Publications & Reports

A randomised controlled trial of high dose vitamin D in recent-onset type 2 diabetes.

Elkassaby S, Harrison LC, Mazzitelli N, Wentworth JM, Colman PG, Spelman T, Fourlanos S
Walter & Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville 3052, VIC, Australia; Burnet Clinical Research Unit, Royal Melbourne Hospital, Parkville 3050, VIC, Australia.


AIMS: Vitamin D insufficiency has been associated with impaired pancreatic beta-cell function. We aimed to determine if high dose oral vitamin D3 (D) improves beta-cell function and glycaemia in type 2 diabetes. METHODS: Fifty adults with type 2 diabetes diagnosed less than 12 months, with normal baseline serum 25-OH D (25D), were randomised to 6000 IU D (n=26) or placebo (n=24) daily for 6 months. Beta-cell function was measured by glucagon-stimulated serum C-peptide (delta C-peptide [DCP], nmol/l). Secondary outcome measures were fasting plasma glucose (FPG), post-prandial blood glucose (PPG), HbA1c and insulin resistance (HOMA-IR). RESULTS: In the D group, median serum 25D (nmol/l) increased from 59 to 150 (3 months) and 128 (6 months) and median serum 1,25D (pmol/l) from 135 to 200 and 190. After 3 months, change in DCP from baseline in D (+0.04) and placebo (-0.08) was not different (P=0.112). However, change in FPG (mmol/l) was significantly lower in D (-0.40) compared to placebo (+0.1) (P=0.007), as was the change in PPG in D (-0.30) compared to placebo (+0.8) (P=0.005). Change in HbA1c (%) between D (-0.20) and placebo (-0.10) was not different (P=0.459). At 6 months, changes from baseline in DCP, FPG, PPG and HbA1c were not different between groups. CONCLUSION: Oral D3 supplementation in type 2 diabetes was associated with transient improvement in glycaemia, but without a measurable change in beta-cell function this effect is unlikely to be biologically significant. High dose D3 therefore appears to offer little or no therapeutic benefit in type 2 diabetes.


  • Journal: Diabetes Research and Clinical Practice
  • Published: 01/12/2014
  • Volume: 106
  • Issue: 3
  • Pagination: 576-582