Hiroyuki Sagayama1, Yosuke Yamada2, Mamiko Ichikawa3, Emi Kondo4, Jun Yasukata5, Yoko Tanabe6, Yasuki Higaki5, Hideyuki Takahashi4. 1. Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan. sagayama.hiroyuki.ka@u.tsukuba.ac.jp. 2. National Institute of Health and Nutrition, Tokyo, Japan. 3. Institute of Sports Science and Medicine, Teikyo University, Tokyo, Japan. 4. Japan Institute of Sports Sciences, Tokyo, Japan. 5. Faculty of Sports and Health Science, Fukuoka University, Fukuoka, Japan. 6. Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan.
Abstract
PURPOSE: To evaluate the hydration of fat-free mass (FFM) in athletes and non-athletes. METHODS: We analyzed the data of 128 healthy young adults (athletes: 61 men, 36 women; non-athletes: 19 men, 12 women) using the two-component (2C), 3C and 4C models. Under-water weighing or air-displacement plethysmography and deuterium dilution methods were used for estimating body density and total body water, respectively. The bone mineral content (BMC) was determined using whole-body scans by dual-energy X-ray absorptiometry. RESULTS: There was no significant difference in FFM hydration between the athletes (men, 72.3 ± 1.3%; women, 71.8 ± 1.3%) and non-athletes (men, 72.1 ± 1.2%; women, 72.2% ± 1.0%) in the 3C model. The total mean FFM hydration (72.1% ± 1.3%) was similar to the corresponding value in the literature (~ 73%). The estimation error of the percentage fat by the 2C vs the 4C model was significantly and highly correlated with hydration (r = 0.96), BMC (r = - 0.70), and total body protein (r = - 0.86) in the 4C model FFM. CONCLUSION: Although FFM hydration was similar in athletes and non-athletes, it would be underestimated or overestimated when the 2C model is used for evaluation, and the biological FFM hydration value deviates from the 73% value inter-individually. Despite that this inter-individual variation in FFM hydration is low in terms of between-individual standard deviation (1.3%), the BMC and total body protein differ greatly in athletes, and when it affects FFM hydration, it may also affect the percentage fat measurement in the 2C model. Thus, FFM hydration would not be affected by FFM, percent body fat, or the athletic status.
PURPOSE: To evaluate the hydration of fat-free mass (FFM) in athletes and non-athletes. METHODS: We analyzed the data of 128 healthy young adults (athletes: 61 men, 36 women; non-athletes: 19 men, 12 women) using the two-component (2C), 3C and 4C models. Under-water weighing or air-displacement plethysmography and deuterium dilution methods were used for estimating body density and total body water, respectively. The bone mineral content (BMC) was determined using whole-body scans by dual-energy X-ray absorptiometry. RESULTS: There was no significant difference in FFM hydration between the athletes (men, 72.3 ± 1.3%; women, 71.8 ± 1.3%) and non-athletes (men, 72.1 ± 1.2%; women, 72.2% ± 1.0%) in the 3C model. The total mean FFM hydration (72.1% ± 1.3%) was similar to the corresponding value in the literature (~ 73%). The estimation error of the percentage fat by the 2C vs the 4C model was significantly and highly correlated with hydration (r = 0.96), BMC (r = - 0.70), and total body protein (r = - 0.86) in the 4C model FFM. CONCLUSION: Although FFM hydration was similar in athletes and non-athletes, it would be underestimated or overestimated when the 2C model is used for evaluation, and the biological FFM hydration value deviates from the 73% value inter-individually. Despite that this inter-individual variation in FFM hydration is low in terms of between-individual standard deviation (1.3%), the BMC and total body protein differ greatly in athletes, and when it affects FFM hydration, it may also affect the percentage fat measurement in the 2C model. Thus, FFM hydration would not be affected by FFM, percent body fat, or the athletic status.
Entities:
Keywords:
Body composition; Body density; Isotope ratio; Total body water
Authors: Desirée Gutiérrez-Marín; Veronica Luque; Natàlia Ferré; Mary S Fewtrell; Jane E Williams; Jonathan C K Wells Journal: Eur J Clin Nutr Date: 2019-07-08 Impact factor: 4.016
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