Nutrition
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NUTRITION I.
PRINCIPLES
OF
NUTRITION
nutrition – study of nutrients and how they are handled by the body as well as the impact of human behavior and environment on the process of nourishment nutrients – specific biochemical substances used by body for growth, development, activity, reproduction, lactation, health maintenance, and recovery from illness or injury - needs change throughout the life cycle in response to changes in body size, activity, growth, development, and state of health - considered essential because they either are not synthesized in the body or are made in insufficient amts. - - must be provided in diet or through supplements Classes:
3 – supply energy (carbohydrates, protein, lipids) 3 – regulate body processes (vitamins, minerals, water)
II.
DEFINITION
A.
ENERGY BALANCE - energy is derived or obtained from foods consumed - only carbohydrates, protein, and fat provide energy
OF
ENERGY
AS
RELATED
TO
NUTRITION
calories – energy in the diet measured in the form of kilocalories - energy in the body is used to carry on any kind of activity whether voluntary or involuntary - total daily energy expenditure is the sum of all calories used to perform physical activity, maintain basal metabolism, and digest, absorb, and metabolize food - if daily energy intake is equal to total daily energy expenditure, weight will remain stable - if energy intake is less than energy expended, weight will decrease - if energy intake exceeds energy expenditure, weight will increase B.
METABOLIC REQUIREMENTS basal metabolism – amt of energy required to carry on the involuntary activities of the body at rest, such as maintaining body temperature and muscle tone, producing and releasing secretions, propelling food through the gastrointestinal (GI) tract, inflating the lungs, and contracting the heart muscle - as amt of energy used on physical activity declines, proportion of calories used for basal metabolism increases - men have higher basal metabolic rate (BMR) than women because of their larger muscle mass BMR = 1 cal/kg of body weight per hour for men BMR = 0.9 cal/kg of body weight per hour for women
- factors that increase BMR include growth, infections, fever, emotional tension, extreme environmental temperatures, and elevated levels of certain hormones, especially epinephrine and thyroid hormones - factors that decrease BMR include aging, prolonged fasting, and sleep C.
SPECIFIC DYNAMIC ACTION (SDA) - ideal body weight (IBW) or health body weight is an estimate of optimal weight for optimal health Rule-of-Thumb (ROT) - determines ideal weight based on height Females: 100 lbs (for height of 5’) + 5 lbs for each additional inch over 5’ Males: 106 lbs (for height of 5’) + 6 lbs for each additional inch over 5’ (add or deduct 10% from this figure based on body frame size) Body Mass Index (BMI) – ratio of height to weight, providing a more accurate reflection of total body fat stores in general population Kilograms and Meters: Weight in Kilograms (2.2 lb = 1 kg)
Pounds and Inches: Weight in Pounds x
704.5 Height2 in meters (39.37 in = 1 m)
Height in Inches
- provides an estimation of relative risk factors for diseases such as heart disease, diabetes, and hypertension - may not be accurate for people such as athletes, with a large muscle mass, or people with edema - BMI of 25 is considered overweight, 30 or greater indicates obesity Methods of Calculating Calorie Requirements: 1. Resting Energy Equivalent (REE) – amt of calories necessary to maintain body at rest Male Ex.: 65 kg x 1 cal/kg x 24 hr = 1560 cal/day Female Ex.: 65 kg x 0.9 cal/kg x 24 hr = 1404 cal/day - determine calories needed for specific activity level - REE is multiplied by one of the following: light activity REE x 0.55 – 0.65 moderate REE x 0.65 – 0.7 heavy 1.0
REE x 0.75 –
Male Ex.: 1560 x 0.55 = 858 calories Female Ex.: 1404 x 0.55 = 772 calories - total REE and calories needed based on activity level Male Ex.: 1560 + 858 = 2418 calories Female Ex.: 1404 + 772 = 2176 calories D.
