Effects of Vitamin D on Skeletal Muscle Strength in Resistance Trained Adult Females

August 8, 2022 updated by: Nilophar Zandieh, MS, Auburn University
The majority of vitamin D research has been done in non-athletic populations, particularly older populations, to analyze muscle weakness, pain, balance, and fractures. It has been reported that over a billion people worldwide are vitamin D deficient, including 36-70% of the young adult population. Previous literature also suggests that, even among healthy athletes, over 50% of subjects sampled had inadequate or insufficient vitamin D levels. Vitamin D deficiency can occur in young women, including pregnant women, and the risk of deficiency is even higher with advancing age in a woman's lifecycle. It is known that preserving skeletal muscle (SM) function is critical for women of all ages to prevent sarcopenia. Two factors in preserving SM are protein intake and resistance training. Relatively unknown are the actions of Vitamin D on SM function. Vitamin D deficiency can have a negative effect on SM function . However, additional research is needed to investigate the increase in SM strength when the serum concentration of vitamin D is improved. It is possible that an athlete may require an increased intake of vitamin D to assure adequate availability and storage for optimal performance; however, is known that food sources of vitamin D are limited in sufficient quantity to meet these requirements. Athletes who are insufficient will require a supplement of vitamin D3 for up to 5000 IU/day for at least eight weeks, to potentially reach optimal levels, then 1000-2000 IU/day for maintenance.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

The investigators seek to determine if women with a vitamin D serum concentration lower than 50 nmol/L and who regularly resistance train will improve strength performance outcomes when taking a daily supplement of 5000 IU of vitamin D3 over an 8-week period, as compared to the same demographic of women who do not take a daily supplement of vitamin D3. The participants will receive "Nature's Bounty Vitamin D3, 5,000 IU, soft gels" and the PI will be providing the supplement and the placebo. A pre-intervention data collection and screening (PRE) will be performed involving blood draw, food log, a body composition test (using Dual-energy X-ray absorptiometry [DEXA]), and a BioDex testing to determine maximal muscle strength. Following PRE testing, the participants will be divided into one of two groups: 1) taking a vitamin D3 supplement (n=20) or, 2) taking a placebo. The participants will be instructed to continue their resistance training regimen. Training will be logged and turned in to the PI weekly. The participants will perform a post-intervention data collection (POST), which includes the same test from PRE. Variables of interest will include changes in: 1) blood level of vitamin D, 2) muscle and fat mass, and 3) leg strength/power during the BioDex test.

Study Type

Interventional

Enrollment (Anticipated)

40

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

19 years to 55 years (Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

Female

Description

Inclusion criteria will include:

Participant will need to answer "yes" to the following items:

  1. female
  2. not pregnant
  3. between the ages of 19-55 years old
  4. a non-smoker
  5. currently resistance training (i.e., lifting weights) for more than 2 days/week for a minimum of > 24 months
  6. free of any known overt cardiovascular or metabolic disease
  7. not an active user of tanning beds
  8. not consuming now or haven't consumed within the last 6 months, a vitamin D or multivitamin supplement or a form of a supplement with vitamin D added
  9. not consuming now or haven't consumed within the last 2 months, agents that affect hormones (testosterone boosters, growth hormone boosters, etc.) (does not include birth control/oral contraceptives)
  10. not allergic to rubbing alcohol

Exclusion criteria will include:

1) Outside of study inclusion parameters

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Treatment Group
Participants in this group will be administered an oral Vitamin D3 supplement; 5,000 IU/ day. The participants will take the supplement themselves, orally, once per day, for 8 weeks.
Dietary supplement: Nature Made Vitamin D3 5,000 IU, 125mcg
Taking a 5,000 IU oral supplement of Vitamin D3, daily, for 8 weeks, may improve strength performance in women who have and are continuing a resistance trained workout regimen. After blood vitamin D levels have been raised to an optimal range, a lower dosage may be assigned as needed from 5,000 IU per day to 1,000-2,000 IU per day.
Other Names:
  • Spring Valley
  • Life Extensions
  • GNC
  • Nature's Bounty
  • CVSHealth
  • Swanson
Placebo Comparator: Control Group
Participants in this group will be administered an oral, soft-gel, lookalike placebo. The participants will take the supplement themselves, orally, once per day, for 8 weeks.
Dietary supplement: Placebo
Resistance trained women may not improve their strength performance with low levels of vitamin D in the blood.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Biodex Strength performance change
Time Frame: 8 weeks
Taking a daily supplement of 5,000 IU of vitamin D3 may change strength outcomes measured in newton meters (Nm).
8 weeks

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Serum 25(OH)D status
Time Frame: 8 weeks
Taking a daily supplement of 5,000 IU of vitamin D3 may change blood levels of vitamin D.
8 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Auburn University

Investigators

  • Study Chair: Donna O Burnett, PhD, Auburn University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Anticipated)

September 1, 2022

Primary Completion (Anticipated)

November 30, 2022

Study Completion (Anticipated)

February 1, 2023

Study Registration Dates

First Submitted

August 3, 2022

First Submitted That Met QC Criteria

August 3, 2022

First Posted (Actual)

August 5, 2022

Study Record Updates

Last Update Posted (Actual)

August 10, 2022

Last Update Submitted That Met QC Criteria

August 8, 2022

Last Verified

August 1, 2022

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 22-306

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

No

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

Yes

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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