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The Effect of Vitamin C on Growth Hormone Secretion

This study has been withdrawn prior to enrollment.
(Unable to obtain funding to initiate the study. No subjects were enrolled.)
Information provided by (Responsible Party):
Hideo Makimura, Massachusetts General Hospital Identifier:
First received: February 10, 2012
Last updated: December 11, 2013
Last verified: December 2013
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
Intervention Model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary Purpose: Treatment
Official Title: The Effect of Vitamin C on Growth Hormone Secretion

Resource links provided by NLM:

Further study details as provided by Hideo Makimura, Massachusetts General Hospital:

Primary Outcome Measures:
  • Change from Baseline in GH secretion at 4 weeks [ Time Frame: Change from Baseline to 4 weeks ]
    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.

Enrollment: 0
Study Start Date: December 2013
Study Completion Date: December 2013
Primary Completion Date: December 2013 (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


Ages Eligible for Study:   18 Years to 60 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

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.
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Please refer to this study by its identifier: NCT01537094

United States, Massachusetts
Massachusetts General Hospital
Boston, Massachusetts, United States, 02114
Sponsors and Collaborators
Massachusetts General Hospital
Principal Investigator: Hideo Makimura, MD, PhD Massachusetts General Hospital
  More Information

Responsible Party: Hideo Makimura, Assistant Professor of Medicine, Massachusetts General Hospital Identifier: NCT01537094     History of Changes
Other Study ID Numbers: 2011-P-002912
Study First Received: February 10, 2012
Last Updated: December 11, 2013

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

Additional relevant MeSH terms:
Ascorbic Acid
Growth Substances
Physiological Effects of Drugs
Hormones, Hormone Substitutes, and Hormone Antagonists
Molecular Mechanisms of Pharmacological Action
Protective Agents processed this record on September 21, 2017