Nutrition Fundamentals
NUTRITION
WHAT IS NUTRITION?
Definition:
Nutrition: the study of food and its effects on the human body and health.
Metabolism: the process by which the body converts food into energy.
Adequate nutrition is essential for wellness.
NUTRITION CONT.
Nutrients:
Includes carbohydrates, proteins, and lipids.
Serve as building blocks for cells and tissues.
Macronutrients:
Supply energy measured in kilocalories.
Micronutrients:
Help manufacture, maintain, and repair cells.
Found in foods; undergo changes in the body through metabolism.
Metabolic Processes:
Anabolism: formation of larger molecules from smaller ones; essential for tissue repair as amino acids form proteins, requiring energy.
Catabolism: breakdown of larger molecules into smaller ones, which releases energy.
CARBOHYDRATES
Primary Energy Source:
Function as the main source of energy for the body.
Types of Carbohydrates:
Simple Carbohydrates (simple sugars):
Monosaccharides: one unit of sugar.
Disaccharides: two saccharides.
Complex Carbohydrates:
Polysaccharides: long chains of sugar units, dietary fiber is a type of polysaccharide.
CARBOHYDRATE FUNCTIONS:
Provides energy for muscle & organ function; easily and quickly digestible.
Acts as a fuel for short-term muscle activity and provides almost all energy to the brain.
Stores glucose in the liver/skeletal muscle tissue as glycogen, which is converted to glucose to meet energy needs through glycogenolysis.
Increases feelings of fullness and satisfaction.
Improves absorption of sodium and excretion of calcium.
Spares protein: In malnourished patients, low glycogen stores lead to the breakdown of body protein and lipids for energy, through a process called gluconeogenesis.
When proteins are used for energy, they cannot perform their functions.
Ketones: fat converts directly into an alternative fuel for cells, raising blood acidity and potentially leading to balance issues; significant in diabetic contexts where cells cannot utilize glucose for energy.
Insulin: a pancreatic hormone that promotes glucose movement into cells for energy usage.
PROTEINS
Definition:
Complex molecules made up of amino acids.
Amino Acids:
Essential Amino Acids: Must be obtained through diet as the body cannot produce them.
Nonessential Amino Acids: Can be synthesized in the body.
Complete Proteins: Contain all essential amino acids; typically derived from animal sources (e.g., meat, fish).
Incomplete Proteins: Lack one or more essential amino acids; common examples include nuts and grains; they can be combined to form a complete protein (e.g., peanut butter on whole grain bread).
PROTEIN METABOLISM & STORAGE:
Protein digestion begins in the stomach and primarily occurs in the small intestine through enzymatic breakdown into amino acids.
The body continuously breaks down and rebuilds proteins to maintain overall protein balance.
Nitrogen Balance:
Occurs when nitrogen intake equals nitrogen output.
Positive Nitrogen Balance: Nitrogen intake exceeds output; indicates excess amino acids available, promoting growth, pregnancy, and tissue repair.
Negative Nitrogen Balance: Nitrogen intake is less than output, typically occurring in cases of illness, injury (e.g., burns), or malnutrition.
PROTEIN FUNCTION:
Tissue Binding: Essential for the growth, maintenance, and repair of body cells and tissues.
Protein comprises the largest proportion of the body after water.
Metabolism: Enzymes are proteins that facilitate cellular reactions.
Immune Function: Lymphocytes and antibodies are composed of proteins.
Fluid Balance: Proteins attract water, regulating fluid balance.
Acid-Base Balance: Blood proteins act as buffers to maintain pH.
Secondary Energy Source: Proteins can be broken down to provide energy when fat and carbohydrate stores are depleted.
LIPIDS
Definition:
Organic compounds composed of carbon that are insoluble in water.
Types:
Fats: Solid at room temperature.
Oils: Liquid at room temperature.
Glycerides: True fats consisting of glycerol, fatty acids, and triglycerides.
Sterols: Lipids that do not consist of fatty acids, e.g., cholesterol, which is essential for cell membranes, production of steroid hormones, and metabolic functions.
