Nutrition.docx

Nutrition **Dr. Khaled A. Khader\ Associated Professor** **LEARNING OUTCOMES** After completing this chapter, you will be able to: 1. Identify essential nutrients and their dietary sources. 2. Describe normal digestion, absorption, and metabolism of carbohydrates, proteins, and lipids. 3...

Nutrition **Dr. Khaled A. Khader\ Associated Professor** **LEARNING OUTCOMES** After completing this chapter, you will be able to: 1. Identify essential nutrients and their dietary sources. 2. Describe normal digestion, absorption, and metabolism of carbohydrates, proteins, and lipids. 3. Identify factors influencing nutrition. 4. Identify nutritional variations throughout the life cycle. 5. Evaluate a diet using a food guide pyramid **LEARNING OUTCOMES** 6\. Discuss essential components and purposes of nutritional assessment and nutritional screening. 7\. Identify risk factors for and clinical signs of malnutrition. 8\. Describe nursing interventions to promote optimal nutrition. 9\. Discuss nursing interventions to treat clients with nutritional problems. **INTRODUCTION** **Nutrition** is the sum of all the interactions between an organism and the food it consumes. In other words, nutrition is what a person eats and how the body uses it. **Nutrients** are organic and inorganic substances found in foods that are required for body functioning. Adequate food intake consists of a balance of nutrients: water, carbohydrates, proteins, fats, vitamins, and minerals. Foods differ greatly in their **nutritive value** (the nutrient content of a specified amount of food), and no one food provides all essential nutrients. Nutrients have three major functions: providing energy for body processes and movement, providing structural material for body tissues, and regulating body processes. **ENERGY BALANCE** **Energy balance** is the relationship between the energy derived from food and the energy used by the body. The body obtains energy in the form of calories from carbohydrates, protein, fat, and alcohol. A person's energy balance is determined by comparing his or her energy intake with energy output. **Energy Intake** The amount of energy that nutrients or foods supply to the body is their caloric value. A **calorie** is a unit of heat energy. A **small calorie (c, cal)** is the amount of heat required to raise the temperature of 1 gram of water 1 degree Celsius. This unit of measure is used in chemistry and physics. A **large calorie (Calorie, kilocalorie \[Kcal\])** is the amount of heat energy required to raise the temperature of 1 gram of water 15 to 16 degrees Celsius and is the unit used in nutrition (although it is not universally capitalized). In the metric system, the measure is the **kilojoule (kJ)**. One Calorie (Kcal) equals 4.18 kilojoules. The energy liberated from the metabolism of food has been determined to be: 4 Calories/gram (17 kJ) of carbohydrates. 4 Calories/gram (17 kJ) of protein. 9 Calories/gram (38 kJ) of fat. 7 Calories/gram (29 kJ) of alcohol. **BODY WEIGHT AND BODY MASS STANDARDS** **Ideal body weight (IBW)** is the optimal weight recommended for optimal health. Many standardized tables and formulas were developed many years ago and are based on limited samples. The nurse should use great caution in suggesting that these weights apply to all clients. Many health professionals consider the body mass index to be a more reliable indicator of a person's healthy weight. For people older than 18 years, the **body mass index (BMI)** is an indicator of changes in body fat stores and whether a person's weight is appropriate for height and may provide a useful estimate of malnutrition. However, the results must be used with caution in people who have fluid retention (e.g., ascites or edema), athletes, or older adults. To calculate the BMI: 1. Measure the person's height in meters, e.g., 1.7 m (1 meter = 3.3 ft, or 39.6 in.) 2. Measure the weight in kilograms, e.g., 72 kg (1 kg = 2.2 pounds) 3. Calculate the BMI using the following formula: Another measure of body mass is percent body fat. Because BMI uses only height and weight, it can give misleading results for certain groups of clients such as athletes, frail older adults, and children. The most accurate percentage of body fat can be measured by underwater weighing and dual-energy x-ray absorptiometry (DEXA), but these methods are time consuming and expensive. Other indirect, but more practical measures include waist circumference, skinfold testing, and bioelectrical impedance analysis. **FACTORS AFFECTING NUTRITION** 1. **Development.** People in rapid periods of growth (i.e., infancy and adolescence) have increased needs for nutrients. Older adults, on the other hand, may need fewer calories and also need some dietary changes in view of their risk for coronary heart disease, osteoporosis, and hypertension. 2. **Sex.** Nutrient requirements are different for men and women because of body composition and reproductive functions. The larger muscle mass of men translates into a greater need for calories and proteins. Because of menstruation, women require more iron than men do prior to menopause. Pregnant and lactating women have increased caloric and fluid needs. 