British Journal of Nutrition

Research Article

Evaluation of the novel Tanita body-fat analyser to measure body composition by comparison with a four-compartment model

Susan A. Jebba1 c1, Timothy J. Colea1, Deanne Domana1, Peter R. Murgatroyda1 and Andrew M. Prenticea1

a1 MRC Human Nutrition Research (formerly Dunn Nutritional Laboratory), Downhams Lane, Cambridge, CB4 1XJ, UK

Abstract

The Tanita body-fat analyser is a novel device to estimate body fat, based on the principles of bioelectrical impedance. It differs from other impedance systems which use surface electrodes in that the subjects stand bare-footed on a metal sole-plate which incorporates the electrodes, hence impedance is measured through the legs and lower trunk. In 104 men and 101 women (16–78 years and BMI 16–41 kg/m2) the mean bias in body-fat mass measured using the Tanita body-fat analyser was 0·8 (2SD 7·9) KG RELATIVE TO A FOUR-COMPARTMENT MODEL. THIS IS COMPARABLE TO THE OTHER PREDICTION TECHNIQUES TESTED (CONVENTIONAL TETRAPOLAR IMPEDANCE -1·3 (2sd 6·9) kg, skinfold thicknesses 0·3 (2sd 7·4) kg, and BMI-based formulas -0·2 (2sd 9·0) kg and -0·6 (2sd 8·5) kg), but the agreement was poorer than for ‘reference’ methods to measure body fat (density 0·2 (2sd 3·7) kg, total body water -0·9 (2sd 3·4) kg and dual-energy X-ray absorptiometry 0·1 (2sd 5·0) kg). The present paper also describes the derivation of a new prediction equation for the calculation of body composition from the Tanita body-fat analyser. The equation incorporates sex, age, and a log-transformation of height, weight and the measured impedance to predict body fat measured by a four-compartment model. This approach is recommended in the derivation of other prediction equations in body composition analysis. Using this novel prediction equation the residual standard deviations were 4·8 % for men and 3·3 % for women. A similar analysis using data collected with a conventional tetrapolar system yielded residual standard deviations of 4·3 % for men and 3·1 % for women. This demonstrates that the practical simplicity of the novel Tanita method is not associated with a clinically significant decrement in performance relative to a traditional impedance device.

(Received January 18 1999)

(Revised July 30 1999)

(Accepted August 17 1999)

Correspondence:

c1 *Corresponding author: Dr Susan Jebb, fax +44 (0) 1223 426617, email Susan.Jebb@mrc-hnr.cam.ac.uk