Multi‐component molecular‐level body composition reference methods: evolving concepts and future directions

Abstract

Excess adiposity is the main phenotypic feature that defines human obesity and that plays a pathophysiological role in most chronic diseases. Measuring the amount of fat mass present is thus a central aspect of studying obesity at the individual and population levels. Nevertheless, a consensus is lacking among investigators on a single accepted “reference” approach for quantifying fat mass in vivo. While the research community generally relies on the multicomponent body-volume class of “reference” models for quantifying fat mass, no definable guide discerns among different applied equations for partitioning the four (fat, water, protein, and mineral mass) or more quantified components, standardizes “adjustment” or measurement system approaches for model-required labeled water dilution volumes and bone mineral mass estimates, or firmly establishes the body temperature at which model physical properties are assumed. The resulting differing reference strategies for quantifying body composition in vivo leads to small but under some circumstances important differences in the amount of measured body fat. Recent technological advances highlight opportunities to expand model applications to new subject groups and measured components such as total body protein. The current report reviews the historical evolution of multicomponent body volume-based methods in the context of prevailing uncertainties and future potential.

Thigh and calf circumference for the sarcopenia screening in community-dwelling elderly women

“…The specific gravity of fat is 0.900 g/cm 3 and the specific gravity of lean body mass is 1.095/cm 3 . 10,11 This means that fat is weight less per 1 cm 3 , but volume is larger. It has been reported that the fat mass of the thigh muscle in sarcopenia is increased compared to non sarcopenia.…”

Body composition in clinical practice

“…Recent technological advances highlight the opportunities to expand model applications to new subject groups and measure components such as total body protein [11].…”

“…He conceived of the human body as two components, fat and "lean body mass", each with an assumed stable density of 0.900 g/cm 3 and 1.095 g/cm 3 , respectively [10][11][12].…”

Assessment methods of body composition

“…Međutim, danas druge tehnike procene telesne kompozicije, kao što su određivanje ukupnog telesnog kalijuma (TBK), ukupne telesne vode (TBW), DXA i magnetna rezonanca zauzimaju vodeće mesto u proceni telesnog sastava. Takođe postoje i multikomponentni hemijski metodi koji uključuju više od jedne metode procene i korisni su za aplikaciju u primenjenim istraživanjima [7]. …”