Cysteine and obesity

Abstract

The strongest evidence so far linking cysteine with obesity is from epidemiologic data. Population studies consistently show a positive association of plasma tCys and blood-free cysteine with BMI and/or fat mass, which is largely not shared by upstream or downstream sulfur amino acids. Furthermore, the association appears independent of lifestyle, dietary, and plasma confounders. Although some of these studies are longitudinal, they cannot establish causality. Recent animal studies implicate cysteine in regulating lipid and energy metabolism, but a clear obesogenic action of exogenous cysteine on top of a normal diet is yet to be demonstrated in animals and humans. Nevertheless, collective data from epidemiologic studies, genetic syndromes, animal experiments and in vitro findings suggest that increased cysteine availability may increase body fat, and provide sufficient evidence to stimulate systematic investigation of this potential novel obesity risk factor. © 2011 The Obesity Society.