CLASSES OF NUTRIENTS 1. Carbohydrates – known as sugars and starches, are organic compounds composed of carbon, hydrogen, and oxygen - only animal source of carbohydrate in the diet is lactose, or “milk sugar” - relatively easy to produce and store, most abundant and least expensive course of calories in diet - more easily and quickly digested than protein and fat - converted to glucose for transport through the blood or for use as energy - cells oxidize (burn) glucose to provide energy, carbon dioxide, and water - depending on person’s state of energy balance, the period between when carbohydrate is consumed and when it is used for energy may vary from minute to months or longer - when supply of glucose exceeds what is needed for energy and for maintaining serum levels, it is stored - when glycogen stores are adequate, body converts excess glucose to fat and stores it as triglycerides in adipose tissue Classifications: simple sugars (monosaccharides and disaccharides) complex sugars (polysaccharides) recommended dietary allowance (RDA) – recommendations for average daily amts that healthy population groups should consume over time ketosis – abnormal accumulation of ketone bodies that is frequently associated with acidosis 2.
Protein – vital component of every living cell - classified as essential because they cannot be synthesized in the
body - remaining amino acids are no less important but because the body can make them if a
supply of nitrogen is available, they are termed nonessential - excess amino acids are converted to fatty acids, ketone bodies, or glucose and are stored or used as metabolic fuel - required for formation of all body structures, including genes, enzymes, muscle, bone matrix, and hemoglobin - RDA for adults is 0.8 g/kg of desirable body weight, or about 56 g for avg. woman and 63 g for avg. man - stress of illness, surgery, or prolonged periods of time on simple IV without oral intake places patients at risk for developing protein-calorie malnutrition (PCM), resulting in weakness, poor wound healing, mental apathy, and edema catabolism – tissues continuously being broken down anabolism – tissues continuously being replaced - when both are occurring at the same rate, the body is in a state of neutral nitrogen balance - positive nitrogen balance occurs when nitrogen intake is greater than excretion (during periods of growth, pregnancy, lactation, and recovery from illness) - negative nitrogen balance, an undesirable state that occurs in situations such as starvation and catabolism that immediately follows surgery, illness, trauma, and stress, indicates that more nitrogen is being excreted than consumed 3.
Fats / Lipids – insoluble in water and, therefore, insoluble in blood - lipids in the diet are in the form of triglycerides, the predominant form of fat in food and major storage form of fat in the body - difference in degree of saturation depends on the amt of hydrogen in fat molecules - saturated fats tend to raise serum cholesterol levels, whereas unsaturated fats lower serum cholesterol levels trans fat – partially hydrogenate liquid oils, they become more solid and more stable - raises serum cholesterol cholesterol – fatlike substance found only in animal products
- need not be provided in the diet because the body synthesizes about twice as much cholesterol as most people eat - important component of cell membranes, especially abundant in brain and nerve cells - used to synthesize bile acids and is precursor of steroid hormones and vitamin D - to help lower serum cholesterol levels, eat less total fat – especially saturated and trans fat – eat more unsaturated fat, and increase fiber intake, which increases fecal excretion 4.
Regulatory Nutrients a. Vitamins – organic compounds needed by the body in small
amounts - active in form of coenzymes together with enzymes, facilitate thousands of chemical reactions in the body - needed for metabolism of carbohydrates, protein, and fat - may be destroyed by light, heat, air, and during preparation - mild or subclinical deficiencies of vitamin A, B6, C, folate may affect those that 1) in certain age groups - - infants, adolescents, pregnant and lactating women, and older people 2) smoke, abuse alcohol, or use longterm meds 3) chronically ill, physically or psychologically 4) are poor or finicky eaters - chronic dieters, strict vegetarians, and food faddists - will never be a substitute for good nutrition and healthy lifestyle practices - classified as: water soluble (vitamin C and B-complex) – absorbed through intestinal wall directly into bloodstream - deficiency symptoms are apt to develop quickly when intake is inadequate - toxicities are not likely fat soluble (vitamins A, D, E, K) – absorbed with fat into lymphatic circulation - secondary deficiencies can occur anytime fat digestion or absorption is altered - body stores excesses mostly in the liver and adipose tissue - daily intake is not imperative
b. Minerals – inorganic elements found in all body fluids and tissues in the form of salts or combined with organic compounds - function to provide structure within body, help to regulate body processes - not broken down or rearranged in the body, but are contained in ash that remains after digestion c.
