Oral vitamin B12 for pernicious anemia in 26 patients
What it found
In 26 people with pernicious anemia, a daily oral dose of 1000 micrograms of cyanocobalamin corrected vitamin B12 deficiency in most within a month and kept it corrected for a year.
What they found
Studies in people
Deficiency corrected
After 1 month of oral vitamin B12, 88.5% of patients were no longer deficient. By the end of the 12-month follow-up, no patients showed vitamin B12 deficiency.
Blood vitamin B12 rose
Plasma vitamin B12 rose from 148 pmol/L at the start to 407 pmol/L after 1 month. The improvement lasted throughout the 12-month follow-up.
Homocysteine and MMA fell
Plasma homocysteine dropped from 18.6 to 13.5 μmol/L and plasma methylmalonic acid dropped from 0.56 to 0.24 pmol/L after 1 month. These improvements also persisted over 12 months.
Time to reverse symptoms
The median time to reverse initial vitamin B12 deficiency abnormalities ranged from 1 month for hemolysis to 4 months for mucosal symptoms.
What the authors conclude
“Oral supplementation with 1000 μg/d of cyanocobalamin has been shown to improve vitamin B12 deficiency in PA.”
Also in their conclusions
- They conclude that oral supplementation with 1000 μg/d of cyanocobalamin has been shown to improve vitamin B12 deficiency in PA.
How it was done
Vitamin B12 absorption is blocked in pernicious anemia because the body lacks intrinsic factor. Injections have been the standard treatment, and oral supplements are not commonly prescribed because few studies have tested whether they work.
They enrolled 26 people newly diagnosed with vitamin B12 deficiency caused by pernicious anemia. Everyone took 1000 micrograms of cyanocobalamin by mouth each day, and their blood and urine markers were checked over 1 year.
What it can’t tell you
- We summarised it from the abstract only.
- This was a small study of 26 people with pernicious anemia, so the results may not apply to everyone with the condition.
- The study did not compare oral vitamin B12 with injections, so it cannot show whether one works better than the other.
Who paid
- Authors work at
- University Hospital, France; Angers University, France; University of California, United States
The paper
- Title
- Oral vitamin B12 supplementation in pernicious anemia: a prospective cohort study
- Type
- Study
- Evidence
- Studies in people
- Summarised from
- Abstract only
- Cite
- Lacombe V, Vinatier E, Roquin G, et al (2024). Oral vitamin B12 supplementation in pernicious anemia: a prospective cohort study. The American journal of clinical nutrition. doi:10.1016/j.ajcnut.2024.05.019PubMed 38797248DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error