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Chapter 7 Nutrition The science of food as it relates to optimal health and performance Physical Examination Preview Nutrition Assessment From the history and physical examination, assess the patient’s nutritional status, including the following: Recent growth, weight loss, or weight gain Chronic illnesses affecting nutritional status or intake Medication and supplement use Nutrition screen Assessment of nutrient intake Clinical signs or symptoms of nutrient or energy deficiency Laboratory values Nutrition Assessment (Cont.) Obtain the following anthropometric measurements and compare them to standardized tables: Standing height Weight Calculate body mass index Waist circumference Calculate waist-hip ratio Triceps skinfold (TSF) thickness and mid–upper arm circumference (MAMC) measurements; calculate midarm muscle circumference/midarm muscle area (MAMA) Anatomy and Physiology Anatomy and Physiology Food nourishes the body by supplying nutrients and calories to function in three ways: Provide energy for activities Provide for building and maintaining body tissue Regulate body processes Anatomy and Physiology (Cont.) The nutrients necessary to the body are classified as: Macronutrients Micronutrients Water Macronutrients Carbohydrate, protein, and fat are referred to as macronutrients because they are required in large amounts. These three macronutrients provide the calories needed to produce energy in the human body. Even though alcohol also provides calories (7/g), it is not required for any physiologic processes by the body and therefore is not discussed in detail in this chapter. Carbohydrate Carbohydrate, a nutrient found mostly in plants and in milk, is considered the body’s main source of energy. About 365 g is stored as glycogen in the liver and muscle tissues, which provides energy for only about 13 hours of moderate activity. Carbohydrate (Cont.) If more carbohydrates are eaten than are needed for energy, the excess is stored in fatty tissues throughout the body. It is recommended that carbohydrate content of the diet be at least 50% of total calories, with no less than 100 g being consumed per day. Carbohydrate (Cont.) Carbohydrates also serve major functions in vital organs: Liver Sparing the use of protein for energy and participating in specific detoxifying metabolic pathways Heart As glycogen stored in cardiac muscle Central nervous system As the only energy source to the brain Protein Protein, present in all animal and plant products, is essential to life. It is a part of more than half the organic matter in the body. Twenty different amino acids combine in different ways to form proteins. Nine amino acids are considered essential because they cannot be manufactured by the body and are essential for normal growth and development. Protein (Cont.) The major functions of protein include the following: Building and maintaining tissues Regulating internal water and acid-base balances Acting as a precursor for enzymes, antibodies, and several hormones If more protein is eaten than is needed for these major functions, the surplus either is used to supply energy or is stored as body fat if total calorie intake is in excess of needs. Protein (Cont.) It is recommended that protein content of the diet be 14% to 20% of total calories, or a daily minimum of: 13 g in infants 25 g in children 45 g in adults Fat Fat, which is present in fatty fish, animal, and some plant products (particularly the seeds of plants), is necessary as the main source of: Linolenic acid (omega-7 fatty acid) -Linolenic acid (omega-3 fatty acid) Fatty acids are essential for normal growth and development. Fat (Cont.) Other major functions of fat include the following: Synthesis and regulation of certain hormones Maintenance of tissue structure Nerve impulse transmission Memory storage Energy metabolism If more fat is eaten than is needed for these functions, the extra is stored in fatty tissues in the body. Fat (Cont.) Some fatty tissues, especially those under the skin and around the abdominal organs, serve additional purposes: As a reserve store of fuel to be used when calorie intake does not meet needs Support and protect organs from injury Prevent undue loss of heat from the body surface It is recommended that fat content of the diet be 25% to 35% of total calories, or at least 20 to 35 g/day. Micronutrients Substances that are required and stored in very small quantities by the body Vitamins Minerals (elements) Electrolytes Not used as a source of energy but are essential for: Growth Development Hundreds of metabolic processes that occur daily Micronutrients (Cont.) Vitamins and minerals must be taken in either through food or by supplement. Micronutrients cannot be metabolized by the body, except: Vitamin K and biotin (produced by certain intestinal microorganisms) Vitamin D (synthesized from cholesterol) Niacin (synthesized from tryptophan) Water Most vital nutrient; adult body is 55% to 65% water. An individual can exist without food for several weeks, but without water, an individual would last only a few days. Major functions: Provide turgor to body tissues Alter configuration of substances for metabolic processes Transport body nutrients and wastes Maintain stable body temperature Water (Cont.) There is a continual loss of water from the body by the: Kidneys as urine Lungs as water vapor in expired air Skin as perspiration Approximately 2 to 2½ L of water are lost daily, which are replaced by: Fluids taken in Water contained in solid foods eaten Water produced in the body as a result of oxidative processes Energy Requirements Total energy expenditure Resting energy expenditure (REE): largest Represents the energy expended by a person at rest under conditions of stable temperature Basal metabolic rate (BMR) is defined as the REE measured soon after awakening in the morning (12 hours after the last meal). The variability is less than 10%. Energy Requirements (Cont.) Total energy expenditure (Cont.) Physical activity: second largest Estimated energy requirements (EER) EER is defined as the average dietary energy intake (estimated calories needed per day) to maintain energy balance in a healthy individual based on age, gender, weight, height, and physical activity level (PAL). Energy Requirements (Cont.) Total energy expenditure (Cont.) Thermogenesis: smallest Metabolic response to food intake Accounts for about 7% of the total energy expended during a day Review of Related History History of Present Illness Weight loss Total weight lost, compared with usual weight Time period Desired weight loss Eating habits Undesired weight loss Associated symptoms Preoccupation with body weight or shape Medications Chemotherapy, diuretics, insulin, fluoxetine, diet pills, laxatives, hypoglycemics, herbal supplements History of Present Illness (Cont.) Weight gain Total weight gained Time period, sudden or gradual, desired or undesired, possibility of pregnancy Change in lifestyle Change in social aspects of eating, more meals eaten out of the home, change in lifestyle, activity, and stress levels Medications Steroids, oral contraceptives, antidepressants, insulin History of Present Illness (Cont.) Increased metabolic requirements Infancy, prematurity Fever, infection, burns, trauma, pregnancy, infancy, hyperthyroidism, cancer External losses, such as fistulas, wounds, abscesses, chronic blood loss, chronic dialysis Past Medical History Chronic illnesses Diabetes, congestive heart failure, hypothyroidism, hyperthyroidism, pancreatic insufficiency, chronic infection, inflammatory bowel disease, surgical resection of the gastrointestinal tract Previous weight loss or gain efforts Weight at 25 years, maximum body weight, minimum weight as an adult Previously diagnosed eating disorder, hypoglycemia Family History Obesity, dyslipidemia Constitutionally short or tall stature Genetic or metabolic disorder: diabetes Eating disorder: anorexia, bulimia Alcoholism Personal and Social History Nutrition Use of vitamin, mineral, herbal supplements Usual weight and height; current weight and height Use of alcohol, recreational/club drugs Adequate income for food purchases Ability to shop/prepare foods Typical mealtime situations Use of supplements, tube feeding, parenteral nutrition Dentition: dentures, missing teeth, gum disease Infants and Children Nutrition: breast-feeding, formula Intake of protein, calories, vitamins, and minerals adequate for growth Chronic illness: PKU, inborn errors of metabolism, cystic fibrosis Congenital anomalies: cleft palate, prematurity, neurologic disorders, tongue thrust, severe congenital heart defect Adolescents Nutrition Intake of protein, calories, vitamins, and minerals adequate for growth, fad diets Preoccupation with weight; not limited to girls Overconcern with developing muscle mass, losing body fat Excessive exercise Weighs self daily, boasts about weight loss, weight goals Omits perceived fattening foods and food groups from diet Pregnant Women Prepregnancy weight, age, eating patterns/disorders Weight gain and nutrient intake during pregnancy Potential risks: pica, alcohol, inadequate weight gain Lactation, nutrient intake during lactation Influence of disorders: diabetes, renal disease, others Older Adults Nutrition: weight gain or loss, adequate income for food purchases, interest in meals, medical nutrition therapy needs, number of daily meals Energy level, regular exercise/activities Chronic illnesses: diabetes, renal disease, cancer, heart disease Food/nutrient/medication interactions Examination and Findings Equipment Tape measure with millimeter markings Calculator Standing platform scale with height attachments Anthropometrics Procedures for accurately measuring: Height Weight Triceps skinfold Table of norms for relevant age and gender groups These measurements are useful in assessing patients’ nutritional status and risk for disease. Anthropometrics (Cont.) Body mass index (BMI) Formula used to assess nutritional status and total body fat Waist circumference Large waist circumference often associated with increased risk for type 2 diabetes, dyslipidemia, hypertension, and cardiovascular disease Monitoring over time may aid in predicting disease risk for cardiovascular and obesityrelated diseases Anthropometrics (Cont.) Waist-to-hip circumference ratio Not as helpful as the body mass index in assessing total body fat An excess proportion of trunk and abdominal fat (e.g., apple-shaped body) has a higher risk association with diabetes mellitus, dyslipidemia, metabolic syndrome, stroke, and