Case Reports
A Swedish study analyzed the effects of several B vitamins, including 0.5 mg/d of B12 vs placebo on mood in 65 celiac patients on a gluten-free diet who had borderline/low normal B12 levels (>191 pg/mL).5 Patients who scored low on a measure of psychological well-being at the beginning of the study and who received B12 experienced significant improvements in anxiety and depressed mood compared to those who received placebo.
Our patient
Because neurologic and psychiatric symptoms require assured compliance and urgent treatment, our patient received vitamin B12 parenterally as cyanocobalamin 1 mg/mL. She was given this dosage intramuscularly once a day for 5 days, then once a week for 4 weeks. She will continue to receive it once a month indefinitely.
The patient was advised that if she wished to switch to oral therapy, she could do so after several months of parenteral treatment, as long as she had close follow-up with frequent B12 measurements to assure that she was absorbing oral therapy. Her anxiety and mood symptoms resolved within one month, and her disequilibrium was almost entirely resolved within 3 months of treatment.
THE TAKEAWAY
Although more common in older patients, vitamin B12 deficiency can also affect younger patients. “Low normal” B12 levels (200-400 pg/mL) may affect psychological well-being.
Consider testing serum B12 and a second biomarker—such as homocysteine or methylmalonic acid, if indicated—in patients who present with depressed mood, anxiety, cognitive symptoms, and/or fatigue. Vitamin B12 supplementation can be administered orally and has no major adverse effects.