HealthDay News — For patients with type 2 diabetes and vitamin D deficiency, vitamin D supplementation has no impact on insulin sensitivity or secretion, according to a study published online in Diabetes Care.
Hanne L. Gulseth, MD, PhD, from Oslo University Hospital in Norway, and colleagues examined the impact of vitamin D supplementation on insulin sensitivity and insulin secretion in 62 adults with type 2 diabetes and vitamin D deficiency. Participants received a single dose of 400,000 IU oral vitamin D3 or placebo; if serum 25-hydroxyvitamin D (25[OH]D) was <100 nmol/L after 4 weeks, the vitamin D group received an additional 200,000 IU D3.
The researchers found that the mean serum 25(OH)D was 38±12.6 nmol/L at baseline and increased to 96.9±18.3 nmol/L, 73.2±13.7 nmol/L, and 53.7±9.2 nmol/L after 4 weeks, 3 months, and 6 months, respectively. During 6 months, the total exposure to 25(OH)D was 1,870±192 nmol/L per week in the vitamin D group and 1,090±377 nmol/L per week in the placebo group (P <.001). After treatment, there was no difference between or within the groups in insulin sensitivity, endogenous glucose production, or glycemic control (P =.52). There was no significant change after treatment in first-phase insulin secretion (P =.10).
“These findings do not support such use of therapeutic vitamin D3 supplementation to improve glucose homeostasis in patients with type 2 diabetes,” the authors write.
Gulseth HL, Wium C, Angel K, Erikseon EF, Birkeland KI. Effects of vitamin D supplementation on insulin sensitivity and insulin secretion in subjects with type 2 diabetes and vitamin D deficiency: a randomized controlled trial [published online May 3, 2017]. Diabetes Care. doi:10.2337/dc16-2302