Calcium and vitamin D can improve the metabolic profile of women with gestational diabetes mellitus, according to investigators in Iran who found significant reductions in fasting glucose, serum insulin levels, and low-density lipoprotein cholesterol associated with combined use of the supplements.
For their research, published June 23 in Diabetologia (doi:10.1007/s00125-014-3293-x), Zatollah Asemi, Ph.D., of Kashan (Iran) University and colleagues, randomized 56 women diagnosed with gestational diabetes mellitus (GDM) at between 24 and 28 weeks’ gestation to 1,000 mg calcium daily and to a 50,000 IU pearl of vitamin D3 at baseline and day 21 or placebo. Women and providers were blinded to treatment assignment.
At 6 weeks, compared with placebo, women assigned to the calcium-vitamin D group (n = 28) saw significantly lower fasting glucose (-0.89 ± 0.69 vs. +0.26 ± 0.92 mmol/L), serum insulin levels (-13.55 ± 35.25 vs. +9.17 ± 38.50 pmol/L) and homeostatic model assessment insulin resistance (-0.91 ± 1.18 vs + 0.63 ± 2.01).
They also saw a significant reduction in LDL cholesterol (-0.23 ± 0.79 vs. +0.26 ± 0.74 mmol/L). The treatment group saw increases in plasma glutathione, and supplementation was seen to prevent a rise in plasma malondialdehyde levels.
C-reactive protein and total antioxidant capacity were not affected by calcium and Vitamin D supplementation in this study, researchers wrote.
Dr. Asemi and colleagues, who have previously studied vitamin D supplementation in women with GDM and found it associated with improved insulin function and decreased total and LDL cholesterol (Am. J. Clin. Nutr. 2013;98:1425-32), hypothesized that calcium and vitamin D together would be more efficient in influencing metabolic profiles, possibly through their combined effects on cell cycle regulation, activation of antioxidant enzymes, and suppression of parathyroid hormone.
"GDM is associated with insulin resistance, increased inflammatory factors, and oxidative stress. Elevated circulating levels of inflammatory markers and impaired insulin metabolism in GDM can predict the progression to type 2 diabetes later in life and neonatal complications," investigators explained.
The researchers noted as weaknesses of their study that it did not capture pregnancy outcomes or certain biomarkers of inflammation and oxidative stress and that two subjects in the placebo group and three in the treatment group were lost to follow-up. The study was funded by Kashan University. None of the researchers disclosed conflicts of interest.