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

March 27, 2023 updated by: Sue A. Shapses, Ph.D., RD, Rutgers University

Nutritional Regulation of Bone - Aim 3

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).

Study Overview

Status

Completed

Conditions

Intervention / Treatment

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.

Study Type

Interventional

Enrollment (Actual)

83

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • New Jersey
      • New Brunswick, New Jersey, United States, 08901
        • Rutgers University

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

50 years to 72 years (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

Female

Description

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 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)

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
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 6 weeks
Placebo Comparator: WM
Behavioral: Weight Maintenance
Diet for weight maintenance for 6 weeks
Active Comparator: WM + D
Dietary supplement: Vitamin D 2500 IU
Daily Vitamin D 2500 IU supplement for 6 weeks
Behavioral: Weight Maintenance
Diet for weight maintenance for 6 weeks

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Changes in Calcium absorption
Time Frame: 6 weeks
6 weeks

Secondary Outcome Measures

Outcome Measure
Time Frame
Changes in serum and urine bone markers, hormones, glucose, proteins and genes
Time Frame: 6 weeks
6 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Rutgers University

Collaborators

National Institute on Aging (NIA)

Investigators

  • Principal Investigator: Sue Shapses, PhD, Rutgers University, Nutritional Sciences

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

March 1, 2007

Primary Completion (Actual)

May 1, 2010

Study Completion (Actual)

March 1, 2011

Study Registration Dates

First Submitted

May 10, 2007

First Submitted That Met QC Criteria

May 10, 2007

First Posted (Estimate)

May 14, 2007

Study Record Updates

Last Update Posted (Actual)

March 28, 2023

Last Update Submitted That Met QC Criteria

March 27, 2023

Last Verified

January 1, 2022

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • AG0083
  • R01AG012161 (U.S. NIH Grant/Contract)
  • AG012161

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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