Effectiveness of B vitamin supplementation following bariatric surgery: rapid increases of serum vitamin B12.

BACKGROUND: Few prospective studies have compared changes of nutrient intake while assessing effectiveness of thiamin, vitamin B12, and folate supplementation to prevent B vitamin deficiencies immediately following Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG). Therefore, we determined the response to 3 months supplementation on maintaining blood B vitamin concentrations.

METHODS: Women undergoing RYGB (n = 11) and SG (n = 11) consumed bariatric vitamin supplements (12 mg thiamin, 350 μg vitamin B12, 800 μg folic acid) daily for 3 months. Height, weight, body mass index, and blood vitamin concentrations were measured preoperatively and at 3 months. Wilcoxon signed-rank analyses compared body weight parameters, laboratory indices, and nutrient intake at baseline and 3 months.

RESULTS: Supplementation for 3 months maintained blood thiamin, increased serum folate from 13.1 ± 5.4 to 16.3 ± 6.0 nmol/L (P = 0.049), and increased serum vitamin B12 concentrations from 498 ± 150 to 736 ± 340 pg/mL (P = 0.005). Dietary intake of thiamin and folate decreased in the combined surgical groups, while dietary intake of B12 was maintained. Bariatric B vitamin supplements provided multiple intakes of the Recommended Dietary Allowances (1090% thiamin, 14,583% vitamin B12, 200% folate).

CONCLUSIONS: Although energy intake decreased 64%, B vitamin supplementation for 3 months resulted in a 48% increase of serum vitamin B12, a modest increase of serum folate, and no reduction of blood thiamin concentrations. Long-term effects of the rapid rise of serum B12 levels attributed to the high content of supplements warrant further investigation.