Water – accounts for between 50 – 60% of adult’s total weight - infants have proportionately more water accounting for
body weight - about two-thirds of body’s water is contained within cells (intracellular fluid), with the remainder including all other body fluids such as plasma and interstitial fluid (extracellular fluid) - provides medium necessary for all chemical reactions, participates in many reactions and is not stored in body - acts as solvent that dissolves many solutes, aiding in digestion, absorption, circulation, and excretion - helps regulate body temperature - acts as lubricant needed for mucous secretions and for movement between joints - produced through metabolism of carbohydrates, protein, and fat - leaves through urine, feces, expired air, and perspiration - balance may be seriously affected when intake or output is altered E.
CHOOSING AN ADEQUATE DIET - nutritional concerns focus more on problems of overnutrition - promoting health through proper nutrition has been made easier by labeling regulations that provide specific information 1.
Food Groups - grain and cereal group are at the base of the pyramid followed by: fruit and vegetable group meat and dairy groups fat, oil, and sweets group at the peak - pyramid emphasizes grain and cereal group as basic food in diet with less desirable groups playing a much smaller nutritional role - all are required, in proper proportions, for healthy diet
2. Recommended Dietary Allowance – represents avg daily amts of nutrients considered to be adequate to meet known nutritional needs of practically all healthy people - safety factor built in to account for individual variations - some people may not be able to meet individual requirements - possible to eat less than RDA and still avoid deficiencies 3.
Guidelines from American Dietary Association Aim for Fitness – aim for a healthy weight; be physically active each
day Build a Health Base – let pyramid guide food choices; choose variety of grains daily, especially whole grains; choose variety of fruits and vegetables daily; keep food safe to eat Choose Sensibly – choose diet low in saturated fat and cholesterol and moderate in total fat; choose beverages and food that limit intake of sugars; choose and prepare food with less salt; drink alcohol in moderation
II.
FACTORS AFFECTING NUTRITION
- patterns and habits may have greater impact on overall food intake - habits are product of many evolving variables, such as physical factors (geographic location, income), physiologic factors (health, hunger), and psychosocial factors (culture, religion) - conservative traditional influences, like culture, geographic region, and religion, have a stabilizing effect on habits A.
DEVELOPMENTAL CONSIDERATIONS - nutrient needs change in relation to growth, development, activity, and age-related changes in metabolism and body composition - periods of intense growth and development cause an increase in nutrient needs - nutrient needs stabilize during adulthood, although older people may need more or less of some nutrients - consistency of food, eating patterns, and significance of food change with physical and psychosocial development 1.
Infants – birth to 1 yr is most rapid period of growth - birth weight doubles in 4 – 6 mos. and triples by 1 yr - length increases 50%
- nutritional needs per unit of body weight are greater than at any other time in the life cycle - cow’s milk is not recommended for infants under 1 yr - solid foods are not introduced until 6 mos. because solid foods given too early may trigger allergic reactions - iron fortified foods are recommended 2. Toddlers / Preschoolers – can feed themselves, verbalize food likes and dislikes and occasionally use food to manipulate parents - appetite dramatically decreases and becomes erratic 3.
School Aged – nutritional implications focus on health promotion - needs to be balanced with foods of high nutritional value - appetite improves but still may be irregular
4. Adolescents – period of rapid physical, emotional, social and sexual maturation - needs, especially for calories, protein, calcium, and iron, increase to support growth anorexia nervosa – eating disorder characterized by extreme weight loss, muscle wasting, arrested sexual development, refusal to eat, and bizarre eating habits bulimia – eating disorder characterized by gorging followed by purging with self-induced vomiting, diuretics, and laxatives - nutritional needs may be harder to meet because fewer meals are eaten at home, peer influence and busy schedules have an impact 5.
Adults – needs level off, fewer calories are required
6. Pregnant and Lactating Women – needs increase to support growth and maintain maternal homeostasis, particularly during 2nd and 3rd trimester - key nutrient needs include protein, calories, iron, folic acid, calcium, and iodine 7.
Older Adults – caloric needs of body decrease - foods difficult to chew may need to eliminated, whereas an increase in fiber and fluid intake can relieve constipation - nutrient intake, digestion, absorption, metabolism, or excretion may be altered because of physiologic changes
B.
