Alterations in vitamin A and thyroid hormone status in anorexia nervosa and associated disorders

Vitamin A and thyroid hormone status was investigated in 27 patients with anorexia nervosa. Subjects were divided into three groups based on eating behavior and serum carotene concentrations: anorexic (dietary restriction), normal carotene; anorexic, elevated serum carotene; bulimic, elevated serum carotene. All bulimic subjects fulfilling selection criteria were hypercarotenemic (weight loss and reduced metabolic rate). Data were compared to normal healthy volunteers. Serum retinol and retinol-binding protein levels were normal in all subjects whereas retinyl esters were elevated in the hypercarotenemic groups. Hypercarotenemia was primarily a result of elevation of vitamin A active carotenoids, especially β-carotene. Diet was excluded from the etiology of hypercarotenemia. Thyroid hormones T₄ and T₃ were significantly depressed in hypercarotenemic groups and rT₃ increased. A concomitant alteration in vitamin-hormone status is observed with progressive metabolic alterations: low T₃, T₄, and elevated retinyl esters in subjects with the hypercarotenemia associated with anorexia nervosa.