IGF1 and protein-energy malnutrition: Donahue and Phillips (1989)47 showed that decreased IGF-1 serum levels in hospitalized patients with protein or protein-energy malnutrition (39 ± 7 ng/ml) were more marked than in patients with energy malnutrition alone (109 ± 25 ng/ml), thus confirming the major role of protein intake in IGF-1 regulation.