HIGH COGNITIVE DIETARY RESTRAINT IS ASSOCIATED WITH INCREASED CORTISOL EXCRETION IN POSTMENOPAUSAL WOMEN: A COMMENT

Abstract

To the Editor: I read with great interest the paper of Rideout and colleagues (1) who claimed that ‘‘our finding of higher cortisol excretion in postmenopausal women with high cognitive dietary restraint suggests that high dietary restraint may be a source of stress for generally healthy, normal-weight postmenopausal women’’ (p. 631). A shortcoming may confound their work, making the interpretation of their endocrine results difficult, if not impossible. The shortcoming is: The authors measured urinary ‘‘cortisol’’ (probably: urinary free ‘‘cortisol’’) by a competitive chemiluminescent immunoassay (Bayer ADVIA Centaur) that lacks specificity. Gray and colleagues (2) had evaluated this immunoassay and compared their values of urinary free cortisol (UFF) with those obtained by a specific gas chromatography–mass spectrometry method. They observed that cortisone, a major metabolite of UFF in the urine, demonstrated a crossreactivity of 44%, and they concluded that this method overestimates urinary cortisol, giving results up to twice those obtained by a specific gas chromatography–mass spectrometry method. Thus, we may assume that Rideout