure drop was much larger in people who already had high blood pressure. At very high sodium levels, their top number was over 10 mm Hg higher compared with low sodium levels.
People without high blood pressure
People without high blood pressure also saw lower readings when they cut sodium. Their top number rose by about 4 mm Hg when comparing 6 g/d to 2 g/d of sodium.
Diet changes versus pills
Changing the whole diet lowered blood pressure more than just adding or removing sodium pills. This was most noticeable at very low sodium levels under 2 g/d.
Short and long trials
The link between sodium and blood pressure held up in trials lasting 12 weeks or more. The effect was slightly smaller than in shorter trials but still followed a straight line.
What the authors conclude
- They found an almost straight-line link between how much sodium people take in and their blood pressure, with no sign that the benefit stops at low levels.
- They say advice to eat less sodium applies to adults with and without high blood pressure, though the expected drop is larger for those whose blood pressure is already high.
- They note that progressively bigger drops in blood pressure can be expected as sodium intake falls toward 1 to 1.5 g/d.
How it was done
Scientists already knew that less sodium lowers blood pressure, but they were unsure about the exact shape of that link. They wanted to see if there was a point where eating even less sodium stopped helping, especially for people without high blood pressure.
They combined results from 85 trials involving more than 10 000 adults. The studies lasted from 4 weeks to 36 months, and daily sodium intake ranged from 0.4 to 7.6 g/d. Some participants had high blood pressure and some did not.
What it can’t tell you
- These trials measured blood pressure, so they cannot directly show whether cutting sodium prevents heart attacks or strokes.
- Some estimates at the very highest and lowest sodium levels were based on few studies, making them less certain.
- Because these are combined trial results, they reflect what happened over weeks or months rather than a lifetime of eating habits.
Who paid
- Funding
- Funded by NIGMS NIH HHS (from the PubMed record).
- Authors work at
- University of Modena and Reggio Emilia, M.V.; Tulane University School of Public Health and Tropical Medicine, LA (P.K.W.); National and Kapodistrian University of Athens, Greece (A.N.)
The paper
- Title
- Blood Pressure Effects of Sodium Reduction: Dose-Response Meta-Analysis of Experimental Studies
- Type
- Meta-analysis
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Filippini T, Malavolti M, Whelton PK, Naska A, Orsini N, Vinceti M (2021). Blood Pressure Effects of Sodium Reduction: Dose-Response Meta-Analysis of Experimental Studies. Circulation. doi:10.1161/CIRCULATIONAHA.120.050371Free full textPubMed 33586450DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error