Date of Award

2013

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Nutrition Science

First Advisor

Connie Weaver

Committee Chair

Connie Weaver

Committee Member 1

Kim Buhman

Committee Member 2

Scott Radcliffe

Committee Member 3

Sean Newcomer

Abstract

Recent secondary analyses have associated supplemental calcium use with increased risk for myocardial infarction and cardiovascular-related death in healthy, older adults. Subsequent concern over the safety of calcium supplements has spurred a calcium controversy, because calcium is a shortfall essential nutrient that is critical for bone health and a mainstay of osteoporosis prevention and treatment. The proposed mechanism by which calcium intake may detriment cardiovascular health is through the acceleration of coronary artery calcification (CAC), a clinical indicator of coronary artery disease (CAD) that has been associated with mortality risk. However, causal evidence to support this hypothesis is lacking. Determining causality between calcium intake and cardiovascular risk has been hindered by the long intervention period necessary to monitor disease progression in human populations and a lack of sensitive outcome measures to detect early vascular calcification.

The aim of this research was to assess the effect of high calcium consumption from calcium carbonate or dairy on cardiovascular function, CAD burden and coronary artery calcium deposition in the Ossabaw swine, a model that mimics human metabolic syndrome and CAD when fed an atherogenic diet. Pigs (n=24) were maintained on an atherogenic diet and randomized to one of

three calcium treatments including control calcium (0.5% Ca by weight), high calcium from calcium carbonate (2% Ca), or high

calcium from dairy (2% Ca) for 6 months. To sensitively assess CAC with calcium tracer kinetics, pigs were dosed with the rare isotope, 41Ca, that can be measured in blood and

tissues at a sensitivity of 10-18 M by Accelerator Mass Spectrometry (AMS). More traditional measures of cardiovascular health and disease were also utilized including computed tomography (CT), intravascular ultrasound (IVUS), histopathology and in vitro wire myography.

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