3. **Ethnicity and Culture.** Ethnicity often determines food preferences. Traditional foods (e.g., rice for Asians, pasta for Italians, curry for Indians) are eaten long after other customs are abandoned. 4. **Beliefs.** About Food Beliefs about effects of foods on health and well-being can affect food choices. Many people acquire their beliefs about food from television, magazines, and other media. 5. **Personal Preferences.** People develop likes and dislikes based on associations with a typical food. Preferences in the tastes, smells, flavors (blends of taste and smell), temperatures, colors, shapes, and sizes of food influence a person's food choices. Some people may prefer sweet and sour tastes to bitter or salty tastes. Textures play a great role in food preferences. Some people prefer crisp food to limp food, firm to soft, tender to tough, smooth to lumpy, or dry to soggy. 6. **Religious Practices**. 7. **Lifestyle.** Certain lifestyles are linked to food-related behaviors. People who are always in a hurry probably buy convenience grocery items or eat restaurant meals. People who spend many hours at home may take time to prepare more meals "from scratch." Individual differences also influence lifestyle patterns (e.g., cooking skills, concern about health). Some people work at different times, such as evening or night shifts. They might need to adapt their eating habits to this and also make changes in their medication schedules if they are related to food intake. Muscular activity affects metabolic rate more than any other factor; the more strenuous the activity, the greater the stimulation of the metabolism. Mental activity, which requires only about 4 Kcal per hour, provides very little metabolic stimulation. 8. **Economics.** What, how much, and how often a person eats are frequently affected by socioeconomic status. For example, people with limited income, including some older adults, may not be able to afford meat and fresh vegetables. In contrast, people with higher incomes may purchase more proteins and fats and fewer complex carbohydrates. 9. **Medications** **and Therapy** The effects of drugs on nutrition vary considerably. They may alter appetite, disturb taste perception, or interfere with nutrient absorption or excretion. Conversely, nutrients can affect drug utilization. Some nutrients can decrease drug absorption; others enhance absorption. Older adults are at particular risk for drug-- food interactions due to the number of medications they may take, age-related physiological changes affecting medication actions (e.g., decrease in lean-to-fat ratio, decrease in renal or hepatic function), and disease-restricted diets. Therapies prescribed for certain diseases (e.g., chemotherapy and radiation for cancer) may also adversely affect eating patterns and nutrition. Radiotherapy of the head and neck may cause decreased salivation, taste distortions, and swallowing difficulties; radiotherapy of the abdomen and pelvis may cause malabsorption, nausea, vomiting, and diarrhea. 10. **Health** An individual's health status greatly affects eating habits and nutritional status. Missing teeth, ill-fitting dentures, or a sore mouth makes chewing food difficult. Difficulty swallowing (dysphagia) due to a painfully inflamed throat or a stricture of the esophagus can prevent a person from obtaining adequate nourishment. Disease processes and surgery of the GI tract can affect digestion, absorption, metabolism, and excretion of essential nutrients. GI and other diseases also create nausea, vomiting, and diarrhea, all of which can adversely affect a person's appetite and nutritional status. Gallstones, which can block the flow of bile, are a common cause of impaired lipid digestion.. Autoimmune and genetic disorders such as celiac disease and irritable bowel syndrome may be worsened when eating foods containing wheat or gluten. 11. **Alcohol Consumption** The calories in alcoholic drinks include both those of the alcohol itself and of the juices or other beverages added to the drink. These can constitute large numbers of calories; A small amount of the alcohol is converted directly to fat. Excessive alcohol use contributes to nutritional deficiencies in several ways. Alcohol may replace food in a person's diet, and it can depress the appetite. Excessive alcohol can have a toxic effect on the intestinal mucosa, thereby decreasing the absorption of nutrients. The need for vitamin B increases, because it is used in alcohol metabolism. 12. **Advertising** Food producers try to persuade people to change from the product they currently use to the brand of the producer. Popular actors are often used in television, radio, Internet, and print to influence consumers' choices. 13. **Psychological Factors** Although some people overeat when stressed, depressed, or lonely, others eat very little under the same conditions. **Anorexia** and weight loss can indicate severe stress or depression. **Anorexia nervosa** and **bulimia** are severe psychophysiological conditions seen most frequently in female adolescents. **NUTRITIONAL VARIATIONS THROUGHOUT THE LIFE CYCLE** **Neonate to 1 Year** The newborn infant is usually fed "on demand." **Demand feeding** means that the child is fed when hungry rather than on a set time schedule. **Regurgitation**, or spitting up, during or after a feeding is a common occurrence during the first year. Although this may concern parents, it does not usually result in nutritional deficiency. At about 6 months of age, infants require iron supplementation to prevent **iron deficiency anemia.