SEX
- men differ from women in nutrient requirements due to differences in body composition and reproductive function - larger muscle mass translates into higher caloric and protein requirements - women have proportionately more adipose tissue - women of childbearing age have higher iron requirements related to menstruation C.
STATE
HEALTH - alteration in nutrient requirements that results from illness and trauma varies with intensity and duration of the stress - trauma, like major surgery, burns, and crush injuries, is followed by hormonal changes that profoundly affect the body’s use of nutrients - to preserve or replenish body nutrient stores and to promote healing and recovery, requirements increase dramatically - chronic disorders, like diabetes, renal disease, hypertension, heart disease, GI disorders, and cancer, can alter nutrient requirements by influencing nutrient intake, digestion, absorption, metabolism, utilization, or excretion OF
D.
ALCOHOL ABUSE - alters body’s use of nutrients and interferes with normal nutrient absorption - requirements increase as efficiency of absorption decreases - need for B vitamins increases because they are used to metabolize alcohol - impairs nutrient storage, increases nutrient catabolism, and increases nutrient excretion E.
MEDICATIONS - absorption may be altered by drugs that: • change the pH of GI tract • increase GI motility • damage intestinal mucosa • bind with nutrients rendering them unavailable - metabolism can be altered by drugs that: • act as nutrient antagonists • alter enzyme systems that metabolize nutrients • alter nutrient degradation - some drugs alter renal reabsorption of nutrients and increase or decrease nutrient excretion
F.
MEGADOSES OF NUTRIENT SUPPLEMENTS - excess of one nutrient can lead to a deficiency (or increase the requirement) of another, especially if one is absorbed preferentially
III.
OBJECTIVE ASSESSMENT
A.
DIETARY DATA - after a screening tool identifies a patient at risk, such as in older adults, it is imperative that a nutritional assessment be completed as a follow-up 1. 24-Hour Recall Method – easiest way to collect dietary data, 24-hour recall of all food and beverages patient normally consumes during an average day - includes patient’s usual portion sizes, meal and snack patterns, meal timing, and location where food is eaten - information may not be reliable 2. Food Diaries - frequency questionnaires or diaries may provide a better overall picture of intake because patient records all food and beverages consumed in a specified period, usually 3 – 7 days 3. Risk Factors – Disease, Eating poorly, Tooth loss/mouth pain, Economic hardship, Reduced social contact, Multiple medicines, Involuntary weight loss/gain, Needs assistance in self-care, Elder years above age 80 B.
MEDICAL AND SOCIOECONOMIC DATA - medical, social, economic, cultural and psychological factors require evaluation for impact on nutritional requirements C.
ANTHROPOMETRIC DATA anthropometric – used to determine body dimensions - used to assess growth rate; can give indirect measurements of body protein and fat stores - standardized equipment and procedures must be used, data must be compared with appropriate reference standards for patient’s age and sex - height and weight, most common measurements, are obtained when patient is admitted to facility and periodically thereafter or assessed in home - weight patient on same scale at same time of day - because actual weight may be increased if patient has edema, hydration status must be
considered - self-reported weight may be recorded when actual weight is unobtainable - - highly inaccurate and must be noted - actual weight is recorded as soon as feasibly possible - additional measurements include triceps skin-fold measurements, measure of subcutaneous fat stores, midarm circumference, measure of both skeletal muscle mass and fat stores D.
CLINICAL DATA: SIGNS AND SYMPTOMS OF MALNUTRITION - signs and symptoms of altered nutrition usually do not appear until condition is advanced - further investigation is necessary to determine whether abnormal findings are actually caused by nutritional deficiency, are possibly related to a nutritional deficiency, or are unrelated to nutritional status E.
