ADIPOSE-TISSUE DENSITY, ESTIMATED ADIPOSE LIPID FRACTION AND WHOLE-BODY ADIPOSITY IN MALE CADAVERS

Lipid and water together typically make up more than 90% of the body's adipose tissue mass. Although some reports have shown that the fracti on of lipid in adipose tissue is greater in obese people than in lean ones, the quantitative relationship between adipose lipid fraction and overall adiposity of the body has never been investigated. We dissect ed six male unembalmed cadavers and weighed all adipose tissue (range 9.7-25.7 kg), allowing the calculation of percentage adiposity as 100 x total adipose mass/body mass (range 17.8-43.9%). Adipose tissue volu me was determined by hydrostatic weighing of all portions of the disse cted adipose tissue. For the six cadavers, whole body adipose tissue d ensity ranged from 0.925-0.970 g/ml. Based on a three-component model of adipose tissue (lipid, water and dry fat-free solids), an expressio n for lipid fraction, F; was derived. After assuming densities for adi pose lipid (0.905 g/ml), water at 36 degrees C (0.997 g/ml) and the dr y fat-free component (1.38 g/ml), the equation simplified to F = 6.256 /D - 5.912, where D is adipose tissue density (g/ml). Lipid fraction w as then calculated for each of the six cadavers: the range (0.54 - 0.8 5) was in excellent agreement with published data. There was a signifi cant correlation (r = 0.95, P < 0.005) between calculated lipid fracti on and percentage adiposity. The regression equation predicting lipid fraction from percentage adiposity was y = 0.327 + 0.0124x. We conclud e that the estimated fraction of lipid in human adipose tissue shows b oth a wide range and a strong positive linear relationship with overal l body fatness.