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Open WellbeingWhat the studies actually measured

Vitamin and mineral levels

Riboflavin (vitamin B2)and Hemoglobin

Only one source here so far, and it reported mixed results for hemoglobin.

How sure anyone can be

Very low certainty, level 1 of 4

Any estimate here is very uncertain.

The numbers reported

No number has been put on this yet. One source recorded only which way the numbers went — for now, that is all we have here.

One source, 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.

  • Randomised trial, 2011

    Very low certainty, level 1 of 4

    Correcting a marginal riboflavin deficiency improves hematologic status in young women in the United Kingdom (RIBOFEM).

    Am J Clin Nutr. 2011;93(6):1274-84. doi:10.3945/ajcn.110.008409. PMID:21525198.

    Number reported
    Not in the abstract
    Which way it went
    Mixed results
    Likely range
    Not in the abstract
    Source’s own words
    no between-group mean difference in haemoglobin reported in the abstract; results given as within-supplement correlations and a tertile comparison
    Who was studied
    Adult with riboflavin deficiency
    Compared with
    placebo
    Amount taken
    2 to 4 mg/d riboflavin
    For how long
    56 days
    Disagreement between studies
    Not in the abstract
    Kind of record
    Journal article
    How this rating was reachedstarts at High, 3 steps down: risk of bias, imprecision and inconsistency
    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 reports no confidence interval for the estimateNot in the abstract
    4. Inconsistency brought it down to Very lowpooled studies disagree on the direction of effectReported in the abstract
    5. Ends at Very low3 steps down.
    Checked, nothing to step it down for
    indirectness

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

    AI review could not confirm it — an AI agent re-read this finding against the saved source and at least one check failed. The batch record names the check and quotes the sentence that caused the doubt. No person read it.

    Read the abstract on PubMed

What is still missing from these readings

  • No number at all, only which way it went.
  • One gives no likely range, so how precise that number is is unknown.
  • One do not say how many people took part.

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

Nothing left on our list for Riboflavin (vitamin B2)

All two things on our list for Riboflavin (vitamin B2) have been read. That is rare here.

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.