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Evidence to Improve Care

Vitamin B12 and Cognitive Function


Ontario Health Technology Advisory Committee Recommendations

  • The Ontario Health Technology Advisory Committee recommends that serum vitamin B12 testing be restricted to those with macrocytic anemia or malabsorption.

  • The Ontario Health Technology Advisory Committee recommends against serum vitamin B12 testing for the purpose of investigating dementia or cognitive impairment and for vague presentations such as alopecia, dizziness, and fatigue.

  • The Ontario Health Technology Advisory Committee recommends oral vitamin B12 be used instead of intramuscular vitamin B12 unless there is evidence of malabsorption.

Read the full OHTAC Recommendation report



Vitamin B12 is an essential vitamin. Low levels of vitamin B12 can lead to a type of anemia (low levels of red blood cells) and to problems with the nervous system, such as cognitive impairment (trouble reasoning or thinking). There are four main reasons why people have low levels of vitamin B12:

  • They do not get enough in their diet

  • Their body doesn’t absorb it properly (malabsorption)

  • They have intestinal problems such as Crohn’s disease

  • They take certain drugs, such as metformin.


Health Quality Ontario Reviews Vitamin B12 and Cognitive Function

Health Quality Ontario looked at whether low vitamin B12 led to cognitive impairment, and whether vitamin B12 supplements improved cognitive impairment. It also looked at the best way of delivering vitamin B12: by mouth (oral) or by injection (intramuscular).


Vitamin B12 and Cognitive Function: An Evidence-Based Analysis (PDF)
November 2013


Vitamin B12 Intramuscular Injections Versus Oral Supplements: A Budget Impact Analysis (PDF)
November 2013


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The Ministry of Health and Long-Term Care endorses this recommendation.

The Ministry of Health and Long-Term Care has provided the following response: The Ministry removed the vitamin B12 test from the Ontario laboratory requisition form in November 2012. The test can still be requested if needed and remains an insured service with no restrictions on its use.

The Ministry agrees with the recommendation regarding oral vitamin B12 and notes that intramuscular injections of B12 remain publicly funded for those with evidence of malabsorption that are eligible for the Ontario Drug Benefit.




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