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Open WellbeingWhat the studies actually measured

Heart and blood pressure

Sodiumand Diastolic blood pressure

Both sources here measured lower diastolic blood pressure.

How sure anyone can be

High certainty, level 4 of 4

Further research is very unlikely to change this.

The most certain of the two findings here; each record carries its own.

The numbers reported

One source’s range, drawn against its own line of no difference and scaled to its own numbers.

-3.41-2.87 mmHg-2.32

This range stays on one side of the no-difference line.

Bar the confidence interval — the range the true effect is likely to sit inNotch the number the source reportedLine where there would be no difference at all

Two sources, newest first

What we read is the published abstract, not the full paper, so a blank below may still be printed in the paper itself. A fixed rule worked this out from the source’s own fields. Nobody checked this rating by hand.

  • Systematic review, 2020 · 89 studies pooled · 4,032 participants

    High certainty, level 4 of 4

    Effects of low sodium diet versus high sodium diet on blood pressure, renin, aldosterone, catecholamines, cholesterol, and triglyceride.

    Cochrane Database Syst Rev. 2020;12(12):CD004022. doi:10.1002/14651858.CD004022.pub5. PMID:33314019.

    This source later carried a notice: Update of Cochrane Database Syst Rev. 2017 Apr 09;4:CD004022. doi: 10.1002/14651858.CD004022.pub4. The number below is exactly as the source gave it.

    Number reported
    -2.87 mmHg
    Which way it went
    Lower
    Likely range
    -3.41 to -2.32
    Source’s own words
    mmHg diastolic BP, mean difference on a low-sodium versus high-sodium diet
    Who was studied
    Adult with hypertension
    Compared with
    high sodium diet
    Amount taken
    65 to 203 mmol/d sodium (reduced from 203 to 65 mmol/day)
    For how long
    Not in the abstract
    Disagreement between studies
    Not in the abstract
    Kind of record
    Journal article
    How this rating was reachedstarts at High, and nothing brought it down
    1. Starts at High
    2. Ends at HighNothing brought this one down a step.
    Checked, nothing to step it down for
    risk of bias, indirectness and imprecision
    Inconsistency
    No high disagreement reported between the 89 studies it pooled

    AI-reviewed & signed — an AI agent re-read this finding against the saved source and checked that the quote, the numbers, the units and the direction match it. No person read it. The owner authorised the agent to sign the batch with the owner's key, and every build rechecks that signature against these exact bytes.

    Read the abstract on PubMed

  • Systematic review, 2013

    Low certainty, level 2 of 4

    Effect of longer term modest salt reduction on blood pressure: Cochrane systematic review and meta-analysis of randomised trials.

    BMJ. 2013;346:f1325. doi:10.1136/bmj.f1325. PMID:23558162.

    Number reported
    -2.06 mmHg
    Which way it went
    Lower
    Likely range
    -2.67 to -1.45
    Source’s own words
    mm Hg diastolic BP, mean change reduced salt versus usual salt
    Who was studied
    Not stated in the abstract
    Compared with
    usual salt
    Amount taken
    Not in the abstract
    For how long
    Not in the abstract
    Disagreement between studies
    I(2)=68%
    Kind of record
    Journal article
    How this rating was reachedstarts at High, 2 steps down: risk of bias and imprecision
    1. Starts at High
    2. Risk of bias brought it down to Moderatethe abstract reports no risk-of-bias or quality appraisal, so study limitations cannot be ruled outNot in the abstract
    3. Imprecision brought it down to Lowthe abstract does not state how many participants were pooledNot in the abstract
    4. Ends at Low2 steps down.
    Checked, nothing to step it down for
    indirectness
    Inconsistency
    No disagreement reported, and no count of studies behind it

    Imprecision stops at the first check that applies; others may apply too.

    Source saved; quote checked byte-for-byte against it by software; no signature.

    Read the abstract on PubMed

What is still missing from these readings

  • One do not say how many people took part.
  • Amount taken — One of Two readings: Not in the abstract.
  • For how long — Not in the abstract.

Something nobody wrote down is never a zero and never a guess.

Still to read for Sodium

Nine of the 18 things on our list for Sodium have no reading here yet:

  • All-cause mortality
  • Bone mineral density
  • Estimated GFR
  • Hydration Tracking
  • Kidney Stone Risk
  • LDL cholesterol
  • Left ventricular mass
  • Muscle soreness
  • Urinary calcium (24-hour)

Still to read means nobody here has got to it, not that it was tried and did nothing or that no research exists. A pairing on no list is not a gap: we never set out to read it.

Read next

This is a library, not advice. No recommendation, no dose, no diagnosis, no ranking. We never ask about your symptoms, and nothing here is tailored to you.