Supplementation With Vitamin D Improves Leptin Resistance

Study Overview
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Brief Summary
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Participants will be randomly assigned in one of two groups. Group A: oral supplementation with 4,000 IU of vitamin D (cholecalciferol). Group B: oral supplementation with 400 IU of vitamin D (cholecalciferol). Both treatments will be consumed daily for 6 months. Outcomes will be evaluated at baseline, three and six months. Variables related to leptin resistance will be evaluated. The main hypothesis is that vitamin D will diminish leptin resistance in overweight and obese women. If the hypothesis is confirmed, women will show a reduction in the Resting energy expenditure: serum Leptin ratio (REE: Leptin ratio), as well as a reduction of hunger, body weight, body and abdominal fat and an increase in resting energy expenditure.

Detailed Description
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Study subjects will get dietary advice and physical activity counseling. At the end of the study, participants with suboptimal vitamin D levels (<80 nmol/L 25-OH-D) will receive treatment to normalize their vitamin D status. Variables related to leptin resistance like resting metabolic expenditure, hunger, body weight and human body fat will be assessed. Outcomes will include, glucose, insulin, C-reactive protein, inflammatory interleukins (IL-6 & TNF-α) and non-inflammatory interleukins (IL-10 & TGF-β-1).

Official Title
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Effect of Vitamin D Supplementation on Leptin Resistance, Hunger, Body Weight and Resting Energy Expenditure in Obese Women.

Conditions
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Overweight, Obesity

Intervention / Treatment
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* Dietary Supplement: Cholecalciferol


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: BMI: 25-29.9 Serum vitamin D levels: 20-80 nmol/L (25-OH-D) Exclusion Criteria: Liver disease Kidney disease Diabetes mellitus Malignity Any kind of hormonal disorder Medication that modify hunger/satiety answer and those medications that alter -the glucose/insulin metabolism Subjects with diet treatment to lose weight

Ages Eligible for Study
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Minimum Age: 45 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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Female

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: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Cholecalciferol: 400 IU/day<br>Control: (n=50) Each subject will be evaluated after supplementation during six months with Vitamin D (Cholecalciferol: 400 IU/day) | Dietary Supplement: Cholecalciferol<br>* Cholecalciferol: 4,000 IU/day and 400 IU/day<br>* Other names: Cholecalciferol supplementation (400 IU and 4000 IU);|
| Experimental: Cholecalciferol 4000 IU/day<br>Experimental: (n=50) Each subject will be evaluated after supplementation during six months with Vitamin D | Dietary Supplement: Cholecalciferol<br>* Cholecalciferol: 4,000 IU/day and 400 IU/day<br>* Other names: Cholecalciferol supplementation (400 IU and 4000 IU);|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Evaluation of leptin resistance: (resting energy expenditure: leptin ratio) before and after (3 and 6 months) supplementation with vitamin D3 (cholecalciferol) 4,000 or 400 IU/day. |  | basal, third and sixth month | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Effect of vitamin D supplementation (25-OH-D): hunger, body weight, energy intake, resting energy expenditure, and body fat, improvement on low intensity chronic inflammation, SOCS-3 expression and JAK2/STAT3 signal. |  | Basal, third and sixth month |