ischemic heart disease than does a larger proportion of gluteal fat (e.g., pearshaped body). Determination of Diet Adequacy The history of an individual’s food intake allows estimation of the adequacy of the diet. 24-hour recall diet Most simple method for food intake history Food diary Most accurate and time-consuming method Measures of Nutrient Analysis Computerized nutrient analysis programs offer quickest and most efficient method of analyzing nutrient intake. Quickest method of estimating adequacy is simply comparing individual intake with recommended servings and portions listed in the MyPyramid food guide. Measures of Nutrient Analysis (Cont.) MyPyramid food guide Indicates number of servings from each food group Food-based guidance to help implement recommendations for the 2010 Dietary Guidelines for Americans Focus on nutrient dense food. Balancing calories Avoid oversize portions Half of the plate fruits and veggies Water instead of sugary drinks Measures of Nutrient Analysis (Cont.) Vegetarian diets Can meet all the recommendations for nutrients Key is variety, as well as amounts to meet calorie needs Five nutrients may be deficient: protein, calcium, iron, vitamin B12, and vitamin D Ethnic food guide pyramids Food guide pyramids for ethnic populations are available (e.g., Mediterranean, Indian, Mexican, and Asian) Measures of Nutrient Adequacy An individual’s diet can be measured for nutritional adequacy based on energy needs and/or a variety of macronutrients or micronutrients. Energy Fat Protein Vitamins, minerals, electrolytes Fiber Special Procedures Triceps skinfold thickness Approximately 50% of the body fat is present in the subcutaneous tissue layers Correlation exists between the triceps skinfold thickness and the body’s fat content Special Procedures (Cont.) Mid–upper arm circumference (MAMC) Estimate of muscle mass and available fat and protein stores Midarm muscle circumference/midarm muscle area (MAMA) Sensitive index of body protein reserves Biochemical Measurement Hemoglobin (g/100 mL) Hematocrit (%) Transferrin saturation (%) Serum albumin (g/100 mL) Serum cholesterol (CHOL) (mg/100 mL) Serum triglycerides (TRI) (mg/100 mL) High-density lipoproteins (HDL) (mg/100 mL) Low-density lipoproteins (LDL) (mg/100 mL) CHOL/HDL ratio Serum glucose (mg/100 mL) Hemoglobin A1c (%) Serum folate (ng/mL) Abnormalities Common Abnormalities Obesity Excessive proportion of total body fat Genetic, behavioral, and environmental factors contribute to the development of obesity Excess body fat develops as a result from energy imbalance of caloric intake and energy expenditure Disproportionately affects some racial groups (African Americans) and those of low socioeconomic status Common Abnormalities (Cont.) Obesity (Cont.) Body fat, especially visceral fat, increases the risk for numerous health problems, including type 2 diabetes, cardiovascular disease, dyslipidemia, and cancer. Medications (e.g., steroids) and certain disease processes (e.g., Cushing disease and polycystic ovarian syndrome) may cause weight gain and contribute to obesity. Common Abnormalities (Cont.) Anorexia nervosa Eating disorder classified by the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) as a psychiatric disease, characterized by low body weight and body image distortion. Cause unknown, but genetic, environmental, and sociocultural factors likely contribute to the development of anorexia. Adolescent and young adult women, usually from middle and upper class families, most commonly affected; also occurs in adolescent boys and men. Two types: restricting (food intake is voluntarily limited) and purging (patients engage in purging after eating). Common Abnormalities (Cont.) Bulimia nervosa Eating disorder DSM-IV classified as psychiatric disease Cause unknown, but genetic, environmental, and sociocultural factors likely to contribute Adolescent and young adult women most commonly affected Two types: purging and nonpurging (episodes followed by fasting or excessive exercising) Common Abnormalities (Cont.) Anemia Lower than normal number of circulating red blood cells Iron deficiency is most common cause Other causes: nutrient deficiency states including B12 and folate (see Table 7-9 to determine type of anemia based on laboratory values) Question 1 Carbohydrates are: A. Body’s main source of energy B. The result of fat breakdown C. Is broken down into amino acids D. Acts as a precursor for enzymes Question 2 Which of the following is a major function of dietary protein? A. Provides energy source for brain. B. Builds and maintains tissues. C. Participates in specific detoxifying metabolic pathways. D. Synthesizes and regulates of hormones. Question 3 Water is the most vital nutrient; the major functions include all of the following, except: A. Providing turgor to body tissues B. Transporting dissolved nutrients throughout the body C. Continuously lost from the body by expired air D. Maintains thermogenesis Question 4 The midarm muscle circumference is: A. Well accepted as a sensitive index body protein reserves B. Correlates with BMI C. Used in the diagnosis of obesity D. Helpful to determine fluid balance Question 5 Energy expended at rest under conditions of stable temperature is identified as: A. BMI B. REE C. BMR D. Thermogenesis