Nutrition & Metabolism

1. Nutrition & Metabolism CHAPTER 26

2. Assessing Nutritional Status • A nutritional assessment determines a patient’s health from a nutritional perspective. • A complete nutritional assessment consists of the patient’s history, body measurements, a physical examination, and laboratory tests. • The patient history provides information about the risk factors for poor nutrition, which can be divided into four broad categories: • Health history • Socioeconomic status • Medications • Dietary history

3. Assessing Nutritional Status • After the dietary history is completed, various physical measurements are taken to determine body composition and development. These include the following: • Height, weight, and (in children) head circumference • Midarm circumference • Waist-to-hip ratio • Fat fold measurements

4. Providing Nutritional Support • Nutritional support is classified as enteral or parenteral. • In enteral nutrition, a nutritional supplement is given to the patient either orally or through a “feeding tube.” • Enteral tube alimentation uses a nasogastric or nasoduodenal tube placed into the nose and down the esophagus to deliver nutrients directly into the duodenum or just proximal to it. • Parenteral nutrition provides either partial or total nutrition intravenously. It is called partial parenteralnutrionwhen certain nutrients are given intravenously to supplement oral intake and total parenteral nutrition (TPN) when all of the patient’s nutrition is given this way.

5. Undernutrition • Malnutrition is any form of improper nutrition resulting from any cause: undereating, overeating, an imbalanced diet, or disturbances in the body’s ability to absorb and use specific nutrients. • Here we discuss one side of the issue, undernutrition, which is malnutrition that results from inadequate food intake or defects in the digestion, absorption, and use of nutrients. • Undernutrition progresses through four stages: • Reduced nutrient levels in the blood and other tissues • Changes in cellular enzyme activity due to lack of nutrients • Tissue and organ dysfunction • Outward signs of under nutrition such as weight loss and lethargy

6. Starvation • Starvation is the prolonged deprivation of all food. • Starvation is one of several conditions that activate the stress response described in your textbook. • Liver glycogen is broken down (glycogenolysis) and its glucose released into circulation. • Glycogen stores are depleted in just a few hours, and the body then resorts to gluconeogenesis, the conversion of other organic fuels into glucose. • This results in inanition, the general wasting away, weakness, depressed metabolism, and debility of the body as a person loses muscle mass and strength. • Inanition can also result from such conditions as malabsorption, cancer, and AIDS.)

7. Protein-Energy Malnutrition • Protein-energy malnutrition(PEM) is an inadequate intake of protein, calories, or both, typically seen in children under age 5 and usually in impoverished countries or in famines. • The two most common manifestations of PEM are as follows: • Marasmus • Kawshiorkor

8. Anorexia nervosa is the radical, self-imposed restriction of food intake for the purpose of staying thin. • Anorexia nervosa is diagnosed from a history of major weight loss in the absence of organic disease, with a body mass index (BMI) of 18 or less.

9. Bulimia Nervosa • Bulimia nervosa is similar to anorexia nervosa in its psychological cause, but different in habit and effect. • Bulimia literally means “ox-hunger.” • For all their efforts, bulimics usually do not lose a significant amount of weight. Antisocial and obsessive/compulsive behavior and self-mutilation are common bulimia.

10. Dieting and Weight Loss • Very few individuals seem satisfied with their body shape, and many want the “quick fix” offered by fad diets. • How can you recognize a fad diet? It is often easier than you might think, since they share a number of general characteristics: • The diet claims to produce rapid weight loss of more than 1% of total body weight per week. • The plan dictates that the dieter consume only certain foods or that calories may be drastically restricted. • The diet requires the user to eat only food that is provided by the company promoting it, often at high prices. • The diet claims to have a “special” or “magical” ingredient. • The promoters often try to cast suspicion on scientists, dietitians, and physicians. • Celebrities or past clients provide testimonials to the diet’s success.