Taking vitamin D supplements did not improve glycemic control or blood pressure among patients with impaired fasting glucose (IFG) or impaired glucose tolerance (IGT) in a recent study published in the August 2014 issue of Diabetes Care.
A total of 511 patients with IFG and IGT were randomly assigned to receive either 20,000 IU of vitamin D3 supplements each week or placebo.
At baseline, low serum 25-hydroxyvitamin D levels were 59.9 nmol/L among supplement patients and 61.1 nmol/L among placebo groups. After 1 year, vitamin D levels increased by 45.8 nmol/L in supplement patients and 3.4 nmol/L in the placebo group. At that time, measurements of glucose metabolism, insulin secretion or sensitivity, blood pressure, and high sensitivity to C-reactive protein did not differ significantly. Total and low-density lipoprotein cholesterol levels did significantly decrease among those taking vitamin D supplements compared with the placebo group. High-density lipoprotein (HDL) cholesterol, however, also decreased, and the change in the total-to-HDL cholesterol ratio did not differ significantly.
“This study shows that vitamin D supplementation does not improve glycemic indices, blood pressure, or lipid status in subjects with IFG and/or IGT,” the authors of the study concluded.