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The Effect of Vitamin C on Growth Hormone Secretion

NCT ID: NCT01537094

Last Updated: 2013-12-13

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

WITHDRAWN

Clinical Phase

PHASE2

Study Classification

INTERVENTIONAL

Study Start Date

2013-12-31

Study Completion Date

2013-12-31

Brief Summary

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Obesity is associated with reduced growth hormone (GH) secretion. GH secretion is regulated by nutritional stimuli including fasting, insulin, glucose and free fatty acids. However, the role of micronutrients, such as vitamins, on GH secretion has not been investigated in much detail. Vitamin C levels are also reduced in obesity, and the investigators recently demonstrated a possible role for dietary vitamin C intake in the regulation of GH secretion in two preliminary retrospective studies. The investigators therefore propose a more detailed prospective physiological study to examine the effects of increasing dietary vitamin C intake on GH secretion in a physiologic, intervention study. The investigators hypothesize that increasing vitamin C concentrations in obese subjects with sub-optimal plasma vitamin C levels and reduced GH secretion will increase GH secretion.

Detailed Description

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Conditions

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Obese Disorder of Vitamin C Growth Hormone Secretion Abnormality

Keywords

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low vitamin c reduced growth hormone secretion

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

PARALLEL

Primary Study Purpose

TREATMENT

Blinding Strategy

QUADRUPLE

Participants Caregivers Investigators Outcome Assessors

Study Groups

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Vitamin C low dose

vitamin C 250 mg oral once daily

Group Type ACTIVE_COMPARATOR

Vitamin C 250 mg once daily

Intervention Type DIETARY_SUPPLEMENT

Vitamin C high dose

vitamin C 1,000 mg oral once daily

Group Type ACTIVE_COMPARATOR

Vitamin C 1,000 mg once daily

Intervention Type DIETARY_SUPPLEMENT

Placebo

Placebo oral once daily

Group Type PLACEBO_COMPARATOR

Placebo

Intervention Type DIETARY_SUPPLEMENT

Interventions

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Placebo

Intervention Type DIETARY_SUPPLEMENT

Vitamin C 250 mg once daily

Intervention Type DIETARY_SUPPLEMENT

Vitamin C 1,000 mg once daily

Intervention Type DIETARY_SUPPLEMENT

Eligibility Criteria

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Inclusion Criteria

1. Men and women age 18-60
2. BMI ≥ 30 kg/m2
3. Waist circumference ≥ 102 cm in men and ≥ 88 cm in women
4. Plasma vitamin C concentration ≤ 23 µmol/l
5. Peak stimulated GH ≤ 4.2 µg/l upon GHRH-arginine stimulation test

Exclusion Criteria

1. History of hypopituitarism, pituitary surgery, pituitary/brain radiation, recent traumatic brain injury or any other condition known to affect the GH axis.
2. History of severe chronic illness including anemia, chronic kidney disease, liver disease, oxygen dependent COPD or HIV
3. Subjects on testosterone, glucocorticoids, anabolic steroids, GHRH, GH or IGF-1 within 3 months of enrollment
4. Use of dietary supplements including vitamin C or once daily multi-vitamins
5. Subjects with Hgb \< 912 g/dL, SGOT \> 2.5x upper limit of normal or Creatinine \> 1.5 mg/dL
6. Subjects with poorly controlled diabetes, defined as HbA1c \> 8%.
7. Changes in lipid lowering or anti-hypertensive regimen within 3months of screening
8. Subject is currently enrolled in another investigational device or drug trial(s), or subject has received other investigational agent(s) within 28 days of baseline visit
9. Any condition judged by the patient's physician to cause this clinical trial to be detrimental to the patient.
Minimum Eligible Age

18 Years

Maximum Eligible Age

60 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

No

Sponsors

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Massachusetts General Hospital

OTHER

Sponsor Role lead

Responsible Party

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Hideo Makimura

Assistant Professor of Medicine

Responsibility Role PRINCIPAL_INVESTIGATOR

Principal Investigators

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Hideo Makimura, MD, PhD

Role: PRINCIPAL_INVESTIGATOR

Massachusetts General Hospital

Locations

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Massachusetts General Hospital

Boston, Massachusetts, United States

Site Status

Countries

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United States

Other Identifiers

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2011-P-002912

Identifier Type: -

Identifier Source: org_study_id