Effect of Probiotics on Testosterone in Men

Study Overview
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Brief Summary
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This study evaluates the effect of L. reuteri ATCC PTA 6475 supplementation on testosterone in men.

Detailed Description
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The probiotic Lactobacillus reuteri ATCC PTA 6475 has been shown to modulate testosterone levels in mice. It is not known if these effects are seen in humans and this trial is intended to study this. The aim of this study is to investigate if L. reuteri ATCC PTA 6475 will effect blood testosterone levels in in healthy male subjects 50-65 years of age.

Official Title
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A Double-blind Randomized Clinical Study Investigating Lactobacillus Reuteri Supplementations Influence on Testosterone Levels in Healthy Men

Conditions
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Healthy

Intervention / Treatment
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* Dietary Supplement: Lactobacillus reuteri (L. reuteri)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Willing and able to give signed informed consent for participation in the study. Healthy males aged between 50-65 with no known underlying medical conditions Subjects who are capable of taking themselves to testing centre at 3 separate timepoints (Baseline, week 6 and week 12). Subjects who are available to give fasting blood samples before 10am on day of blood sample collection No history of androgen or testosterone supplementation within 6 months prior to study start. Subjects who have not been taking antibiotics or probiotic supplements 4 weeks prior to study start 8. Able and willing to comply with the restirictions defined for the study period Ability to understand and comply with the requirements of the study, as judged by the investigator physician Exclusion Criteria: Subjects who presently have or have had cardiovascular issues in the past 2 years. Subjects who have a Body Mass Index of < 18 or > 30 Known elevated Prostate Specific Antigen levels. History of prostate or testicular cancer. Nicotine abuse Alcohol abuse

Ages Eligible for Study
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Minimum Age: 50 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: L. reuteri Low Dose<br>L. reuteri will be delivered in a capsule at a low dose including Vitamin D3. Administration twice daily. | Dietary Supplement: Lactobacillus reuteri (L. reuteri)<br>* L.reuteri high or low dose with vitamin D3 compared to vitamin D3 only<br>|
| Active Comparator: L. reuteri High Dose<br>L. reuteri will be delivered in a capsule at a high dose including Vitamin D3. Administration twice daily. | Dietary Supplement: Lactobacillus reuteri (L. reuteri)<br>* L.reuteri high or low dose with vitamin D3 compared to vitamin D3 only<br>|
| Placebo Comparator: Placebo<br>The placebo product will be identical to the active product in taste and appearance and include Vitamin D3 but without the L. reuteri. Administration twice daily. | Dietary Supplement: Lactobacillus reuteri (L. reuteri)<br>* L.reuteri high or low dose with vitamin D3 compared to vitamin D3 only<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Concentration of total testosterone | Change in total testosterone concentration over time | Baseline, 6 weeks, 12 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Free testosterone index | Change in Free testosterone index (100x(Testosterone/SHBG) over time | Baseline, 6 weeks, 12 weeks | 
| Percentage of hematokrit | Change in Hematokrit over time | Baseline, 6 weeks, 12 weeks | 
| Number of adverse events | Adverse event from administration of first dose until 12 weeks | Continously 12 weeks |