Comprehensive Nutrition & Nutritional Support Notes

Nutrition Fundamentals

• Nutrition = sum of processes by which an individual ingests and utilizes nutrients
• Spectrum of nutritional status
  • Undernutrition: intake < metabolic needs ⇒ energy, protein, micronutrient deficits
  • Normal (euntrition): intake ≈ needs
  • Over-nutrition: intake > needs ⇒ overweight, obesity, hypervitaminosis, etc.
• Balanced diet must supply
  • Macronutrients: carbohydrates, fats (lipids), proteins
  • Micronutrients: vitamins, minerals, electrolytes
  • Water (critical solvent & transport medium)
• Estimating daily caloric need
  • Simple method: kilocalories per kilogram
  • Average adult requirement ≈ 20\text{–}35\;\text{kcal}\,/\,\text{kg}\,/\,\text{day}

Macronutrients: Carbohydrates

• Primary (chief) source of body fuel ("protein-sparing" role)
• Energy yield: 4\;\text{kcal/g}
• Recommended daily share: 45\%\text{–}65\% of total calories
• Fiber goal: 14\;\text{g} per 1000\;\text{kcal} consumed
• Classification
  • Simple carbohydrates
  • Monosaccharides: glucose, fructose (also galactose)
  • Disaccharides: sucrose, maltose, lactose
  • Complex carbohydrates
  • Polysaccharides (starches) in cereal grains, potatoes, legumes

Macronutrients: Fats (Lipids)

• Major concentrated energy source
• Energy yield: 9\;\text{kcal/g} ( > 2× carbohydrate/ protein)
• Storage: adipose tissue & visceral (abdominal) cavity
• Functions
  • Vehicle for fat-soluble vitamins & essential fatty acids
  • Organ protection, thermoregulation, satiety, cell membrane integrity
• Recommended intake: 20\%\text{–}35\% total calories
• Quality spectrum
  • Potentially harmful: saturated fatty acids, trans-fatty acids
  • Healthier: monounsaturated & polyunsaturated fats
  • “Heart-healthy” focus: polyunsaturated omega-3 FAs (e.g., EPA, DHA)

Macronutrients: Proteins

• Functions: tissue growth/repair/maintenance, enzymes, hormones, fluid balance, acid–base balance, immune function, energy
• Energy yield: 4\;\text{kcal/g}
• Daily caloric contribution: 10\%\text{–}35\%
• Structural unit = amino acid
  • Body synthesises non-essential AAs
  • Nine essential AAs must come from diet
• Protein quality
  • Complete (high-biologic value): eggs, fish, meats, milk/milk products, poultry ⇒ contain all essential AAs in adequate amounts
  • Incomplete: grains, legumes, nuts, seeds ⇒ limiting AA(s)

Micronutrients: Vitamins

• Organic compounds needed in minute quantities for normal metabolism; act mainly as coenzymes
• Categories
  • Water-soluble: vitamin C, B-complex (B₁, B₂, B₃, B₅, B₆, B₇, B₉, B₁₂)
  • Fat-soluble: vitamins A, D, E, K

Minerals

• Inorganic elements; constitute ≈4\% of body weight
• Roles: tissue building, fluid & electrolyte balance, nerve conduction, muscle contraction, cofactors in enzyme systems
• Major (macro) minerals
  • Calcium, Chloride, Magnesium, Phosphorus, Potassium, Sodium, Sulfur
• Trace (micro) elements
  • Chromium, Copper, Fluoride, Iodine, Iron, Manganese, Molybdenum, Selenium, Zinc

Special Diets & Cultural Competence

• Vegetarian spectrum
  • Vegetarian (semi-, pesco-, pollo-): excludes red meat
  • Lacto-ovo: plants + dairy + eggs
  • Vegan: plants only; high risk for vitamin B₁₂ (cobalamin) deficiency ⇒ megaloblastic anaemia & neuropathy
• Keys to vegetarian adequacy: complementary proteins, vitamin B₁₂, iron, calcium, vitamin D, omega-3 FAs
• Iron-rich foods (selected)
  • Fortified cereals (farina, oatmeal, ready-to-eat cereal)
  • Animal sources: beef/chicken/turkey/pork liver, clams, oysters
  • Plant/alternate: soybeans
• Culturally competent care
  • Ascertain traditional foods, religious laws (e.g., kosher, halal)
  • Teach modifications to whole family; avoid stereotyping

