The Study
Effect of dose and duration of reduction in dietary sodium on blood pressure levels: systematic review and meta-analysis of randomised trials
This study looked at lots of experiments where people were randomly told to eat less salt, and found that when they did, their blood pressure usually went down. It’s like testing if eating less candy makes you less hyper — and it found that yes, less salt really does help lower blood pressure.
Analysis score
Maximum 100 for a systematic review with meta-analysis.
Where the score came from
When people eat less salt, their blood pressure goes down — and the more salt they cut, the more it drops. This works for everyone, but older people, non-white people, and those with high blood pressure see the biggest drops. If you cut salt for just a few days, you don’t see the full effect — it takes weeks.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 573 / 100
Quality score
The highest quality evidence. Systematic reviews and meta-analyses that pool randomized controlled trials, giving the most reliable summary of experimental evidence.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes — a 4–5 mm Hg drop in systolic BP reduces stroke and heart attack risk by 10–20%, making this a major public health benefit.
- 2Cutting salt by 130 mmol/day lowers BP by 4.26 mm Hg (systolic) and 2.07 mm Hg (diastolic).
- 3Every 50 mmol cut lowers systolic BP by 1.10 mm Hg and diastolic by 0.33 mm Hg.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
The BMJ
Year
2020
Authors
Liping Huang, K. Trieu, S. Yoshimura, B. Neal, M. Woodward, N. Campbell, Qiang Li, D. Lackland, A. Leung, C. Anderson, G. MacGregor, F. He
Related Content
Claims (7)
Cutting down on salt can lower your blood pressure, and the more salt you cut, the more your blood pressure drops—especially if it was already high to begin with.
Cutting back on salt in your diet lowers your blood pressure—on average, by about 4 points for the top number and 2 points for the bottom number.
For every 1/4 teaspoon of salt you cut out of your diet, your systolic blood pressure drops by about 1 point, and your diastolic by about 1/3 of a point.
If you cut salt for just a week or two, your blood pressure doesn’t drop as much as it will if you keep it low for a month or more—it takes time for the full effect to show up.
Even if your blood pressure is normal, cutting back on salt still helps lower it a little—which could help prevent high blood pressure as you get older.
People who are older, Black or Asian, or already have high blood pressure see a bigger drop in their blood pressure when they cut salt than younger, white, or healthy people do.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.