BIOCHEMICAL DATA - lab test, which measure blood and urine levels of nutrients or biochemical functions that depend on adequate supply of nutrients, can objectively detect problems in early stages - most routine biochemical tests measure protein status, body vitamin, mineral and trace element status hemoglobin – oxygen carrying protein of red blood cells hematocrit – volume of red blood cells packed by centrifugation in given volume of blood are measures of plasma protein that also reflect person’s iron status
PRINCIPLES
OF
NUTRITION
nutrition – study of nutrients and how they are handled by the body as well as the impact of human behavior and environment on the process of nourishment nutrients – specific biochemical substances used by body for growth, development, activity, reproduction, lactation, health maintenance, and recovery from illness or injury - needs change throughout the life cycle in response to changes in body size, activity, growth, development, and state of health - considered essential because they either are not synthesized in the body or are made in insufficient amts. - - must be provided in diet or through supplements Classes:
3 – supply energy (carbohydrates, protein, lipids) 3 – regulate body processes (vitamins, minerals, water)
II.
DEFINITION
A.
ENERGY BALANCE - energy is derived or obtained from foods consumed - only carbohydrates, protein, and fat provide energy
OF
ENERGY
AS
RELATED
TO
NUTRITION
calories – energy in the diet measured in the form of kilocalories - energy in the body is used to carry on any kind of activity whether voluntary or involuntary - total daily energy expenditure is the sum of all calories used to perform physical activity, maintain basal metabolism, and digest, absorb, and metabolize food - if daily energy intake is equal to total daily energy expenditure, weight will remain stable - if energy intake is less than energy expended, weight will decrease - if energy intake exceeds energy expenditure, weight will increase B.
METABOLIC REQUIREMENTS basal metabolism – amt of energy required to carry on the involuntary activities of the body at rest, such as maintaining body temperature and muscle tone, producing and releasing secretions, propelling food through the gastrointestinal (GI) tract, inflating the lungs, and contracting the heart muscle - as amt of energy used on physical activity declines, proportion of calories used for basal metabolism increases - men have higher basal metabolic rate (BMR) than women because of their larger muscle mass BMR = 1 cal/kg of body weight per hour for men BMR = 0.9 cal/kg of body weight per hour for women
- factors that increase BMR include growth, infections, fever, emotional tension, extreme environmental temperatures, and elevated levels of certain hormones, especially epinephrine and thyroid hormones - factors that decrease BMR include aging, prolonged fasting, and sleep C.
SPECIFIC DYNAMIC ACTION (SDA) - ideal body weight (IBW) or health body weight is an estimate of optimal weight for optimal health Rule-of-Thumb (ROT) - determines ideal weight based on height Females: 100 lbs (for height of 5’) + 5 lbs for each additional inch over 5’ Males: 106 lbs (for height of 5’) + 6 lbs for each additional inch over 5’ (add or deduct 10% from this figure based on body frame size) Body Mass Index (BMI) – ratio of height to weight, providing a more accurate reflection of total body fat stores in general population Kilograms and Meters: Weight in Kilograms (2.2 lb = 1 kg)
Pounds and Inches: Weight in Pounds x
704.5 Height2 in meters (39.37 in = 1 m)
Height in Inches
- provides an estimation of relative risk factors for diseases such as heart disease, diabetes, and hypertension - may not be accurate for people such as athletes, with a large muscle mass, or people with edema - BMI of 25 is considered overweight, 30 or greater indicates obesity Methods of Calculating Calorie Requirements: 1. Resting Energy Equivalent (REE) – amt of calories necessary to maintain body at rest Male Ex.: 65 kg x 1 cal/kg x 24 hr = 1560 cal/day Female Ex.: 65 kg x 0.9 cal/kg x 24 hr = 1404 cal/day - determine calories needed for specific activity level - REE is multiplied by one of the following: light activity REE x 0.55 – 0.65 moderate REE x 0.65 – 0.7 heavy 1.0
REE x 0.75 –
Male Ex.: 1560 x 0.55 = 858 calories Female Ex.: 1404 x 0.55 = 772 calories - total REE and calories needed based on activity level Male Ex.: 1560 + 858 = 2418 calories Female Ex.: 1404 + 772 = 2176 calories D.
