Clinical consequences of undernutrition in the elderly

A common problem: Undernutrition occurs when nutrient intake does not meet nutritional needs. Selective food intake induced micronutrient deficits (moderate undernutrition) and can later lead to protein calorie malnutrition (PCM). PCM is often discovered during acute illness (increased nutritional needs). PCM is observed in 30 to 50% of the institutionalized population and in 2 - 4% of the elderly living at home. Micronutrient deficits are far more frequent and concern 4 million elderly persons in France. Age-related changes: Decreased smell and taste capacities and the inability to modify eating habits in stress conditions are mainly responsible for low food intake. Low intake leads to immunodeficiency, and subsequent frailty. Any intercurrent illness aggravates both undernutrition and immunodeficiency, creating a disease-to-disease spiral (undernutrition-immunodeficiency) that is difficult to inverse. Signs of PCM: Early signs of protein-calorie malnutrition are nonspecific: fatigue, apathy, decline in muscle strength. It is important to diagnose undernutrition at this stage before more specific symptoms develop: anorexia, weight loss, infection. Metabolic disorders occur at a later stage, generally during an acute illness, leading to overt PCM with perturbed glucose metabolism, recurrent infection, dehydratation, impaired wound healing, and calcium bone loss. The length of refeeding therapy depends on the intensity of the clinical signs, weight loss, dehydratation, glucose metabolism disorder and/or on the severity of clinical complications such as infection or bone fractures. Practical attitude: Under nutrition must be recognized early at the stage of nonspecific clinical expression. Practitioners must be constantly aware of the risk of undernutrition and search for nonspecific signs in the elderly.