beta-oxidation of linoleate in obese men undergoing weight loss

Background: In animals, the whole-body content and accumulation of linoleat e can be measured and compared with its intake to determine linoleate beta -oxidation. This method can also provide quantitative information about the beta -oxidation of linoleate in humans. Objectives: The objectives of the study were to 1) use the whole-body fatty acid balance method to quantify whole-body concentrations of linoleate in humans, 2) estimate the distribution of linoleate between adipose and lean tissue, and 3) assess the effect of weight loss on linoleate stores and bet a -oxidation in obese humans. Design: Nine healthy obese men underwent supervised weight loss for 112 d(1 6 wk). Magnetic resonance imaging data and fatty acid profiles from fat bio psies were both used to determine linoleate stores in adipose and lean tiss ue and in the whole body. Linoleate beta -oxidation was calculated as intak e - (accumulation + excretion). Results: Mean weight loss was 13 kg and linoleate intake was 24 +/- 6 mmol/ d over the study period. Whole-body loss of linoleate was 37 +/- 18 mmol/d, or 28% of the level before weight loss. Combining the intake and whole-bod y loss of linoleate resulted in linoleate beta -oxidation exceeding intake by 2.5-fold during the weight-loss period. Conclusions: All dietary linoleate is beta -oxidized and at least an equiva lent amount of linoleate is lost from the body during moderate weight loss in obese men. The method studied permits the assessment of long-term change s in linoleate homeostasis in obese humans and may be useful in determining the risk of linoleate deficiency in other conditions.