Effects of vitamin D-fortified low fat yogurt on glycemic status, anthropometric indexes, inflammation, and bone turnover in diabetic postmenopausal women: A randomised controlled clinical trial

Summary Background & aims Low levels of serum 25-hydroxy vitamin D (25(OH)D) are common in type 2 diabetic patients and cause several complications particularly, in postmenopausal women due to their senile and physiological conditions. This study aimed to assess the effects of vitamin D-fortified low fat yogurt on glycemic status, anthropometric indexes, inflammation, and bone turnover in diabetic postmenopausal women. Methods In a randomized, placebo-controlled, double-blind parallel-group clinical trial, 59 postmenopausal women with type 2 diabetes received fortified yogurt (FY; 2000 IU vitamin D in 100 g/day) or plain yogurt (PY) for 12 weeks. Glycemic markers, anthropometric indexes, inflammatory, and bone turnover markers were assessed at baseline and after 12 weeks. Results After intervention, in FY group (vs PY group), were observed: significant increase in serum 25(OH)D and decrease of PTH (stable values in PY); significant improvement in serum fasting insulin, HOMA-IR, HOMA-B, QUICKI, and no changes in serum fasting glucose and HbA1c (significant worsening of all indexes in PY); significant improvement in WC, WHR, FM, and no change in weight and BMI (stable values in PY); significant increase of omentin (stable in PY) and decrease of sNTX (significant increase in PY). Final values of glycemic markers (except HbA1c ), omentin, and bone turnover markers significantly improved in FY group compared to PY group. Regarding final values of serum 25(OH)D in FY group, subjects were classified in insufficient and sufficient categories. Glycemic status improved more significantly in the insufficient rather than sufficient category; whereas the other parameters had more amelioration in the sufficient category. Conclusions Daily consumption of 2000 IU vitamin D-fortified yogurt for 12 weeks improved glycemic markers (except HbA1c ), anthropometric indexes, inflammation, and bone turnover markers in postmenopausal women with type 2 diabetes. Trial registration www.irct.ir (IRCT2013110515294N1).