CLASSES OF NUTRIENTS 1. Carbohydrates – known as sugars and starches, are organic compounds composed of carbon, hydrogen, and oxygen - only animal source of carbohydrate in the diet is lactose, or “milk sugar” - relatively easy to produce and store, most abundant and least expensive course of calories in diet - more easily and quickly digested than protein and fat - converted to glucose for transport through the blood or for use as energy - cells oxidize (burn) glucose to provide energy, carbon dioxide, and water - depending on person’s state of energy balance, the period between when carbohydrate is consumed and when it is used for energy may vary from minute to months or longer - when supply of glucose exceeds what is needed for energy and for maintaining serum levels, it is stored - when glycogen stores are adequate, body converts excess glucose to fat and stores it as triglycerides in adipose tissue Classifications: simple sugars (monosaccharides and disaccharides) complex sugars (polysaccharides) recommended dietary allowance (RDA) – recommendations for average daily amts that healthy population groups should consume over time ketosis – abnormal accumulation of ketone bodies that is frequently associated with acidosis 2.
Protein – vital component of every living cell - classified as essential because they cannot be synthesized in the
body - remaining amino acids are no less important but because the body can make them if a
supply of nitrogen is available, they are termed nonessential - excess amino acids are converted to fatty acids, ketone bodies, or glucose and are stored or used as metabolic fuel - required for formation of all body structures, including genes, enzymes, muscle, bone matrix, and hemoglobin - RDA for adults is 0.8 g/kg of desirable body weight, or about 56 g for avg. woman and 63 g for avg. man - stress of illness, surgery, or prolonged periods of time on simple IV without oral intake places patients at risk for developing protein-calorie malnutrition (PCM), resulting in weakness, poor wound healing, mental apathy, and edema catabolism – tissues continuously being broken down anabolism – tissues continuously being replaced - when both are occurring at the same rate, the body is in a state of neutral nitrogen balance - positive nitrogen balance occurs when nitrogen intake is greater than excretion (during periods of growth, pregnancy, lactation, and recovery from illness) - negative nitrogen balance, an undesirable state that occurs in situations such as starvation and catabolism that immediately follows surgery, illness, trauma, and stress, indicates that more nitrogen is being excreted than consumed 3.
Fats / Lipids – insoluble in water and, therefore, insoluble in blood - lipids in the diet are in the form of triglycerides, the predominant form of fat in food and major storage form of fat in the body - difference in degree of saturation depends on the amt of hydrogen in fat molecules - saturated fats tend to raise serum cholesterol levels, whereas unsaturated fats lower serum cholesterol levels trans fat – partially hydrogenate liquid oils, they become more solid and more stable - raises serum cholesterol cholesterol – fatlike substance found only in animal products
- need not be provided in the diet because the body synthesizes about twice as much cholesterol as most people eat - important component of cell membranes, especially abundant in brain and nerve cells - used to synthesize bile acids and is precursor of steroid hormones and vitamin D - to help lower serum cholesterol levels, eat less total fat – especially saturated and trans fat – eat more unsaturated fat, and increase fiber intake, which increases fecal excretion 4.
Regulatory Nutrients a. Vitamins – organic compounds needed by the body in small
amounts - active in form of coenzymes together with enzymes, facilitate thousands of chemical reactions in the body - needed for metabolism of carbohydrates, protein, and fat - may be destroyed by light, heat, air, and during preparation - mild or subclinical deficiencies of vitamin A, B6, C, folate may affect those that 1) in certain age groups - - infants, adolescents, pregnant and lactating women, and older people 2) smoke, abuse alcohol, or use longterm meds 3) chronically ill, physically or psychologically 4) are poor or finicky eaters - chronic dieters, strict vegetarians, and food faddists - will never be a substitute for good nutrition and healthy lifestyle practices - classified as: water soluble (vitamin C and B-complex) – absorbed through intestinal wall directly into bloodstream - deficiency symptoms are apt to develop quickly when intake is inadequate - toxicities are not likely fat soluble (vitamins A, D, E, K) – absorbed with fat into lymphatic circulation - secondary deficiencies can occur anytime fat digestion or absorption is altered - body stores excesses mostly in the liver and adipose tissue - daily intake is not imperative
b. Minerals – inorganic elements found in all body fluids and tissues in the form of salts or combined with organic compounds - function to provide structure within body, help to regulate body processes - not broken down or rearranged in the body, but are contained in ash that remains after digestion c.
