A double-blind, randomized, placebo-controlled trial of the short-term effect of vitamin D3 supplementation on insulin sensitivity in apparently healthy, middle-aged, centrally obese men

Diabet Med. 2009 Jan;26(1):19-27. doi: 10.1111/j.1464-5491.2008.02636.x.


Aim: To determine the short-term effect of vitamin D(3) supplementation on insulin sensitivity in apparently healthy, middle-aged, centrally obese men.

Subjects and methods: A double-blind randomized controlled trial was conducted at a tertiary care facility in which 100 male volunteers aged > or = 35 years received three doses of vitamin D(3) (120,000 IU each; supplemented group) fortnightly or placebo (control group). Hepatic fasting insulin sensitivity [homeostasis model assessment (HOMA), quantitative insulin-sensitivity check index, HOMA-2], postprandial insulin sensitivity [oral glucose insulin sensitivity (OGIS)], insulin secretion (HOMA%B, HOMA2-%B), lipid profile and blood pressure were measured at baseline and at 6 weeks' follow-up.

Results: Seventy-one of the recruited subjects completed the study (35 in supplemented group, 36 in control group). There was an increase in OGIS with supplementation by per protocol analysis (P = 0.038; intention-to-treat analysis P = 0.055). The age- and baseline 25-hydroxyvitamin D level-adjusted difference in change in OGIS was highly significant (mean difference 41.1 +/- 15.5; P = 0.01). No changes in secondary outcome measures (insulin secretion, basal indices of insulin sensitivity, blood pressure or lipid profile) were found with supplementation.

Conclusion: The trial indicates that vitamin D(3) supplementation improves postprandial insulin sensitivity (OGIS) in apparently healthy men likely to have insulin resistance (centrally obese but non-diabetic).

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abdominal Fat
  • Adult
  • Blood Glucose / drug effects*
  • Body Fat Distribution
  • Cholecalciferol / therapeutic use*
  • Double-Blind Method
  • Humans
  • India
  • Insulin / blood
  • Insulin / metabolism*
  • Insulin Resistance / physiology*
  • Male
  • Middle Aged
  • Obesity / drug therapy*
  • Statistics as Topic
  • Waist-Hip Ratio


  • Blood Glucose
  • Insulin
  • Cholecalciferol