** **bottle mouth syndrome**. The term describes decay of the teeth caused by constant contact with sweet liquid from the bottle. **Toddler** Toddlers can eat most foods and adjust to three meals each day. Toddlers' fine motor skills are sufficiently well developed for them to learn how to feed themselves. By age 3, when most of the deciduous teeth have emerged, the toddler can bite and chew adult table food. **Preschooler** The preschooler eats adult foods. Active children often require snacks between meals. **School-Age Child.** School-age children require a balanced diet including approximately 1,600 to 2,200 Kcal/day. Children need a protein-rich food at breakfast to sustain the prolonged physical and mental effort required at school. Poor eating habits may cause obesity. **Adolescent.** The adolescent's need for nutrients and calories increases, particularly during the growth spurt. In particular, the need for protein, calcium, vitamin D, iron, and B vitamins increases during adolescence**.** Parents and nurses can promote better lifelong eating habits by encouraging teenagers to eat healthy snacks. **Anorexia nervosa** is characterized by a prolonged inability or refusal to eat, rapid weight loss, and emaciation in individuals who continue to believe they are fat. **Bulimia** is an uncontrollable compulsion to consume enormous amounts of food (binge) and then expel it by self-induced vomiting or by taking laxatives (purge). Young Adult. Young adult females need to maintain adequate iron intake. Calcium is needed in young adulthood to maintain bones. Along with calcium, the person must have adequate vitamin D, necessary for the calcium to enter the bloodstream. Low-fat and/or low-cholesterol diets play a significant role in both the prevention and treatment of CV disease. Middle-Aged Adult. Need special attention to protein and calcium intake and limiting cholesterol and caloric intake. Two or three liters of fluid should be included in the daily diet. Postmenopausal women need to ingest sufficient calcium and vitamin D to reduce osteoporosis, and antioxidants such as vitamins A, C, and E may be helpful in reducing the risks of heart disease in women. **Older Adults** fewer calories are needed by older adults because of the lower metabolic rate and the decrease in physical activity**.** Psychosocial factors may also contribute to nutritional problems. Some older adults who live alone do not want to cook for themselves or eat alone. lack of transportation, poor access to stores, and inability to prepare the food also affect nutritional status. Loss of spouse, anxiety, depression, dependence on others, and lowered income all affect eating habits. **STANDARDS FOR A HEALTHY DIET** Dietary Guidelines for Americans. This guide is published by the USDA every 5 years, and the 2010 edition contains recommendations for the total diet that allows food choices that result in a nutrient-rich and calorie-balanced intake. Key points of the latest dietary guidelines follow: - Shift to more plant-based foods such as vegetables, fruits, grains, beans, and nuts. - Significantly reduce foods with added sugars and solid fats. - Engage in regular physical activity. - Consume foods, including milk products, each day that increase commonly insufficient nutrients: vitamin D, calcium, potassium, and fiber. - Keep daily total fat intake within 20% to 35% of total calories, less than 7% from saturated fatty acids and less than 300 mg cholesterol. - Consume less than 1,500 mg of sodium per day. - If you drink alcohol, do so in moderation (one drink per day for women and two drinks per day for men). **Vegetarian Diets** People may become vegetarians for economic, health, religious, ethical, or ecologic reasons. There are two basic vegetarian diets: those that use only plant foods (vegan) and those that include milk, eggs, or dairy products. Some people eat fish and poultry but not beef, lamb, or pork; others eat only fresh fruit, juices, and nuts; and still others eat plant foods and dairy products but not eggs. Foods of animal origin are the best source of vitamin B12. Therefore, vegans need to obtain this vitamin from other sources: brewer's yeast, foods fortified with vitamin B12, or a vitamin supplement. Because iron from plant sources is not absorbed as efficiently as iron from meat, vegans should eat iron-rich foods (e.g., green leafy vegetables, whole grains, raisins, and molasses) and iron-enriched foods. They should eat a food rich in vitamin C at each meal to enhance iron absorption. Calcium deficiency is a concern only for strict vegetarians. It can be prevented by including in the diet soybean milk and tofu (soybean curd) fortified with calcium and leafy green vegetables. **ALTERED NUTRITION** **Malnutrition** is commonly defined as the lack of