From the Research
The recommended serum level of Vitamin B12 for adults is above 300 pmol/L, as levels below this threshold may indicate deficiency and increase the risk of anemia, fatigue, and neurological problems. This recommendation is based on the most recent and highest quality study available, which found that oral vitamin B12 supplementation can effectively improve vitamin B12 deficiency in patients with pernicious anemia 1. The study demonstrated that oral cyanocobalamin supplementation at a dosage of 1000 μg/d can significantly improve plasma vitamin B12 concentrations, with 88.5% of patients no longer deficient in vitamin B12 after 1 month of treatment.
Key points to consider:
- Vitamin B12 is essential for DNA synthesis, red blood cell formation, and proper neurological function
- The body cannot produce B12 on its own, so it must be obtained through diet or supplements
- Good dietary sources include animal products like meat, fish, eggs, and dairy
- Vegetarians and vegans may need to rely on fortified foods or supplements to meet their B12 needs
- Adults over 50 years of age often have decreased absorption of B12 from food sources due to reduced stomach acid production, so they may benefit from taking supplements or consuming fortified foods to ensure adequate intake
Other studies have also investigated the efficacy of oral vitamin B12 supplementation, including a study that found that daily doses of 647 to 1032 μg of cyanocobalamin were associated with 80% to 90% of the estimated maximum reduction in plasma methylmalonic acid concentration 2. Additionally, a systematic review and network meta-analysis found that all routes of administration of vitamin B12 (oral, intramuscular, and sublingual) can effectively increase vitamin B12 levels, with no significant differences between them 3. However, the most recent and highest quality study available 1 provides the strongest evidence for the recommended serum level of Vitamin B12.