Keywords: ageing, muscle atrophy, protein in diet, muscle growth

This thesis is relevant to patients and elderly who are experiencing a loss of muscle mass. For the first time, it was demonstrated that from 20 grams of orally taken proteins, 11 grams enter the blood circulation and 2.2 grams are used to form new muscle tissue. Although insulin (a stimulating hormone) increases the uptake of amino acids (building stones of proteins) by tissues, unfortunately it does not increase muscle growth. We demonstrate that blood vessel quantity as well as quality are related to the amount of muscle mass. Finally, we stimulate muscle growth by the consumption of extra proteins at night, and by combining protein intake with artificial muscle contractions.