Synthesized in the liver, found in animal-derived foods.
Phospholipids: Water-soluble lipids, involved in forming cell membranes.
TYPES OF FATS:
Monounsaturated Fats:
Sources: olives, olive oil, peanut oil, peanuts.
Effect: Lowers LDL (low-density lipoprotein) cholesterol levels and raises HDL (high-density lipoprotein).
Polyunsaturated Fats:
Sources: corn, soybean, fish, nuts, seeds.
Effect: Lowers LDL and raises HDL.
Saturated Fats:
Sources: whole milk, butter, cheese, ice cream, red meat, processed foods.
Effect: Raises both LDL and HDL cholesterol levels.
Trans-Fats:
Sources: margarines, deep-fried foods, chips, fast food.
Effect: Raises LDL cholesterol levels.
Dietary Cholesterol:
Sources: meats, eggs, dairy, organ meats, fish (from animals).
Effect: Raises cholesterol levels in the body.
LIPID FUNCTIONS:
Supplies essential nutrients, including essential fatty acids, and aids absorption of fat-soluble vitamins.
Acts as an energy source; the body burns fat for energy during light activity when glycogen stores are depleted; carbohydrates are primarily used during strenuous activity.
Provides flavor and promotes satiety; fats contribute to food's creamy texture and taste.
Body fat is crucial for insulation, protecting vital organs, aiding in thermoregulation, and facilitating accurate nerve impulse transmission.
Cholesterol serves vital functions including being a cellular component, providing structural support, and being involved in the metabolism of steroid hormones.
MICRONUTRIENTS
Comprise vitamins and minerals required by the body in very small amounts.
Provide no energy directly but are critical for regulating a variety of body functions.
VITAMINS
Definition:
Vitamins are organic substances necessary for metabolism and for preventing deficiency diseases; important for building and maintaining body tissues, supporting the immune system, ensuring health vision, and are especially critical during periods like rapid growth, pregnancy/lactation, and healing processes.
Fat-Soluble Vitamins:
Vitamins A, D, E, and K, stored in the liver and fatty tissues.
Do not need to be consumed daily due to their storage capacity but can lead to toxicity if consumed in excess.
Water-Soluble Vitamins:
Vitamins C and B-complex; need to be consumed daily as they are regularly excreted via urine.
Toxicity is rare due to their lack of storage.
VITAMIN A
Functions:
Critical for night and color vision, cellular growth, maintaining healthy skin and mucous membranes, growth of skeletal and soft tissues, and reproduction.
Food Sources:
Fish liver, butter, cream, egg yolk, green leafy vegetables, fortified milk.
Effects of Deficiency:
Night blindness.
Toxicity Symptoms:
Gastrointestinal upset, headaches, blurred vision, fetal defects.
VITAMIN D
Functions:
Regulates blood calcium levels and controls the rate of calcium deposit and resorption in bones.
The inactive form, Cholecalciferol (D3), is converted by the liver to calcifediol and then activated by the kidneys to calcitriol which increases calcium absorption from the gastrointestinal tract, thus increasing blood calcium and phosphate levels and promoting bone health.
Food Sources:
Fish liver oil, fatty fish, fortified milk, exposure to sunlight.
Effects of Deficiency:
Can cause bone and muscle pain, weakness, softening of bones, and fractures (rickets).
Toxicity Symptoms:
Fatigue, weakness, loss of appetite, mental confusion, potential developmental issues in infants.
VITAMIN E
Functions:
Acts as an antioxidant that protects blood cells and muscle tissue cells from oxidative damage.
Food Sources:
Vegetable oils, nuts, milk, eggs, muscle meats, and green leafy vegetables.
Effects of Deficiency:
Hyporeflexia, ataxia (loss of full control of bodily movements), and anemia.
Toxicity Symptoms:
Insufficient blood clotting and impaired immune system function.
VITAMIN K
Functions:
Crucial for the synthesis of clotting factors and for bone development.
Food Sources:
Green leafy vegetables, liver.
Effects of Deficiency:
Can lead to increased bleeding.
Toxicity Symptoms:
Potential for jaundice and hemolytic anemia in infants.
