Vitamin B12 and Cognitive Decline

By: Dr. Pascale Michelon

What is the relationship between vitamins and cognitive health? Should we take vitamin supplements to increase our brain functions? What is the evidence? A recent study, published in the journal Neurology, indicates that low levels of vitamins B12 may be associated with low cognitive scores and brain volume.

The study
The study involved 121 people age 65 and older whose blood was drawn to measure levels of vitamin B12 and B12-related metabolites that can indicate a B12 deficiency. Four and a half years later on average, the participants’ brains were scanned to both measure their total brain volume and look for any signs of brain damage. The participants’ memory and other cognitive skills were also assessed at that time.
The results of the study showed that having high levels of four of five markers for vitamin B12 deficiency was associated with lower scores on the cognitive tests and a smaller total brain volume.

What does it mean?
First of all, note that the level of vitamin B12 itself in the blood was not associated with cognitive problems or loss in brain volume. Only biological markers of vitamin B12 deficiency were. So it is not easy to assess whether someone is deficient in vitamin B12, especially when looking only at the level of vitamin B12 itself.
Second, it is not because B12 deficiency is associated with lower cognitive skills that increasing levels of B12 through diet or supplements could increase cognitive skills. There is no evidence for this yet. Moreover, the causes of cog­ni­tive decline are prob­a­bly too com­plex to be halted with a sin­gle vit­a­min supplement.

In sum
To date, no sup­ple­ment has been shown to effec­tively slow down cog­ni­tive decline and post­pone Alzheimer’s dis­ease symp­toms. It seems that there is no magic pill to brain health and no sin­gle solu­tion. Your best bet so far is a brain-healthy lifestyle includ­ing at least phys­i­cal exer­cise, bal­anced diet, men­tal stim­u­la­tion and brain train­ing, stress man­age­ment, and social engagement.

Tangney et al. (2011). Vitamin B12, cognition, and brain MRI measures: A cross-sectional examination. Neurology, 77:1276-1282.

Learn more about the link between diet/supplements and cognitive health here:

4 comments on “Vitamin B12 and Cognitive Decline

  1. Pingback: Is Fish Good for the Brain? | The Memory Practice

  2. Hi and thanks for spending some time to explain the terminlogy to the starters!

  3. Elliptical machine on said:

    I suggest you to add a facebook like button!

  4. Jen S. on said:

    Thanks for the interesting read. I have a particular interest in vitamin b12 and vitamin b12 deficiency. It does make sense that individuals would see a drop based on low levels of b12. The smaller total brain volume was a bit of a surprise.

    Thanks again,


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