Improving Rehabilitation In Sarcopenia (IRIS)

Inclusion Criteria: * age 65 years or older * admission for physical rehabilitation * sarcopenia, measured with bioelectrical impedance assessment (BIA) + handgrip strength and gait speed * Mini Mental State Examination ≥18 * Informed consent Exclusion Criteria: * Any malignant disease during the last five years * Known kidney failure (previous glomerular filtration rate \<30 ml/min); * Known liver failure (Child B or C) * Psychiatric disease * Endocrine disorders associated with disorders of calcium metabolism (excluding osteoporosis) * Indications related to the study product: More than 10 µg (400 IU) of daily Vitamin D intake from medical sources More than 500 mg of daily calcium intake from medical sources. Adherence to a high energy or high protein diet up or use of protein containing or amino acid containing nutritional supplements up to three months before starting the study. * Known allergy to milk, milk products or other components of the proposed interventions * Indication to or ongoing artificial nutrition support * Inclusion in other nutrition intervention trials * Investigator's uncertainty about the willingness or ability of the subject to comply with the protocol requirements * Refusal