Female Hormone Profile
Conditions
Brief summary
Participation will take place over two visits to the Clinical Exercise Research Center (CERC) at the University of Southern California Health Sciences Campus. On the first visit, height, weight, and body composition by bioelectrical impedance are recorded. Questionnaires and withdrawal of a sample of blood (1 tablespoon) are also completed. The intervention begins the day following the first visit. The intervention protocol consists of three weeks of consuming either a placebo capsule or a 5000 IU Vitamin D capsule daily and completing a daily survey. The second visit to CERC immediately follows the 3-weeks intervention. In this visit, the same blood sampling protocol will be completed. The assignment of the intervention will be randomized (i.e., rolling a die), and participants are blinded to group assignment.
Detailed description
High-dose Vitamin D supplementation significantly increases testosterone in men, but research about Vitamin D's effect on testosterone in young, healthy females is limited \[1\]. However, testosterone is a critical hormone for many physiologic functions in females including maintenance of reproductive health, cognitive function, body composition, mental health, bone density, muscle strength, and much more. Thus, this study aims to investigate the effect of Vitamin D supplementation on testosterone and gonadotropin concentrations in premenopausal, healthy females. The study investigators hypothesize that Vitamin D supplementation will result in a significant increase in circulating Vitamin D \[25(OH)D\], testosterone, and sex hormone modulators (i.e., gonadotropins and SHBG) concentrations in pre-menopausal females and that the magnitude of testosterone increase will be inversely related to fat mass and BMI. 20 young, healthy females will be randomized to either a treatment or placebo group for a three-week intervention, where the control group will take 5000 IU of Vitamin D orally, daily and the placebo group will take a placebo capsule orally, daily. Circulating Vitamin D, testosterone, gonadotropin, and SHBG concentrations will be assessed via serum pre- and post-intervention. Two-tailed unpaired t-test will be conducted to assess the relative change in total testosterone and free testosterone levels between the groups. Additionally, correlation analyses will be performed for correlations between body composition metrics and 25(OH)D, testosterone, and sex hormone modulator concentrations.
Interventions
DIETARY_SUPPLEMENTVitamin D (Cholecalciferol )
5000 IU Vitamin D (as cholecalciferol) capsules (Vitamin D3 125 mcg \[5,000 IU\], Pure Encapsulation, LLC) daily
DIETARY_SUPPLEMENTPlacebo Group
One placebo capsule (Zeebo Imagine, Zeebo) daily.
Sponsors
University of Southern California
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
HEALTH_SERVICES_RESEARCH
Masking
SINGLE (Subject)
Masking description
Single blinded intervention. Those measuring the blood samples' hormonal will also be blinded to the intervention group but will not have a role in data analysis.
Intervention model description
Participants will be randomized to either a treatment or control group upon enrollment and blinded to group assignment. The treatment intervention will consist of three weeks of one 5000 IU cholecalciferol capsule (Pure Encapsulations, LLC) daily, with breakfast. The control group will also take a daily, with breakfast, placebo capsule (Zeebo) for the three-week intervention.
Eligibility
Sex/Gender
FEMALE
Age
18 Years to 35 Years
Healthy volunteers
Yes
Inclusion criteria
* Assigned female at birth * 18 to 35 years of age * No chronic diseases affecting the uptake of Vitamin D or causing Vitamin D sensitivity (e.g., sarcoidosis, tuberculosis, Wegener's granulomatosis, other forms of vasculitis, inflammatory bowel diseases, etc.) \[21\] * Completion and signature of the informed consent document * Non-pregnant or trying to become pregnant * No supplementation with Vitamin D within three months of enrollment * No documented gynecological disease (e.g., PCOS, endometriosis, etc.) * Weight greater than or equal to 110 lbs
Exclusion criteria
* Pregnant * Supplementation with Vitamin D within three months of enrollment * Taking exogenous hormones * Documented gynecological disease (e.g., PCOS, endometriosis, etc.) * Suffering from chronic diseases affecting the uptake of Vitamin D or causing Vitamin D sensitivity (e.g., sarcoidosis, tuberculosis, Wegener's granulomatosis, other forms of vasculitis, inflammatory bowel diseases, etc.) \[21\] * Weight less than 110 lbs
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Hormonal Effects of Vitamin D in Young, Healthy Women | 3 weeks | The primary objective is to evaluate the effect of acute Vitamin D supplementation on systemic Vitamin D, testosterone, and sex hormone modulators in pre-menopausal, healthy females. Circulating testosterone (total testosterone and free testosterone) concentrations (ng/dL) will be assessed via serum pre- and post-Vitamin D intervention. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Effects of Body Composition on Hormonal Changes Due to Vitamin D Supplementation in Young, Healthy Women | 3 weeks | Secondary analyses will evaluate the effect of body composition on change in testosterone concentration due to acute Vitamin D supplementation of pre-menopausal, healthy females. Testosterone (TT and FT) concentrations will be correlated with body composition metrics, i.e. fat and fat-free mass (kg), pre- and post-Vitamin D intervention. |
Countries
United States
Contacts
PRINCIPAL_INVESTIGATORGiuliet L Kibler
University of Southern California - Division of Biokinesiology and Physical Therapy
Outcome results
None listed