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In my previous post, we talked about the role of iron in formation of blood cells. You might’ve seen your doctor check Vitamin B12 and folate/folic acid levels when working up anemia.
So let’s dive into some of the important practical aspects of vitamin B12 and folic acid
A quick refresher of the biochemistry first!
Vitamin B12
Vitamin B12 or cobalamin is an essential co-enzyme for 2 enzymes. These enzymes are
1- Cytoplasmic methionane synthase - involved in conversion of homocysteine to methionine which inturn is involved in folate metablolism > purine and pyrimidine synthesis
2- methyl malonyl Co-A mutase : involved in conversion of methyl malonyl CoA with succinyl CoA and involved in the Krebs’ cycle in the mitochondria
3- Vitamin B12 is also needed for myelin sheath formation around the nerves
Folate or Folic acid
Folate is reduced to tetrahydrofolate and is critical in 1 carbon metabolism and in purine and pyrimidine synthesis
This is a hypersegmented neutrophil and its the classic finding in B12 deficiency. The neutrophil’s nucleus has too many lobes >5 and that is not normal!
Image credit: ASH Image Bank
Bottom line is: B12 and Folate are essential to make DNA and B12 additionally is important in keeping the nervous system healthy!
Now let’s get to the practical aspects
Who needs B12 supplementation? Here are some common clinical scenarios wherein B12 supplementation is warranted
Levels are checked and they’re below 200 pg/mL
Folks who’ve had gastric bypass surgery
Folks who have malabsorption diseases such as celiac disease or sprue or Crohn’s disease, pernicious anemia
Folks who are strict vegan/vegetarian
Who needs folate supplementation? Here are some common clinical scenarios wherein folate supplementation is warranted
Levels are checked and they are <2 ng/mL
Women who are pregnant or planning a pregnancy
People who have hemolytic anemia such as sickle cell disease
Folks that have a long history of chronic alcohol use
Folks with malabsorption diseases mentioned above
Lastly, how much and how long should you supplement for?
B12 supplementation: 1000 - 2000 mcg/day by mouth or 1000 mcg intramuscular (initially daily then weekly and monthly) if you have pernicious anemia.
Continue supplementation until the blood counts recover (~3 months) or if neurologic symptoms show improvement (~12 months). Excess B12 is excreted in the urine so you cannot overdose on it!
Folate supplementation: Recommended daily allowance is 400 micrograms/day however the most common formulations available are 1 mg or 5 mg. With proven folate deficiency 1 mg supplementation for ~4 months is needed for hematologic recovery.
Thank you for reading and I hope this was useful! Reply to this email to let me know what other topic would be useful for you and I will feature it in a future edition!
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Disclaimer: The content in this newsletter is for educational purposes only and should not be considered medical advice. Subscription to this newsletter does not establish a doctor-patient relationship. Always consult your physician with specific questions regarding your health
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