Water – accounts for between 50 – 60% of adult’s total weight - infants have proportionately more water accounting for
body weight - about two-thirds of body’s water is contained within cells (intracellular fluid), with the remainder including all other body fluids such as plasma and interstitial fluid (extracellular fluid) - provides medium necessary for all chemical reactions, participates in many reactions and is not stored in body - acts as solvent that dissolves many solutes, aiding in digestion, absorption, circulation, and excretion - helps regulate body temperature - acts as lubricant needed for mucous secretions and for movement between joints - produced through metabolism of carbohydrates, protein, and fat - leaves through urine, feces, expired air, and perspiration - balance may be seriously affected when intake or output is altered E.
CHOOSING AN ADEQUATE DIET - nutritional concerns focus more on problems of overnutrition - promoting health through proper nutrition has been made easier by labeling regulations that provide specific information 1.
Food Groups - grain and cereal group are at the base of the pyramid followed by: fruit and vegetable group meat and dairy groups fat, oil, and sweets group at the peak - pyramid emphasizes grain and cereal group as basic food in diet with less desirable groups playing a much smaller nutritional role - all are required, in proper proportions, for healthy diet
2. Recommended Dietary Allowance – represents avg daily amts of nutrients considered to be adequate to meet known nutritional needs of practically all healthy people - safety factor built in to account for individual variations - some people may not be able to meet individual requirements - possible to eat less than RDA and still avoid deficiencies 3.
Guidelines from American Dietary Association Aim for Fitness – aim for a healthy weight; be physically active each
day Build a Health Base – let pyramid guide food choices; choose variety of grains daily, especially whole grains; choose variety of fruits and vegetables daily; keep food safe to eat Choose Sensibly – choose diet low in saturated fat and cholesterol and moderate in total fat; choose beverages and food that limit intake of sugars; choose and prepare food with less salt; drink alcohol in moderation
II.
FACTORS AFFECTING NUTRITION
- patterns and habits may have greater impact on overall food intake - habits are product of many evolving variables, such as physical factors (geographic location, income), physiologic factors (health, hunger), and psychosocial factors (culture, religion) - conservative traditional influences, like culture, geographic region, and religion, have a stabilizing effect on habits A.
DEVELOPMENTAL CONSIDERATIONS - nutrient needs change in relation to growth, development, activity, and age-related changes in metabolism and body composition - periods of intense growth and development cause an increase in nutrient needs - nutrient needs stabilize during adulthood, although older people may need more or less of some nutrients - consistency of food, eating patterns, and significance of food change with physical and psychosocial development 1.
Infants – birth to 1 yr is most rapid period of growth - birth weight doubles in 4 – 6 mos. and triples by 1 yr - length increases 50%
- nutritional needs per unit of body weight are greater than at any other time in the life cycle - cow’s milk is not recommended for infants under 1 yr - solid foods are not introduced until 6 mos. because solid foods given too early may trigger allergic reactions - iron fortified foods are recommended 2. Toddlers / Preschoolers – can feed themselves, verbalize food likes and dislikes and occasionally use food to manipulate parents - appetite dramatically decreases and becomes erratic 3.
School Aged – nutritional implications focus on health promotion - needs to be balanced with foods of high nutritional value - appetite improves but still may be irregular
4. Adolescents – period of rapid physical, emotional, social and sexual maturation - needs, especially for calories, protein, calcium, and iron, increase to support growth anorexia nervosa – eating disorder characterized by extreme weight loss, muscle wasting, arrested sexual development, refusal to eat, and bizarre eating habits bulimia – eating disorder characterized by gorging followed by purging with self-induced vomiting, diuretics, and laxatives - nutritional needs may be harder to meet because fewer meals are eaten at home, peer influence and busy schedules have an impact 5.
Adults – needs level off, fewer calories are required
6. Pregnant and Lactating Women – needs increase to support growth and maintain maternal homeostasis, particularly during 2nd and 3rd trimester - key nutrient needs include protein, calories, iron, folic acid, calcium, and iodine 7.
Older Adults – caloric needs of body decrease - foods difficult to chew may need to eliminated, whereas an increase in fiber and fluid intake can relieve constipation - nutrient intake, digestion, absorption, metabolism, or excretion may be altered because of physiologic changes
B.
