Vitamin B12 deficiency in older people and whether screening helps
What it found
Low vitamin B12 is common in older people, but blood tests to find it are imperfect.
The authors say pills work as well as injections for treatment.
What they found
Studies in people
How common it is
Between 5% and 40% of older people have low vitamin B12, depending on which blood test cut-off is used. In one local study of 2096 care-home residents over 65, about 35% had low levels. Among older people living at home, only 6.6% did.
Pills work like injections
Taking vitamin B12 by mouth works as well as getting shots, even for people whose stomachs cannot absorb it normally. Doctors suggest a high daily amount for a month, then a smaller daily amount to keep levels up.
Heart and blood vessels
A trial gave 3680 adults with prior stroke a mix of B vitamins for two years. Their homocysteine levels dropped, but they did not have fewer strokes or heart problems than those who got no vitamins.
Mood and thinking
In a group of 3884 older people, those with low vitamin B12 were about 70% more likely to have depression. Another study of 700 disabled women found low levels doubled the chance of severe low mood.
Other findings
Blood tests are imperfect
There is no single agreed blood level that proves someone lacks vitamin B12. Extra tests for related chemicals can help, but they sometimes give wrong results and labs use different ranges.
What the authors conclude
- They support checking older people for low vitamin B12 because it is common and treatment is straightforward.
- They note that current lab tests have limits, making it hard to pick one reliable screening tool.
- They advise treating any shortage quickly to prevent lasting nerve damage.
How it was done
Older people often lack enough vitamin B12 because their stomachs absorb less of it from food. The signs are easy to miss, yet the harm can be serious if nobody spots it.
The author gathered and examined published research on how common low vitamin B12 is in older adults. They looked at how doctors test for it, what causes it, and how well treatments work. No new patients were enrolled for this work.
What it can’t tell you
- This work gathers past studies rather than testing a new idea, so it cannot prove cause and effect.
- Some findings come from animal models of brain disease, which may not match what happens in people.
- A short two-year vitamin trial might be too brief to show heart benefits.
Who paid
- Authors work at
- Caritas Medical Centre, Hong Kong
The paper
- Title
- Vitamin B12 deficiency in the elderly: is it worth screening?
- Type
- ReviewThe authors read earlier studies and describe what they found. It isn’t a new study.
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Wong CW (2015). Vitamin B12 deficiency in the elderly: is it worth screening?. Hong Kong medical journal = Xianggang yi xue za zhi. doi:10.12809/hkmj144383Free full textPubMed 25756278DOI
Summary written 1 Oct 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error