CALCIUM
Functions:
Essential for bone and teeth formation, blood clotting, nerve conduction, muscle contraction, cellular metabolism, and heart action.
Food Sources:
Dairy products, sardines, green leafy vegetables, whole grains, egg yolks, nuts.
Effects of Deficiency:
Bone loss, tetany (muscle spasms), rickets (softening of bones), osteoporosis (weak fragile bones).
Toxicity Symptoms:
Possible kidney stones, constipation, and intestinal gas.
Normal Range:
$9 - 10.5 ext{ mg/dL}$
MAGNESIUM
Functions:
Aids in thyroid hormone secretion, maintains normal basal metabolic rate, activates enzymes for carbohydrate and protein metabolism, and is vital for nerve and muscle function as well as cardiac function.
Food Sources:
Whole grains, nuts, legumes, green leafy vegetables, lima beans, squash.
Effects of Deficiency:
Symptoms can include tremors, spasms, convulsions, weakness, and muscle pain.
Toxicity Symptoms:
May lead to weakness, nausea, malaise.
Normal Range:
$1.3 - 2.1 ext{ mEq/L}$
POTASSIUM
Functions:
Regulates intracellular fluid control, acid-base balance, nerve transmission, muscle contraction, glycogen formation, protein synthesis, blood pressure, and energy metabolism.
Food Sources:
Unprocessed foods including fruits, vegetables, potatoes, meats, avocados, milk, and shellfish.
Effects of Deficiency:
Can lead to muscle weakness (heart and respiratory), weak pulse, fatigue, and abdominal distention.
Toxicity Symptoms:
Cardiac dysrhythmias, cardiac arrest, weakness, abdominal cramps, diarrhea, anxiety.
Normal Range:
$3.5 - 5 ext{ mEq/L}$
SODIUM
Functions:
Essential for water balance, acid-base balance, muscle action, and nerve transmission, and can induce convulsions.
Food Sources:
Table salt, milk, eggs, baking soda, celery, and spinach.
Effects of Deficiency:
Dizziness, abdominal cramping, nausea, vomiting, diarrhea, tachycardia, convulsions, coma.
Toxicity Symptoms:
Results in thirst, fever, dry/sticky tongue and mucous membranes, restlessness, irritability, convulsions.
Normal Range:
$136 - 145 ext{ mEq/L}$
WATER
Comprises a significant percentage of body weight:
Approximately $55 - 65 ext{%}$ of total body weight in men; $50 - 55 ext{%}$ in women.
Functions:
Acts as a solvent for body processes, transports substances (oxygen, nutrients, metabolic wastes), helps in body structure, temperature regulation, lubrication, and acts as a catalyst.
ENERGY BALANCE CONCEPTS
Caloric Measurement:
Energy in nutrients is measured in calories.
Balance Requirement:
Calories “in” must equal calories burned to maintain energy balance.
Under-Nutrition & Obesity:
Too few calories/nutrients lead to undernourishment.
Excessive caloric intake can result in obesity.
ENERGY BALANCE CONCEPTS CONT.
Basal Metabolic Rate (BMR):
Refers to the amount of energy required at rest in a neutral environment.
Energy needed for vital organs such as the heart, liver, brain.
Total Energy Needs:
Includes calories replacing the ones used for BMR as well as additional calories for physical activity.
LIFESPAN CONSIDERATIONS:
Nutritional needs vary across different life stages, including:
Infancy
Childhood
Adolescence
Adulthood
Older Adults
Pregnancy
FACTORS THAT AFFECT NUTRITION
These factors include considerations for individuals from infancy to older age:
Developmental stages, knowledge of disease processes associated with deficiencies, and educational levels regarding nutrition.
LIFESTYLE CHOICES THAT AFFECT NUTRITION:
Dietary Patterns:
The types of foods consumed are equally important.
Variations such as vegetarianism, dieting can influence nutrition.
Work Environment:
Physically demanding jobs can lead to fatigue affecting food quality and quantity, alongside peer pressure.
