Effect of Vitamin D Supplementation on Muscle Mass and Function

Phase 4

Completed

• Conditions: Obesity; Insulin Resistance; Inflammation
• Interventions: Dietary Supplement: Vitamin D; Drug: Placebo

• Registration Number: NCT01199926
• Lead Sponsor: Purdue University

Brief Summary

The study was designed to assess the effects of vitamin D supplementation during exercise training on body composition, muscle function, and glucose tolerance. The investigators hypothesis for these studies is that vitamin D supplementation enhances exercise-induced increases in strength and lean mass, potentially through enhancing insulin sensitivity and reducing inflammation.

Detailed Description

The study was designed to assess the effects of vitamin D supplementation during exercise training on body composition, muscle function, and glucose tolerance. It was a double-blind, randomized, placebo-controlled, clinical trial with participants randomized into either a 4,000 IU/day vitamin D or placebo group and all participants completed 12 wks (3 d/wk) of exercise training.

Study Timeline

• Study Start: 2008-08
• Primary Completion: 2009-07
• Study Completion: 2010-02
• Study First Submitted: 2010-09-09
• Study First Submitted QC: 2010-09-10
• Study First Posted: 2010-09-13
• Status Verified: 2015-04
• Results First Submitted: 2015-04-29
• Results First Submitted QC: 2015-04-29
• Last Update Submitted: 2015-04-29
• Results First Posted: 2015-05-15
• Last Update Posted: 2015-05-15

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 34

Inclusion Criteria

• Physical activity scores in the "low" to "very low" category
• Fitness estimations in the "below average" or lower categories
• body mass index scores >24.9 indicating overweight or obesity.

Exclusion Criteria

• Use of tanning booths or other artificial UV light exposure
• High baseline vitamin D and calcium intake
• Plans to visit sunny/warm destinations during the winter months/study period
• History or presence of metabolic disease, type 2 diabetes, eating disorders, gastrointestinal disorders, pregnancy or lactation
• Use of drugs to treat obesity (last 12 weeks)
• Use of over the counter anti-obesity agents (last 12 weeks)
• Recent initiation of an exercise program (last four weeks).

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Placebo	Placebo	Participants in this arm consumed a placebo (microcrystalline cellulose) daily for 12 weeks while participating in a resistance exercise training program.
Placebo	Vitamin D	Participants in this arm consumed a placebo (microcrystalline cellulose) daily for 12 weeks while participating in a resistance exercise training program.
Vitamin D	Vitamin D	Participants in this arm consumed a 4000 IU vitamin D supplement daily for 12 weeks while participating in a resistance exercise training program.

Primary Outcome Measures

Name	Time	Method
Muscle Function	three months	The primary endpoint is the change in lean mass (kilograms) after the three month resistance exercise intervention.
Glucose Tolerance	three months	The primary endpoint is the change in the area under the glucose curve following an oral glucose tolerance test prior to and after the three month intervention.
Inflammation	three months	The primary endpoint is the change in C reactive protein after the three month intervention

Trial Locations

Locations (1)

Wastl Human Performance Laboratory, Purdue University; 🇺🇸 West Lafayette, Indiana, United States