Nutrition, âge et muscle : sarcopénie ou sarcoporose ?

One of the major impact of the metabolic aging is the reduction of lean body mass which corresponds to a loss of protein, especially in muscle also called sarcopenia. These alterations lead to a decrease in muscle strength leading to a gradual disability and ultimately to an over-morbidity with a social cost still largely unestimated. Therefore, the need to better define this clinical entity in terms of risk is an important objective of the nutritional care. The balance between the process of synthesis and breakdown of proteins result in a positive or negative protein mass, but these changes are difficult to demonstrate in the postabsorptive state in the elderly subjects. However, aging causes a gradual reduction in their muscle capacity to respond to food intake. Thus, in the elderly a lesser postprandial stimulation of protein synthesis, leading to a progressive daily loss of protein was reported as a result of incomplete compensation by post-prandial anabolism of body protein mobilization during post-absorptive state. The decline in physical activity is also an event to consider while in the elderly the muscle contraction induced anabolism still exists and can be used to maintain lean body mass. Based on these observations, new strategies to improve the availability postprandial amino acid can be used and could be combined with nutritional factors, physical and/or hormonal treatments.