This paper provides an overview of dose-response evidence relevant for estimating vitamin B12 requirements of healthy adults and elderly people, considering different indicators of health: vitamin B12 body stores, cognitive function, bone health, and biomarkers of vitamin B12 status.
Vitamin B12 intakes needed to compensate daily losses may range from 3.8 to 20.7 μg/day depending on the assumptions used. The current evidence-base on cognitive function and bone health is too limited to estimate vitamin B12 requirements. Evidence from controlled trials and observational studies on vitamin B12 intake and biomarkers of vitamin B12 status provided estimates of average requirements between 0.07 and 4.1 μg/day, depending on the type of data and selected cut-off value indicating adequate vitamin B12 status. To improve estimates of requirements, advanced models for integrating the evidence are needed with assumptions consistent with the strengths and limitations of epidemiological and physiological studies.