High-dose thiamine supplementation improves glucose tolerance in hyperglycemic individuals: a randomized, double-blind cross-over trial

Abstract

To assess the effect of high-dose oral thiamine supplements on glucose tolerance in patients with impaired glucose metabolism. Twelve hyperglycemic subjects (10 cases of impaired glucose tolerance and 2 new cases of type 2 diabetes) completed this randomized, double-blind trial, where all participants received both placebo and thiamine capsules (3×100mg/day) for 6weeks in a cross-over manner. The main endpoint was changes in 2-h plasma glucose. Fasting plasma glucose and insulin, 2-h plasma insulin, the hemostatic model assessment of insulin resistance (HOMA-IR), renal function measurement and thiamin status were also evaluated at the commencement and completion of each treatment period. Thiamine supplementation resulted in significant decrease in 2-h plasma glucose relative to baseline (8.78±2.20 vs. 9.89±2.50mmol/l, p=0.004), with no significant change in the placebo arm. Fasting plasma glucose and insulin, and HOMA-IR increased significantly from baseline after 6weeks in the placebo arm (p=0.003, p=0.04 and p=0.02, respectively). These variables did not change with thiamine supplementation. There were no significant changes in 2-h plasma insulin or renal function marker, within or between arms. Supplementation with high-dose thiamine may prevent deterioration in fasting glucose and insulin, andimprove glucose tolerance in patients with hyperglycemia. High-dose thiamine supplementation may prevent or slow the progression of hyperglycemia toward diabetes mellitus in individuals with impaired glucose regulation.