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The Effect of Vitamin C on Growth Hormone Secretion

This study is not yet open for participant recruitment.
Verified March 2013 by Massachusetts General Hospital
Sponsor:
Information provided by (Responsible Party):
Hideo Makimura, Massachusetts General Hospital
ClinicalTrials.gov Identifier:
NCT01537094
First received: February 10, 2012
Last updated: March 5, 2013
Last verified: March 2013
History of Changes
  Purpose

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.


Condition Intervention Phase
Obese
Disorder of Vitamin C
Growth Hormone Secretion Abnormality
 Dietary Supplement: Placebo
Dietary Supplement: Vitamin C 250 mg once daily
Dietary Supplement: Vitamin C 1,000 mg once daily
 Phase 2

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Parallel Assignment
Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor)
Primary Purpose: Treatment
Official Title: The Effect of Vitamin C on Growth Hormone Secretion

Resource links provided by NLM:

MedlinePlus related topics: Obesity Vitamin C
U.S. FDA Resources

Further study details as provided by Massachusetts General Hospital:

Primary Outcome Measures:
  • Change from Baseline in GH secretion at 4 weeks [ Time Frame: Change from Baseline to 4 weeks ] [ Designated as safety issue: No ]
    GH secretion will be assessed by overnight frequent blood sampling to assess maximum GH, nadir GH, mean overnight GH, as well as parameters of pulsatile secretion.


Estimated Enrollment: 45
Study Start Date: September 2013
Estimated Study Completion Date: September 2016
Estimated Primary Completion Date: September 2016 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Active Comparator: Vitamin C low dose
vitamin C 250 mg oral once daily
 Dietary Supplement: Vitamin C 250 mg once daily
Active Comparator: Vitamin C high dose
vitamin C 1,000 mg oral once daily
 Dietary Supplement: Vitamin C 1,000 mg once daily
Placebo Comparator: Placebo
Placebo oral once daily
 Dietary Supplement: Placebo

  Eligibility

Ages Eligible for Study:   18 Years to 60 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No
Criteria

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.
  Contacts and Locations
Please refer to this study by its ClinicalTrials.gov identifier: NCT01537094

Contacts
Contact: Hideo Makimura, MD, PhD 617-726-8277 hmakimura@partners.org

Locations
United States, Massachusetts
Massachusetts General Hospital Not yet recruiting
Boston, Massachusetts, United States, 02114
Sponsors and Collaborators
Massachusetts General Hospital
Investigators
Principal Investigator: Hideo Makimura, MD, PhD Massachusetts General Hospital
  More Information

No publications provided

Responsible Party: Hideo Makimura, Assistant Professor of Medicine, Massachusetts General Hospital
ClinicalTrials.gov Identifier: NCT01537094     History of Changes
Other Study ID Numbers: 2011-P-002912
Study First Received: February 10, 2012
Last Updated: March 5, 2013
Health Authority: United States: Institutional Review Board

Keywords provided by Massachusetts General Hospital:
low vitamin c
reduced growth hormone secretion

Additional relevant MeSH terms:
Ascorbic Acid
Congenital Abnormalities
Dwarfism, Pituitary
Dwarfism
Bone Diseases, Developmental
Bone Diseases
Musculoskeletal Diseases
Bone Diseases, Endocrine
Hypopituitarism
Pituitary Diseases
Hypothalamic Diseases
Brain Diseases
Central Nervous System Diseases
 Nervous System Diseases
Endocrine System Diseases
Vitamins
Hormones
Antioxidants
Molecular Mechanisms of Pharmacological Action
Pharmacologic Actions
Protective Agents
Physiological Effects of Drugs
Micronutrients
Growth Substances
Hormones, Hormone Substitutes, and Hormone Antagonists

ClinicalTrials.gov processed this record on May 23, 2013