Cooking Methods:
Cooking methods vary in nutrient retention; boiling can destroy water-soluble nutrients, while steaming preserves more.
Contraceptives:
Use can lower levels of Vitamin C and B.
Stress:
Certain foods can help reduce stress and cope with conditions such as depression and loneliness.
Tobacco Use:
Smokers utilize Vitamin C more rapidly.
Alcohol Consumption:
Linked to excessive caloric intake, potentially leading to obesity.
Caffeine:
Risk factors for dehydration and related health issues including heart disease and cancer.
FOOD GUIDES:
Food guides serve as practical tools to educate patients on dietary choices, including:
My Plate (https://www.choosemyplate.gov/), Diabetes food plate, Vegetarian options, and culture-specific diets like African heritage, Mediterranean, Latin American, and Traditional Asian.
DISEASE PROCESS & FUNCTIONAL LIMITATIONS:
Traumatic Injury:
Requires additional protein and Vitamin C for healing.
Long Term Insufficient Caloric Intake:
Results in weight loss and muscle wasting.
Alcoholism:
Associated with poor appetite and nutrient intake.
Cognitive Function Issues:
Developmental delays, mental illness, or head trauma can affect nutritional intake habits.
Ability to Obtain/Prepare Food:
Physical conditions (e.g., paralysis, hemiplegia) and social factors can impact one's ability to prepare and consume food.
Digestive Issues:
Problems with chewing and swallowing can necessitate dietary adjustments.
MEDICATIONS:
Various medications can decrease appetite, including but not limited to chemotherapy and radiation.
Certain drugs may alter metabolism and affect nutrient absorption.
SPECIAL DIETS
Regular Diet:
No restrictions.
NPO (Nothing by Mouth):
No food or fluids permitted.
Clear Liquid Diet:
Provides essential fluids to prevent dehydration, used in surgeries, GI disorders, or acute illness.
Examples include water, tea, broth, clear juices (no pulp), popsicles, carbonated beverages, and gelatin.
Full Liquid Diet:
Comprises all liquids and liquefied foods.
Examples include milk, shakes, yogurt, soups, pudding, cereals, juices with pulp.
High Fiber Diet:
Consists of whole grains, raw/dried fruit.
Blenderized Liquid (Pureed Diet):
Indicated for oral/facial surgery or chewing difficulties (e.g., mashed potatoes, avocado).
Soft (Low Fiber) Diet:
Transition from full liquid to regular diet.
Mechanical Soft Diet:
For those with chewing difficulties, featuring easier-to-chew items such as soft veggies, fruits, ground meat, and cheese.
Liquid Consistencies:
Definitions include thin, nectar, honey, and spoon-thick.
SCREENING FOR NUTRITIONAL PROBLEMS
Requires obtaining a detailed diet history using tools such as:
24-hour recall, food frequency questionnaire, and food records.
Subjective global assessments, weight history, dietary history, GI symptoms, energy levels, existing diseases, physical exams, and the Mini Nutritional Assessment can identify individuals at nutritional risk or in a state of malnutrition.
LAB VALUES THAT REFLECT NUTRITIONAL STATUS
Blood Glucose:
Indicator of readily available fuel for cellular energy.
Normal Range: 70-109 mg/dL.
Hypoglycemia: Below 50 mg/dL; can lead to weakness or coma due to insufficient fuel.
Hyperglycemia: Above 109 mg/dL when fasting or greater than 127 mg/dL randomly; connected to diabetes or endocrine issues due to insufficient insulin.
Symptoms include weakness, fatigue, excessive thirst, hunger, urination, ketosis, and peripheral neuropathy.
Albumin:
Low levels linked to malnutrition, malabsorption, liver disease, and protein loss from burns and wounds.
Normal Range: 3.4 – 4.8 g/dL.
Prealbumin:
Fluctuates daily; a better marker of acute changes compared to albumin; normal levels can be falsely low if fluid overloaded.
Normal Range: 12-42 mg/dL (from age 6 and up).
Creatinine:
A marker of renal function; increased levels indicate impaired kidney function or muscle loss.
