Supplementation of vitamin D and calcium may reduce fasting plasma glucose and insulin, improve insulin sensitivity and reduce low-density lipoprotein 'bad' cholesterol while boosting 'good' cholesterol for women with Gestational Diabetes Mellitus (GDM), according to Iranian researchers.
The research published in Diabetologia – the journal of the European Association for the Study of Diabetes – looked at the influence of such supplementation on women with GDM. GDM is a condition whereby women with no previous history of diabetes develop high blood glucose levels during pregnancy and is characterised by carbohydrate intolerance and metabolic disorders.
The complication in pregnancy affects around 7% of pregnant women in the US, but has a global prevalence range of 1-14%, depending on the country. GDM can increase the risk of pre-eclampsia , pre-term delivery and delivery by caesarean section, the researchers said.
The study, led by Dr Ahmad Esmaillzadeh of the Isfahan University of Medical Sciences in Iran, said the findings that calcium and vitamin D supplementation in GDM women had beneficial effects on metabolic profile were important because elevated circulating levels of inflammatory markers and impaired insulin metabolism in GDM could predict the progression to type 2 diabetes (T2D) for the mothers later in life as well as “complications” for the newborns.
“Impaired insulin metabolism in women with GDM can result in adverse long term maternal outcomes and increased perinatal morbidity (babies large for gestational age, birth trauma, pre-eclampsia), and long-term consequences in the offspring. In addition, increased inflammatory markers in GDM might predict the future development of both metabolic and cardiovascular disease," they wrote.
The researchers said this was the first study to look at the joint effects of calcium–vitamin D supplementation on insulin function, lipid profiles, inflammatory factors and biomarkers of oxidative stress for women with GDM.
The trial involved 56 women aged 18-40 at 24–28 weeks’ gestation, all with GDM. The participants were randomly assigned to receive either a combination of calcium and vitamin D supplements or placebos. The experiment group was given 1000 mg of calcium per day and 50000 international units of vitamin D3 tablets, taken once at the beginning and once after 21 days of study. The placebo group received their tablets at the same intervals.
Fasting blood samples were taken at study baseline and after six weeks of intervention.
"In this study, calcium plus vitamin D supplementation of pregnant women with GDM resulted in improved glycaemic status, a significant decrease in serum LDL-cholesterol, a significant rise in HDL-cholesterol and plasma GSH [total glutathione], and a significant difference in plasma MDA [Malondialdehyde] levels, but did not affect other lipid profiles, inflammatory factors or plasma TAC [Total Antioxidant Capacity]," the researchers wrote.
Published online ahead of print, DOI 10.1007/s00125-014-3293-x
“Effects of calcium–vitamin D co-supplementation on glycaemic control, inflammation and oxidative stress in gestational diabetes: A randomised placebo-controlled trial”
Authors: Z. Asemi, M. Karamali and A. Esmaillzadeh