How common is vitamin B-12 deficiency?
Level 5 - mechanism / opinion, no new human data
Narrative review of epidemiological surveys and physiological mechanisms without systematic search methodology
PubMed 19116323 · doi:10.3945/ajcn.2008.26947A
What was done
Narrative review of existing literature and population survey data assessing the prevalence, causes, and demographic patterns of vitamin B-12 deficiency, as well as the potential efficacy of vitamin B-12 flour fortification.
What was found
Surveys from the United States and the United Kingdom indicate that approximately 6% of individuals aged ≥60 years are vitamin B-12 deficient (plasma vitamin B-12 < 148 pmol/L), with prevalence increasing with age; approximately 20% have marginal status (148–221 pmol/L). Deficiency is more widespread in developing countries across all age groups, primarily due to low dietary intake of animal-source foods. In older populations, food-bound cobalamin malabsorption linked to gastric atrophy is the predominant cause, though free vitamin B-12 in fortified foods remains absorbable for most elderly individuals.
Why it matters
Synthesizes epidemiological data demonstrating that vitamin B-12 deficiency and marginal status are common in older adults in high-income nations and widespread across developing populations, providing a rationale for population-level flour fortification.
Limits
Narrative review design without systematic search or meta-analytic methods. Specific study counts and total participant numbers are not provided in the abstract, and intervention trials testing the efficacy of flour fortification in populations with gastric atrophy remain lacking.
Cited by
- supports The human body's capacity to absorb vitamin B12 decreases with age.