The lung

Malnutrition causes loss of lung tissue and a reduction in the size and contractility of the muscles associated with breathing, such as the diaphragm. Weak respiratory muscles are unable to generate sufficient cough pressure to effectively expectorate and clear the lung of secretions, which may be infected. This chapter focuses on chronic obstructive pulmonary disease (COPD), which encompasses both chronic bronchitis and emphysema. It provides an overview of both the causes of nutritional depletion in COPD and potential therapeutic targets. While nutritional support often focuses on the fat, carbohydrate, and protein content of the diet and supplements, the provision of other nutrients is also important, especially since micronutrient deficiencies may coexist with protein‐energy deficiency. Nutritional modulation of muscle metabolism by amino acids or other substrates and co‐factors may not only be relevant to tissue repletion of wasted patients, but also in anabolism induced by exercise training