From Ojo O et al. The effect of vitamin D supplementation in women with gestational diabetes mellitus. A systemic review and meta-analysis of randomised controlled trials. Int J Environ Res Public Health. 2019:16(10)
A meta-analysis has indicated that various factors relevant to improved blood sugar control are likely to be improved by vitamin D supplementation in a total of 173 women with gestational diabetes.
Fasting blood glucose decreased by a mean of 0.46 mmol/L
Glycated haemoglobin decreased by a mean of 0.37%
Serum insulin reduced by a mean of 4.10 uIU/mL.
My comment: Although the improvements are small, vitamin D supplements are inexpensive, easy to take and do not have the side effects of other medications.