Undernutrition, particularly protein undernutrition, contributes to the occ
urrence of osteoporotic fracture, by lowering bone mass and altering muscle
strength. Furthermore, the rate of medical complications after fracture ca
n also be increased by nutritional deficiency. The IGF-I system appears to
be directly involved in the pathogenetic mechanisms leading to osteoporotic
hip fracture in elderly and to its complications. In the presence of adequ
ate calcium and vitamin D supplies, protein supplements increasing the inta
kes from low to normal, raises IGF-I levels, improves the clinical outcome
after hip fracture, and attenuates the decrease in proximal femur bone mine
ral density in the year following the fracture. This nutritional approach i
s associated with a significant reduction of the stay in rehabilitation hos
pital. This underlines the importance of nutritional supports in preventing
and healing osteoporotic fractures.