Background: Vitamin B12 deficiency is common after bariatric surgery. Vitamin B12 is a poor predictor of functional vitamin B12 status, since deficiencies might even occur within the reference limits. Therefore, vitamin B12 deficiencies with serum vitamin B12 levels are between 140 and 200 pmol/L remain undetected. Methylmalonic acid (MMA), however, will detect these deficiencies as accumulates due to functional intracellular vitamin B12 deficiencies. MMA is a relative expensive analysis and is therefore not generally available. To lower the costs, we only request MMA when vitamin B12 levels are between these levels. As a result, more biochemical deficiencies are found. However, it was not known whether bariatric patients with vitamin B12 levels between 140 and 200 pmol/L would benefit from supplementation.
Method: Bariatric patients with vitamin B12 levels between 140 and 200 pmol/L with (n = 45) and without (n = 45) intramuscular hydroxocobalamin injections were compared.
Results: Treated patients showed a significant increase of vitamin B12 levels (P < 0.001) and a significant decrease in MMA levels (P < 0.001). Biochemical improvement occurs in both patients with and without clinical symptoms. The control group showed a significant increase of MMA levels (P < 0.001). To examine whether biochemical benefits of vitamin B12 supplementation are correlated with clinical improvement, patient records were checked for complaints. Complaints were disappeared after treatment, while no improvement was seen in untreated patients.
Conclusion: This study shows that all bariatric patients with vitamin B12 levels between 140 and 200 pmol/L benefit clinical and biochemical from vitamin B12 supplementation, regardless the MMA levels.
Keywords: Bariatric surgery; Deficiencies; Methylmalonic acid; Obesity; Vitamin B12.