Abstract

The purpose of this multi-center controlled study was to determine the effects of supplemental calcium, dairy products, and dietary calcium on bone metabolism during energy restriction. A total of 107 overweight or mildly obese males and premenopausal females between ages 18-35 years were recruited from the faculty, staff and student populations of each of the four participating institutions (University of Tennessee, Purdue University, Ohio State University and the University of California-Davis). Subjects were randomized to the following outpatient dietary regimens for 12 weeks: Low Calcium (LC) a control diet providing a 500 kcal/day deficit, 0-1 servings of dairy products/day, _< 500 mg calcium per day, and a daily placebo supplement; High Calcium (HC) a calcium-supplemented diet identical to the control diet, with the placebo replaced by 900 mg calcium; or High Dairy (HD) a high dairy diet (placebo supplemented) with a 500 kcal/day deficit and containing [greater than or equal to] 3 daily servings dairy products (milk, cheese and/or yogurt), for a total calcium intake of 1400 mg/day. Analysis of results revealed that all groups had significant weight loss (p<0.001). After adjusting for weight loss, LC had a significant decrease (1.201±.08 to 1.193±.07) in total body bone mineral density (BMD) (p<0.05), with a marginally significant increase (1.210±.12 to 1.227±.12) in lumbar BMD (p=0.076) for HC, and a significant increase (1.096±.12 to 1.100±.12) in femur BMD for HD (p<0.05). Lumbar bone mineral content (BMC) for HC had a significant increase (62.60±10 to 63.7411) (p<0.05) while total body and femur BMC remained unchanged for all groups. A significant difference between groups (p < 0.0l) was seen for bone alkaline phosphatase (BAP). Post-hoc analysis indicated a greater decline in BAP for HC (28.43±13.5 to 24.18±12.3), compared to LC (p<0.01) or HD (p<0.03); suggesting a suppression of bone turnover. No change in bone resorption (n-teleopeptide) occurred in any group. Our results suggest that a 12-wk, 500 kcal energy restriction diet with either HC or HD suppresses bone turnover which over time may result in preservation of bone mineral density. The current calcium intake in the general population already falls short of recommendations. Implications for public health professionals for the recommending of adequate intake levels of calcium during weight loss are discussed.

Department

Nutrition

School

School of Public Health

First Advisor

Joan Sabaté

Second Advisor

Marta Van Loan

Third Advisor

Sujatha Rajaram

Degree Name

Doctor of Public Health (DrPH)

Degree Level

Ph.D.

Year Degree Awarded

2004

Date (Title Page)

8-2004

Language

English

Library of Congress/MESH Subject Headings

Diet, Reducing; Bone Density; Bone Development; Biological Markers.

Type

Dissertation

Page Count

viii; 124

Digital Format

PDF

Digital Publisher

Loma Linda University Libraries

Usage Rights

This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.

Collection

Loma Linda University Electronic Theses and Dissertations

Collection Website

http://scholarsrepository.llu.edu/etd/

Repository

Loma Linda University. Del E. Webb Memorial Library. University Archives

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Nutrition Commons

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