Skip to main content
ARS Home » Plains Area » Houston, Texas » Children's Nutrition Research Center » Research » Publications at this Location » Publication #80213
Title: ASSESSING TOTAL BODY PROTEIN, MINERAL AND BONE MINERAL CONTENT FROM TOTAL BODY WATER AND BODY DENSITY

Author
item SICONOLFI, STEVEN - NASA/JSC
item GRETEBECK, RANDAL - NASA/JSC
item Wong, William

Submitted to: Journal of Applied Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/15/1995
Publication Date: N/A
Citation: N/A

Interpretive Summary: Most researchers investigating body composition focus on indirect assessments of body fat by using measurements of body density and one or more of the fat-free mass components. Fat-free mass has three main components: total body water, mineral, and protein. An inexpensive, indirect assessment of bone mineral content and protein mass may be useful to NASA investigators and others studying osteoporosis and muscle atrophy. We hypothesized that researchers could assess bone mineral content, total body mineral and protein from body water and density based on a theory developed by W. E. Siri. We studied 31 subjects and compared the results of different measurements. We concluded that Siri's theory was correct and can be used appropriately by investigators examining the change in an astronaut's bone mineral content and protein mass during a long space flight.

Technical Abstract: We hypothesized that investigators could assess bone mineral content (BMC), total body mineral (M) and protein (P) from body water (W) and density (DB) based on the theory of W. E. Siri (Advances in Biological and Medical Physics, 1956, p. 239-280, and Techniques for Measuring Body Composition, 1961, p. 223-224) for body composition analysis. Siri used one or more of the body components and the densities of the body, fat (F), W, M, and P to estimate one of the remaining fractional masses. We compared M, BMC, P, F, and fat-free mass (FFM) in 31 subjects (15 women and 16 men) computed from measurements of W and DB with (4-compartment (4C) model)) and without (3-compartment (3C) model)) BMC (from dual X-ray absorptiometry). 4C model P was calculated by difference (P=FFM - W - M). Mean difference (P<0.05) ranged from 0.1 to 0.8%. Correlations (+/- standard error of estimate (%)) between 4C and 3C model values were significant (r=0.907 +/- 8.8, 0.907 +/- -8.7, 0.969 +/- 6.6, 0.998 +/- 2.0, and 0.999 +/- 0.7% for M, BMC, P, F, an FFM, respectively). We concluded that investigators can assess M,BMC, and P from W and DB.