Normal Ranges:
Female: 0.5-1 mg/dL; Male: 0.6-1.2 mg/dL.
Hemoglobin:
Low levels can suggest inadequate iron intake, chronic blood loss, etc.
Normal Range: 13.2 g/dL (M), 11.7-15.5 g/dL (F).
Hemoglobin A1C:
Normal: 4-5.6%; Pre-Diabetic: 5.7-6.4%; Diabetic: 6.5% or above.
CORONARY ARTERY DISEASE
Hypertension Management:
Maintain systolic pressure below 120 and diastolic below 80.
Recommendations include reducing red meat consumption, choosing lean meats, limiting trans and saturated fats, using red wine conservatively, increasing omega-3 fatty acids, avoiding frying food, opting for low-fat or non-fat dairy, and substituting spices for salt/butter.
DIABETES MANAGEMENT
Blood glucose should range between 70-109 mg/dL; fasting level should be less than 100 mg/dL.
Hemoglobin A1C should be kept within normal range.
Educate about dietary changes, promoting high fiber and low saturated fat, trans fat, and cholesterol diets to prevent coronary heart disease (CHD).
Note: Education on diabetes management is a nursing responsibility—not be delegated.
ALTERATIONS IN NUTRITION
Overweight/Obesity:
Resulting from intake of excess nutrients beyond metabolic demands; defined as:
Overweight: Body Mass Index (BMI) $>25$ but <$29.9$.
Obesity: BMI $>30$.
Underweight/Undernutrition:
Occurs due to insufficient intake of protein, fats, vitamins, and minerals; often consuming fewer calories than needed per activity levels and personal factors.
IDENTIFYING NUTRITIONAL IMBALANCES
Requires a complete physical examination covering:
General survey, alterations in vital signs, poor skin turgor, wound healing, abdominal condition (concave abdomen, ascites), muscle mass changes.
Laboratory results can indicate issues, such as changes in blood glucose, serum albumin, creatinine, and hemoglobin levels.
NURSING DIAGNOSIS EXAMPLES
Adult Failure to Thrive
Impaired Nutrition: Less than Body Requirements
Impaired Nutrition: More than Body Requirements
Risk for Imbalanced Nutrition: More than Body Requirements
Self-Care Deficit (Feeding) related to difficulties in chewing and swallowing.
HEALTHY PEOPLE 2030
Goal:
Improve health by promoting healthy eating and making nutritious foods accessible.
MANAGING NUTRITIONAL IMBALANCES: PLANNING
Identify the reason or etiology of an imbalance.
Examples of undernutrition include difficulties in chewing or swallowing, alcoholism, metabolic disorders, diabetes mellitus, gastrointestinal disorders, fevers, non-fitting dentures, and consuming only soft foods (which may lack fiber).
MANAGING NUTRITIONAL IMBALANCES: INTERVENTIONS
Education for clients and families concerning:
Vitamin and mineral supplementation.
Ways to obtain nutritious food on limited budgets (e.g. Meals on Wheels, home-delivered meals, congregate meals).
Addressing the nutritional needs of special clients:
Clients who are NPO; managing schedules with tests and medications carefully.
Older adults may require assistance in meal preparation and consumption.
For obesity:
Assist clients in calorie calculations and meal planning while promoting exercise and lifestyle changes ($30$ minutes of daily activity recommended).
Encourage weekly weight monitoring and suggest maintaining a food diary.
NASOGASTRIC TUBE
Placement Estimation:
Naso-gastric tube length estimated using the nose-earlobe-xiphisternum (NEX) measurement.
Confirmation Methods:
Chest X-ray (most accurate), pH testing of gastric aspirate (easy to perform);
Low pH (1-5.5) indicates placement in the stomach, pH 6 indicates placement, pH 7 or above may indicate in respiratory secretions.
MANAGING NUTRITIONAL IMBALANCES: INTERVENTIONS CONT.
For undernutrition:
Encourage clients to seek counseling if they have eating disorders.
Develop strategies to boost appetite.
Consider Enteral Nutrition or Parenteral Nutrition: monitor tube placement, laboratory values, and skin conditions.