necessary or appropriate food substances, but in practice includes both undernutrition and overnutrition. **Overnutrition** refers to a caloric intake in excess of daily energy requirements, resulting in storage of energy in the form of adipose tissue. As the amount of stored fat increases, the individual becomes overweight or obese. A person is said to be **overweight** when the BMI is between 25 and 29.9 kg/m2 and **obese** when the BMI is \>30 kg/m2. **Undernutrition** refers to an intake of nutrients insufficient to meet daily energy requirements because of inadequate food intake or improper digestion and absorption of food. **◯ NURSING MANAGEMENT** **Assessing** A nutritional assessment identifies clients at risk for malnutrition and those with poor nutritional status. In most health care facilities, the responsibility for nutritional assessment and support is shared by the primary care provider, the dietitian, and the nurse. **Nutritional Screening** Nurses perform a nutritional screen. A nutritional screen is an assessment performed to identify clients at risk for malnutrition or those who are malnourished. For clients who are found to be at moderate or high risk for malnutrition (BOX 47--5), follow-up is provided in the form of a comprehensive assessment by a dietitian. **Summary of Risk Factors for Nutritional Problems** **Components of a Nutritional Assessment** **Nursing History** As mentioned earlier, nurses obtain considerable nutrition-related data in the routine admission nursing history. Data include but are not limited to the following: Age, sex, and activity level Difficulty eating (e.g., impaired chewing or swallowing) Condition of the mouth, teeth, and presence of dentures Changes in appetite Changes in weight Physical disabilities that affect purchasing, preparing, and eating Cultural and religious beliefs that affect food choices Living arrangements (e.g., living alone) and economic status General health status and medical condition Medication history **Anthropometric** Measurements Anthropometric measurements are noninvasive techniques that aim to quantify body composition. A **skinfold measurement** is performed to determine fat stores. The most common site for measurement is the triceps skinfold (TSF). The fold of skin measured includes subcutaneous tissue but not the underlying muscle. The **mid-arm circumference (MAC)** is a measure of fat, muscle, and skeleton. To measure the MAC, ask the client to sit or stand with the arm hanging freely and the forearm flexed to horizontal. Measure the circumference at the midpoint of the arm, recording the measurement in centimeters, to the nearest millimeter (e.g., 24.6 cm). **Standard Values for Anthropometric Measurements for Adults** **Biochemical (Laboratory) Data** **Serum Proteins** Serum protein levels provide an estimate of visceral protein stores. Tests commonly include hemoglobin, albumin, transferrin, and total iron-binding capacity. A low hemoglobin level may be evidence of iron deficiency anemia. **Albumin**, which accounts for over 50% of the total serum proteins, is one of the most common visceral proteins evaluated as part of the nutritional assessment. Because there is so much albumin in the body and because it is not broken down very quickly (i.e., it has a half-life of 18 to 20 days), albumin concentrations change slowly. A low serum albumin level is a useful indicator of prolonged protein depletion rather than acute or short-term changes in nutritional status. However, many conditions besides malnutrition can depress albumin concentration, such as altered liver function, hydration status, and losses from open wounds and burns. **Transferrin** binds and carries iron from the intestine through the serum. Because it has a shorter half-life than albumin (8 to 9 days), transferrin responds more quickly to protein depletion than albumin. Serum transferrin can be measured directly or by a total iron-binding capacity (TIBC) test, which indicates the amount of iron in the blood to which transferrin can bind. Transferrin levels below normal are found with protein loss, iron deficiency anemia, pregnancy, hepatitis, or liver dysfunction. **Urinary Tests** Urinary urea nitrogen and urinary creatinine are measures of protein catabolism and the state of nitrogen balance. **Urea**, the chief end product of amino acid metabolism, is formed from ammonia detoxified by the liver, circulated in the blood, and transported to the kidneys for excretion in urine. Urea concentrations in the blood and urine, therefore, directly reflect the intake and breakdown of dietary protein, the rate of urea production in the liver, and the rate of urea removal by the kidneys. **Urinary creatinine** reflects a person's total muscle mass because creatinine is the chief end product of the creatine produced when energy is released during skeletal muscle metabolism. The rate of creatinine formation is directly proportional to the total muscle mass. Creatinine is removed from the bloodstream by the kidneys and excreted in the urine at a rate that closely parallels its formation. **Total Lymphocyte Count** The total number of lymphocyte white blood cells decreases as protein depletion