Malnutrition: Definitions & Types

• Malnutrition = deficit, excess, or imbalance of essential nutrients
  • Undernutrition: inadequate intake, absorption, or utilization of nutrients
  • Overnutrition: excess nutrient/energy intake leading to obesity, hyperlipidemia, etc.
• Etiologic categories (ASPEN)
  • Starvation-related (primary PCM): chronic starvation w/o inflammation (e.g., anorexia nervosa)
  • Chronic disease–related: mild–moderate inflammation (organ failure, cancer, RA, obesity)
  • Acute disease/injury–related: marked inflammation (major infection, burns, trauma, surgery)
• Contributing factors
  • Socioeconomic: food insecurity, “heat-or-eat” dilemma, limited support programs
  • Physical illnesses: GI disorders, malabsorption, surgery, hospitalization
  • Psychosocial: fear, depression
  • Drug–nutrient & herb–drug interactions

Pathophysiology of Starvation

• Stage 1 (0–18 h): use liver & muscle glycogen → glucose
• Stage 2 (≥18 h): glycogen depleted ⇒ gluconeogenesis from skeletal protein → negative nitrogen balance
• Stage 3 (≈day 5–9): lipolysis ↑, fat supplies up to 97\% of calories; protein conserved
• Stage 4 (weeks 4–6): fat stores exhausted ⇒ visceral & somatic proteins catabolised
  • ↓ liver protein synthesis, ↓ oncotic pressure ⇒ third spacing/edema (albumin leak)
  • Na⁺/K⁺ pump failure, fatty infiltration of liver
• Without re-feeding ⇒ multi-organ failure & death

Clinical Manifestations of Malnutrition

• Spectrum: mild weight loss → emaciation → death
• Systems affected
  • Skin, hair, nails: dryness, brittle, thin, spoon nails
  • Oral cavity: glossitis, stomatitis
  • Musculoskeletal: wasting/weakness
  • CNS: confusion, irritability, paresthesias
  • Immune: infection susceptibility ↑
  • Hematologic: anemia (↓RBC, ↓Hgb), lymphopenia

Diagnostic & Assessment Tools

• History: 7-day food recall, weight changes, comorbidities, meds
• Anthropometrics: height, weight, BMI, mid-arm circumference, skinfold thickness
• Screening instruments: Mini-Nutritional Assessment (MNA), Minimum Data Set (MDS), OASIS
• Labs
  • Serum albumin (long-term), pre-albumin (short-term), C-reactive protein (inflammation)
  • Electrolytes, CBC, lymphocyte count
• Functional: hand-grip dynamometry

Nursing Management of Malnutrition

• Diagnoses: impaired nutrition, intake, fluid imbalance, tissue integrity risk
• Goals
  • Achieve target weight & calorie intake
  • Avoid complications (refeeding, infection, skin breakdown)
• Interventions
  • High-calorie, high-protein meals & snacks; multiple small feedings
  • Calorie counts, diet diaries, supplements, appetite stimulants
  • Consult dietitian; educate on MyPlate, food labels
  • Monitor I&O, daily weights, labs; plan for discharge

Gerontologic Considerations

• Age-related changes: dentition loss, decreased taste/smell, dysphagia, slowed GI motility, ↓ vision/hearing, limited finances
• Increased vulnerability to malnutrition & EN/PN complications: fluid–electrolyte shifts, glucose intolerance, aspiration risk

Enteral Nutrition (EN)

• AKA tube feeding; delivery of nutritionally complete liquefied formula via GI tube
• Tube routes: stomach (gastric), duodenum, jejunum
• Indications: anorexia, orofacial fractures, head/neck cancer, neurologic disorders, burns, critical illness, chemo/radiation
• Advantages vs PN: physiologic, safer, cheaper, maintains gut integrity
• Formulas: standard (1–2 kcal/mL), disease-specific (DM, renal, hepatic, pulmonary)
• Delivery modalities
  • Continuous pump, cyclic, bolus gravity, bolus syringe
• Tube types
  • Nasogastric/nasointestinal (polyurethane/silicone): easy but may clog, dislodge, knot
  • Gastrostomy (PEG) or jejunostomy: long-term; require functional GI tract; placed surgically, radiologically, endoscopically
  • PEG: endoscopic placement; feed within 4\text{–}24\;\text{h} once bowel sounds present

