The Effect of Vitamin C on Growth Hormone Secretion

Study Description

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Brief Summary:

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 or disease	Intervention/treatment	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 Design

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Study Description Study Design Arms and Interventions Outcome Measures Eligibility Criteria Contacts and Locations More Information

Study Type :	Interventional (Clinical Trial)
Actual Enrollment :	0 participants
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
Study Start Date :	December 2013
Actual Primary Completion Date :	December 2013
Actual Study Completion Date :	December 2013

Arms and Interventions

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Study Description Study Design Arms and Interventions Outcome Measures Eligibility Criteria Contacts and Locations More Information

Arm	Intervention/treatment
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

Outcome Measures

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Primary Outcome Measures :

1. 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.

Eligibility Criteria

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Ages Eligible for Study:	18 Years to 60 Years (Adult)
Sexes Eligible for Study:	All
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

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Study Description Study Design Arms and Interventions Outcome Measures Eligibility Criteria Contacts and Locations More Information

Locations

United States, Massachusetts
Massachusetts General Hospital
Boston, Massachusetts, United States, 02114

Sponsors and Collaborators

Massachusetts General Hospital

Investigators

Principal Investigator:	Hideo Makimura, MD, PhD	Massachusetts General Hospital

More Information

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Study Description Study Design Arms and Interventions Outcome Measures Eligibility Criteria Contacts and Locations More Information

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
First Posted:	February 23, 2012
Last Update Posted:	December 13, 2013
Last Verified:	December 2013

Keywords provided by Hideo Makimura, Massachusetts General Hospital:

low vitamin c; reduced growth hormone secretion

Additional relevant MeSH terms:

Vitamins; Ascorbic Acid; Hormones; Micronutrients; Growth Substances	Physiological Effects of Drugs; Hormones, Hormone Substitutes, and Hormone Antagonists; Antioxidants; Molecular Mechanisms of Pharmacological Action; Protective Agents