Chapter 17: Nutritional Assessment, Therapeutic Diets, and Infant Feeding

INTRODUCTION

INTERPLAY BETWEEN NUTRITION AND ILLNESS

Nutritional factors figure prominently in the pathogenesis of coronary heart disease, cancer, stroke, and type 2 diabetes—diseases that account for more than half of all deaths in the United States. This situation is compounded by the epidemic of obesity in the United States, which is expected to cause sharp increases in the incidence of chronic illness.

However, the link between nutritional status and health risk extends beyond chronic disease to include acute illness. Surveys place the incidence of malnutrition among hospitalized patients between 30% and 55%. Malnutrition increases the risk of adverse clinical outcomes of hospital stays. In short, poor nutrition increases the risk of becoming ill, and when illness does strike, malnutrition complicates treatment and impairs recovery (Table 17-1).

By integrating nutritional assessment into the evaluation of all patients, clinicians not only identify malnutrition but also uncover risk factors for chronic disease and unfavorable clinical outcome, determine nutritional requirements, recognize people likely to benefit from nutritional support, and establish a framework for developing a therapeutic plan. Depending on the clinical setting, nutritional support can be provided through dietary oral intake, enteral tube feedings, or the parenteral route. This chapter focuses on the principles of nutritional assessment and oral therapeutic diets. Chapter 18, Enteral and Parenteral Nutrition, describes those approaches to nutritional support.

NUTRITIONAL ASSESSMENT

No single assessment technique has the validity to serve as the sole indicator of nutritional status. Nutritional assessment is a comprehensive process that combines objective data with relevant clinical information. Evaluate body composition, anthropometric measurements, and results of laboratory tests, and use the data in the context of the patient’s history, physical examination findings, and clinical condition to make decisions concerning nutritional status.

Body Weight

Body weight is a reliable indicator of nutritional status. Details concerning body weight include deviation of weight from ideal level, change in weight over time, and relation between weight and height. Body weight 20% over or under the ideal level places a patient at nutritional risk. Numerous methods for determining ideal body weight exist, but the Hamwi formula is the most widely used in clinical settings because the calculation is simple and provides a ...