Administration & Safety

• ASPIRATION is major risk
• Position: HOB 30^{\circ}\text{–}45^{\circ} during & 30\text{–}60\;\text{min} post-feed
• Tube position verification
  • Gold standard: radiographic confirmation (X-ray)
  • Mark exit length; check pH, aspirate, observe each use/q8h continuous
• Residual volume: follow policy; consider promotility agents
• Tube patency: flush 30\;\text{mL} warm water pre/post feeds & meds; continuous feeds via pump with occlusion alarm
• Site care: daily assessment, manage bumper tension, dressings until healed, soap & water, skin barrier
• Misconnection prevention: tracing lines, unique hubs; wrong connection can cause death
• Monitoring
  • Weights, bowel sounds, I&O, capillary glucose, formula/change dates, tubing q24h
• Complications: vomiting, dehydration (calorie-dense formula), diarrhea, constipation, skin irritation, tube dislodgement

Parenteral Nutrition (PN)

• Intravenous delivery of nutrients for non-functional or inaccessible GI tract
• Goals: meet requirements, promote anabolism, tissue repair
• Indications: severe diarrhea/vomiting, GI obstruction, fistula, short bowel, severe malabsorption, intractable anorexia, complex surgery/trauma

Composition

• Base: dextrose + amino acids; customized electrolytes, vitamins, trace elements; IV fat emulsion (10%–30%) supplies up to 30\% calories
  • Dextrose: 100\text{–}150\;\text{g/day} ( 1\;\text{g}=3.4\;\text{kcal} )
  • Protein: 1\text{–}1.5\;\text{g/kg/day} (↑ in depletion)
• Pharmacist compounds under strict aseptic conditions; refrigerated until <30\;\text{min} before use; labelled with content & expiration

Routes

• Central PN: catheter tip in SVC (subclavian, jugular, or PICC); hypertonic (glucose 20\%\text{–}50\%); long-term
• Peripheral PN: peripheral line; less hypertonic (≤20\% glucose); short-term, lower calorie/protein needs, lower central-line risk

Complications

• Refeeding syndrome: fluid retention, electrolyte shifts; hallmark = hypophosphatemia
• Metabolic: renal dysfunction, essential FA deficiency, hyper/hypoglycemia, hyperlipidemia, liver dysfunction
• Catheter-related: air embolus, sepsis, dislodgement, thrombosis, phlebitis, hemorrhage, occlusion, pneumothorax, hemothorax, hydrothorax

Nursing Management

• Vital signs q4–8h; daily weight
• Capillary glucose q4–6h initially
• Strict infusion pump; chart volume infused vs ordered
• Labs: electrolytes, BUN, CBC, liver enzymes
• Dressing changes with sterile technique; assess site for local & systemic infection (redness, tenderness, exudate; fever, chills, N/V, malaise)
• Tubing & bag changed q24h; inspect solution for contamination
• X-ray for catheter placement & pulmonary changes
• Education for home PN: aseptic technique, bag mixing, line care, complication recognition, supplies procurement, discharge planning

Key Numerical & Formula Summary

• Daily calories: 20\text{–}35\;\text{kcal/kg/day}
• Carbohydrate energy: 4\;\text{kcal/g}
• Fat energy: 9\;\text{kcal/g} (recommended 20\%\text{–}35\% calories)
• Protein energy: 4\;\text{kcal/g} (target 10\%\text{–}35\% calories; 1\text{–}1.5\;\text{g/kg/day} in PN)
• Fiber: 14\;\text{g}/1000\;\text{kcal}
• Enteral formulas: 1\text{–}2\;\text{kcal/mL}
• Lipid emulsion PN: 10\% = 1\;\text{kcal/mL}; max 2.5\;\text{g/kg/day}
• Tube flush standard: 30\;\text{mL} warm water
• HOB elevation: 30^{\circ}\text{–}45^{\circ}