Vitamin D-fortified milk did not affect glycemic control, lipid profile, and anthropometric measures in patients with type 2 diabetes, a triple-blind randomized clinical trial.

Background/objectives: The effect of vitamin D on glycemic status of diabetes patients is controversial. The objective was to assess the effect of vitamin D-fortified milk on cardiometabolic markers of patients with type 2 diabetes.

Subjects/methods: In this randomized triple-blind, placebo-controlled trial, 102 patients (34 males and 68 females) aged 31-74 years with type 2 diabetes were randomized to receive either 250 ml unfortified or 250 ml 1000 IU vitamin D-fortified milk daily for 9 weeks. Anthropometric characteristics, blood pressure, and serum levels of glucose, insulin, and lipids were determined at baseline and after 9 weeks.

Results: Serum 25-hydroxy vitamin D concentrations improved in the fortified milk group compared to the control group (+14 ± 20 vs. +4 ± 17 ng/ml; P = 0.001). Both groups showed significant increases in serum calcium (P < 0.01) and decreases in total cholesterol, waist and hip circumference, and systolic and diastolic blood pressure (P < 0.001). Also, there was a significant reduction in body mass index of fortified milk group (P < 0.001). None of these changes were statistically significant between the two groups. Glycosylated hemoglobin (HbA1c) significantly decreased in both groups with a more remarkable reduction in the plain milk consumers, making a significant between-group difference (7.5% compared to 3.1%; P = 0.01).

Conclusions: Overall, daily consumption of one cup of milk containing 1000 IU vitamin D for 9 weeks substantially improved vitamin D deficiency in patients with type 2 diabetes but it did not affect cardiometabolic parameters over that of plain milk.