Plasma pyridoxal phosphate as indicator of vitamin B6 status in morbidly obese women after gastric restriction surgery.

Plasma pyridoxal phosphate (PLP) concentrations were determined in 15 morbidly obese women before and after gastric restriction surgery for weight reduction. The subjects received a daily vitamin-mineral supplement containing 2 or 3 mg of vitamin B6 for 9 days before the operation and either a placebo or a multivitamin supplement containing 0.4, 0.8 or 2 mg of vitamin B6 for 3 months postoperatively. During the fourth month, all subjects received 2 mg of supplemental vitamin B6 per day. Dietary intakes of the vitamin were calculated from 3-day intake records kept by the subjects. Blood samples for PLP determination were obtained preoperatively and twice between weeks 4 and 8 and at 3 and 4 months postoperatively. The mean concentration of plasma PLP increased significantly from preoperation to 4 to 5 weeks postoperation and returned to the preoperative level by 6 to 8 weeks, with no further changes during the rest of the experimental period. There was no correlation between plasma PLP and either total or supplemental intakes of vitamin B6 at any of the time periods studied. Significant positive correlations were found between the preoperative and the first two postoperative plasma PLP levels (r = 0.93 and 0.67, p less than 0.001 and 0.005, respectively) and between the rate of weight loss and plasma PLP at 4-5 weeks and at 4 months postoperatively. Muscle PLP reserve may be mobilized during the early postoperative period and complicate the use of plasma PLP as a measure of vitamin B6 status.

RCT Entities:   Population Interventions Outcomes