SEX
- men differ from women in nutrient requirements due to differences in body composition and reproductive function - larger muscle mass translates into higher caloric and protein requirements - women have proportionately more adipose tissue - women of childbearing age have higher iron requirements related to menstruation C.
STATE
HEALTH - alteration in nutrient requirements that results from illness and trauma varies with intensity and duration of the stress - trauma, like major surgery, burns, and crush injuries, is followed by hormonal changes that profoundly affect the body’s use of nutrients - to preserve or replenish body nutrient stores and to promote healing and recovery, requirements increase dramatically - chronic disorders, like diabetes, renal disease, hypertension, heart disease, GI disorders, and cancer, can alter nutrient requirements by influencing nutrient intake, digestion, absorption, metabolism, utilization, or excretion OF
D.
ALCOHOL ABUSE - alters body’s use of nutrients and interferes with normal nutrient absorption - requirements increase as efficiency of absorption decreases - need for B vitamins increases because they are used to metabolize alcohol - impairs nutrient storage, increases nutrient catabolism, and increases nutrient excretion E.
MEDICATIONS - absorption may be altered by drugs that: • change the pH of GI tract • increase GI motility • damage intestinal mucosa • bind with nutrients rendering them unavailable - metabolism can be altered by drugs that: • act as nutrient antagonists • alter enzyme systems that metabolize nutrients • alter nutrient degradation - some drugs alter renal reabsorption of nutrients and increase or decrease nutrient excretion
F.
MEGADOSES OF NUTRIENT SUPPLEMENTS - excess of one nutrient can lead to a deficiency (or increase the requirement) of another, especially if one is absorbed preferentially
III.
OBJECTIVE ASSESSMENT
A.
DIETARY DATA - after a screening tool identifies a patient at risk, such as in older adults, it is imperative that a nutritional assessment be completed as a follow-up 1. 24-Hour Recall Method – easiest way to collect dietary data, 24-hour recall of all food and beverages patient normally consumes during an average day - includes patient’s usual portion sizes, meal and snack patterns, meal timing, and location where food is eaten - information may not be reliable 2. Food Diaries - frequency questionnaires or diaries may provide a better overall picture of intake because patient records all food and beverages consumed in a specified period, usually 3 – 7 days 3. Risk Factors – Disease, Eating poorly, Tooth loss/mouth pain, Economic hardship, Reduced social contact, Multiple medicines, Involuntary weight loss/gain, Needs assistance in self-care, Elder years above age 80 B.
MEDICAL AND SOCIOECONOMIC DATA - medical, social, economic, cultural and psychological factors require evaluation for impact on nutritional requirements C.
ANTHROPOMETRIC DATA anthropometric – used to determine body dimensions - used to assess growth rate; can give indirect measurements of body protein and fat stores - standardized equipment and procedures must be used, data must be compared with appropriate reference standards for patient’s age and sex - height and weight, most common measurements, are obtained when patient is admitted to facility and periodically thereafter or assessed in home - weight patient on same scale at same time of day - because actual weight may be increased if patient has edema, hydration status must be
considered - self-reported weight may be recorded when actual weight is unobtainable - - highly inaccurate and must be noted - actual weight is recorded as soon as feasibly possible - additional measurements include triceps skin-fold measurements, measure of subcutaneous fat stores, midarm circumference, measure of both skeletal muscle mass and fat stores D.
CLINICAL DATA: SIGNS AND SYMPTOMS OF MALNUTRITION - signs and symptoms of altered nutrition usually do not appear until condition is advanced - further investigation is necessary to determine whether abnormal findings are actually caused by nutritional deficiency, are possibly related to a nutritional deficiency, or are unrelated to nutritional status E.
BIOCHEMICAL DATA - lab test, which measure blood and urine levels of nutrients or biochemical functions that depend on adequate supply of nutrients, can objectively detect problems in early stages - most routine biochemical tests measure protein status, body vitamin, mineral and trace element status hemoglobin – oxygen carrying protein of red blood cells hematocrit – volume of red blood cells packed by centrifugation in given volume of blood are measures of plasma protein that also reflect person’s iron status
