Insulin-like growth factor 1 (IGF-1), a nutritional marker in patients with eating disorders

Though low levels of insulin-like growth factor-1 (IGF-1) have been repeatedly reported in patients with eating disorders, the nutritional significance of IGF-1 has not been evaluated. The study aimed to assess the utility of IGF-1 for screening malnutrition and for monitoring nutrition intervention in patients with eating disorders.

IGF-1 and nutritional status were evaluated in 82 patients, 59 with anorexia nervosa (AN), and 23 with bulimia nervosa (BN). Nutritional assessment included the evaluation of body mass index (BMI), body fat (FAT) and muscle mass (MM), assessed by skinfold anthropometry, serum albumin, transthyretin and retinol-binding protein, energy and protein intake. IGF-1 and nutritional parameters were reevaluated in the early phase of refeeding (2-4 weeks) in 20 AN patients who entered a refeeding program.

Mean IGF-1 z-score was -1.74+/-0.74 in AN, and -0.74+/-0.91 in BN. Serum proteins were reduced in only a minority of patients. IGF-1 correlated with BMI (r=0.64), FAT (r=0.57), MAMC (mid-arm muscle circumference) (r=0.58) and MM (r=0.66) (P<0.001), while it did not correlate with serum proteins. In the early phase of nutritional repletion serum proteins and anthropometric parameters did not vary significantly, while a prompt and marked increase (73.9%) of IGF-1 was observed.

IGF-1 represents a biochemical marker of malnutrition and a sensitive index of nutritional repletion in patients with eating disorders.