Effect of Caloric Restriction on Bone Mineral Density and Bone Turnover in Over Weight and Obese Individuals with Differing Calcium Intake Levels

<p>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: <strong>Low Calcium (LC) </strong>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; <strong>High Calcium (HC) </strong>a calcium-supplemented diet identical to the control diet, with the placebo replaced by 900 mg calcium; or <strong>High Dairy (HD)</strong> 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.</p>

Name thesis:degree_name

Doctor of Public Health (DrPH)

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Nutrition

Year

2004

Author dc:creator

• Radak, Timothy L.

Contributors dc:contributor

• Joan Sabaté
• Marta Van Loan
• Sujatha Rajaram

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

Statement dc: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.

Language dc:language

English

Repository record dc:identifier

https://scholarsrepository.llu.edu/etd/962

OAI identifier oai:identifier

oai:scholarsrepository.llu.edu:etd-2046