Single, dual and multi-frequency bioimpedance to measure human body composition

The bioelectrical impedance analysis (BIA) methods. Operating at 50 kHz (single frequency), 1 and 100 kHz (dual frequency) and 5 to 500 kHz (multi-frequency) were used on 22 normal male human subjects, ages 20 to 50 years, for estimation of their body composition. The body compartments in terms of total body water (TBW), fat free mass (FFM) and fat mass (FM) did not show any difference statistically when measured by the dual and multi-frequency BIA methods. Single frequency BIA method, however, gave significantly different range of FM, FFM and TBW, than the dual and multi-frequency BIA measures. Biochemically determined body composition data would be necessary to evaluate the relative merits of these different frequency BIA modalities.