Endocrinology

Could Vitamin D Supplementation Improve Diabetes Outcomes?

Patients with type 2 diabetes and vitamin D deficiency did not benefit from vitamin D supplementation, according to a recent.

The randomized, placebo-controlled trial enrolled 62 men and women with type 2 diabetes and vitamin D deficiency. At baseline, participants were assigned to receive either a 400,000 IU oral vitamin D3 supplement or placebo. Those assigned to the vitamin D group continued to receive a 200,000 IU dose vitamin D3 supplement for an additional 4 weeks if their serum 25(OH)D level was below 100 nmol/L. All participants were followed for 6 months. Endogenous glucose production and first-phase insulin secretion were assessed as the primary end points.
_________________________________________________________________________________________________________________________________________________________
RELATED CONTENT
Study Questions Effectiveness of Vitamin D Supplementation for CVD Prevention
Probiotics, Prebiotics Benefit Glycemic Control
_________________________________________________________________________________________________________________________________________________________

Among participants assigned to the vitamin D group, the mean baseline serum 25(OH)D was 38.0 ± 12.6 nmol/L, which increased to 96.9 ± 18.3 nmol/L after 4 weeks. The mean serum 25(OH)D dropped to 73.2 ± 13.7 nmol/L after 3 months, and dropped again at 6 months to 53.7 ± 9.2 nmol/L.

Overall, the total exposure to vitamin D during the study was 1870 ± 192 per week in the vitamin D group and 1090 ± 377 nmol/L per week in the placebo group.

While treatment with vitamin D supplements showed increases in serum 25(OH)D levels, insulin sensitivity, endogenous glucose production, and glycemic control did not differ between the groups. Additionally, first-phase insulin secretion did not change significantly after treatment with vitamin D supplements.

“These findings do not support such use of therapeutic vitamin D3 supplementation to improve glucose homeostasis in patients with [type 2 diabetes],” the researchers concluded.

—Melissa Weiss

Reference:

Gulseth HL, Wium C, Angel K, Eriksen 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 June 21, 2017]. Diabetes Care. https://doi.org/10.2337/dc16-2302.