The Effect of Vitamin D Supplementation During Caloric Restriction on Intestinal Calcium Absorption

This study has been completed.
Sponsor:
Collaborator:
Information provided by (Responsible Party):
Sue Shapses, Rutgers University
ClinicalTrials.gov Identifier:
NCT00472654
First received: May 10, 2007
Last updated: August 8, 2012
Last verified: July 2012
  Purpose

The purpose of this study is to learn how the amount of vitamin D supplementation influences intestinal fractional calcium absorption (a measure of the amount of calcium absorbed).


Condition Intervention
Weight Loss
Vitamin D or Placebo
Behavioral: Weight Loss
Dietary Supplement: Vitamin D 2500 IU
Behavioral: Weight Maintenance

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: Nutritional Regulation of Bone - Aim 3

Resource links provided by NLM:


Further study details as provided by Rutgers University:

Primary Outcome Measures:
  • Changes in Calcium absorption [ Time Frame: 6 weeks ] [ Designated as safety issue: No ]

Secondary Outcome Measures:
  • Changes in serum and urine bone markers, hormones, proteins and genes [ Time Frame: 6 weeks ] [ Designated as safety issue: No ]

Enrollment: 83
Study Start Date: March 2007
Study Completion Date: March 2011
Primary Completion Date: May 2010 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Placebo Comparator: WL Behavioral: Weight Loss
Diet for weight loss for 6 weeks; all weight loss participants will attend 6 weekly counseling sessions (about 50 minutes per session)
Experimental: WL + D Behavioral: Weight Loss
Diet for weight loss for 6 weeks; all weight loss participants will attend 6 weekly counseling sessions (about 50 minutes per session)
Dietary Supplement: Vitamin D 2500 IU
Daily Vitamin D 2500 IU supplement for 5 weeks
Placebo Comparator: WM Behavioral: Weight Maintenance
Diet for weight maintenance for 5 weeks
Active Comparator: WM + D Dietary Supplement: Vitamin D 2500 IU
Daily Vitamin D 2500 IU supplement for 5 weeks
Behavioral: Weight Maintenance
Diet for weight maintenance for 5 weeks

Detailed Description:

The extent of change in the amount of calcium that is absorbed with an increase in vitamin D supplementation is not known. This information is important for determining appropriate vitamin D requirements for optimal calcium absorption. During caloric restriction in postmenopausal women, we found that serum parathyroid hormone (PTH) explains 22% of the variance for the reduced calcium absorption (equivalent to 400 IU of Vitamin D per day). It is possible that higher dietary Vitamin D will increase serum 25-hydroxy-Vitamin D (25(OH)D) levels, offset serum PTH and thereby prevent a reduction in calcium absorption. This study seeks to determine if a high Vitamin D intake (a supplement of 2500 IU per day) can increase true fractional calcium absorption (TFCA) in postmenopausal women on a standard high-carbohydrate weight loss diet compared to weight maintenance, with the hypothesis that a high Vitamin D intake will raise serum 25(OH)D and offset the decline in TFCA during caloric restriction (vs. an increase in weight-stable women), and serum PTH will no longer be a major factor explaining changes in TFCA.

Participants will be recruited for both weight loss and weight maintenance, and all will be randomly assigned to take either 2500 IU per day vitamin D supplement or matching placebo. All weight loss participants will attend 5-6 weekly counseling sessions (about 50 minutes per session). All participants will be asked to take a daily vitamin/mineral supplement and, depending on their usual food intake, they may be asked to take a calcium tablet to meet the recommended intake throughout the study period. To measure calcium absorption before and after the 6 weeks of weight loss, participants will go to the study site after an overnight fast where an IV will be placed and the participant will receive an infusion of a stable calcium isotope and consume a 4 oz beverage that also contains a stable isotope of calcium. Blood will be drawn, and then the participant will be asked to collect all urine for the next 24 hours. Body composition (fat, muscle mass, and bone mineral density) will be measured by a dual-energy x-ray absorptiometry (DXA) machine and peripheral quantitative computer tomography (pQCT).

Participants will only be recruited in the winter and spring of each year.

  Eligibility

Ages Eligible for Study:   50 Years and older
Genders Eligible for Study:   Female
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • Postmenopausal women who are more than 2 years since last menses
  • Obese or overweight
  • Must live in the geographic vicinity of Rutgers University

Exclusion Criteria:

  • Currently on any medication known to influence calcium or bone metabolism, including HRT, or with evidence of diseases known to influence calcium metabolism (i.e. metabolic bone disease, hyperparathyroidism, untreated thyroid disease, significant immune, hepatic, or renal disease, significant cardiac disease [i.e., heart attack or stroke in the past 6 months., abnormal EKG], active malignancy or cancer therapy within the past year)
  • History of kidney stones
  • Weight gain or weight loss (5% of body wt) within 3 months prior to recruitment
  • Participation in other investigational studies during the 12-month study period
  • Travel for longer than 2 consecutive weeks during the study period
  • Usually have a very high or low intake of calcium (more than 1500 or less than 500 mg per day)
  Contacts and Locations
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Please refer to this study by its ClinicalTrials.gov identifier: NCT00472654

Locations
United States, New Jersey
Rutgers University
New Brunswick, New Jersey, United States, 08901
Sponsors and Collaborators
Rutgers University
Investigators
Principal Investigator: Sue Shapses, PhD Rutgers University, Nutritional Sciences
  More Information

Publications:
Responsible Party: Sue Shapses, Professor, Rutgers University
ClinicalTrials.gov Identifier: NCT00472654     History of Changes
Other Study ID Numbers: AG0083, 5R01AG012161, RO1-AG12161
Study First Received: May 10, 2007
Last Updated: August 8, 2012
Health Authority: United States: Federal Government

Keywords provided by Rutgers University:
bone mass
calcium absorption
bone quality
fracture risk

Additional relevant MeSH terms:
Weight Loss
Body Weight Changes
Body Weight
Signs and Symptoms
Vitamin D
Ergocalciferols
Vitamins
Bone Density Conservation Agents
Physiological Effects of Drugs
Pharmacologic Actions
Micronutrients
Growth Substances

ClinicalTrials.gov processed this record on July 23, 2014