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The Balance of Health
Health

Claim

Vegans need vitamin B12 from supplements or fortified foods; without one, deficiency is common and can cause lasting harm.

Yes. This is the one nutrient a vegan diet cannot supply on its own. A cheap supplement solves it.

Last reviewed
Reviewer
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Status
sample

Sample data. The figures and sources on this page are demonstration records showing how evidence will be presented. They are approximate and have not yet been through our review process. Read about how we will verify evidence.

Strong evidenceHow ratings work

Why this rating: Consistent across many surveys and supported by a clear biological mechanism.

Supported by multiple systematic reviews or large, consistent studies using different methods, with few plausible alternative explanations.

52% (varies widely by study)
Vegans with low B12 status in studies of unsupplemented groupsMultiple countries, 2013. Source: Pawlak et al. (2013). SampleWide range reflects different thresholds and populations. The consistent finding is that unsupplemented vegans are at high risk.

Explanation

B12 is made by microbes and reaches humans mainly through animal foods. Plant foods do not reliably contain it.

Deficiency develops slowly and can damage nerves and blood formation. Supplements and fortified foods are effective and inexpensive.

Limitations
  • Deficiency rates vary with the marker used and how long people have been vegan.
Methodology
  • Systematic review of B12 status studies in vegetarian and vegan populations.

Sources for this claim

Each source links to our record of what it found, its limitations and what we used it for, with a link to the original.

  1. 1
    How prevalent is vitamin B12 deficiency among vegetarians?

    Roman Pawlak, Scott Parrott, Sudha Raj et al. (2013). Nutrition Reviews.

    Systematic ReviewSystematic ReviewStrong evidenceSampleView original ↗