Quantitative clinical nutrition approaches to the study of calcium and bone metabolism

Abstract

Understanding the role of nutrients, food components, and diet in bone health is important as a means available to individuals to build and maintain peak bone mass within their genetic potential. There are several approaches an investigator can take to study the relationship between diet and bone, including epidemiology, randomized controlled trials, or metabolic balance and kinetic studies. In this chapter, we will review methodologies that allow quantitative nutrition effects on bone to be determined. They are resource intensive, and thus, not feasible to use in large population studies. The necessarily small study group cannot represent the entire population, which is a limitation of this approach. Metabolic balance studies can offer a highly controlled independent variable, that is, diet. When used in a crossover design, the effect of one dietary change on net calcium retention can be quantitated. Kinetic studies provide additional information over balance studies alone, and analysis of tracers offers greater precision. When balance studies are used in conjunction with isotopic tracers, parameters of calcium metabolism can be studied including absorption, endogenous secretion, excretion, bone formation rates, and bone resorption rates. As 99 % of the body’s calcium resides in the skeleton, to study calcium metabolism is to study bone metabolism.