--- module: 050-01 language: en chapter: 50 title: "Malnutrition, Micronutrients, Enteral and Parenteral Support, and Obesity Care" module_title: "Foundations" source_sha256: 308fe366bb1fe0edbe34a5b176f98c8ad346791691a4ae20579eed17016239a8 --- # Malnutrition, micronutrients, feeding support, and obesity ## Orientation ### Nutrition supplies energy, nutrients, water, electrolytes ### Food also carries cultural, social, psychological meaning ### Malnutrition has several mechanisms #### Deficient intake, catabolism, absorption, utilisation #### Excess adiposity with poor nutrient quality ### Body size misleads: obesity can hide muscle loss ### Assess mechanism, severity, function, refeeding, route ## Energy, protein, and adaptation ### Basal metabolism maintains gradients, turnover, repair ### Total expenditure adds activity, growth, illness ### No inert protein reserve #### Negative balance consumes muscle and organ protein ### Fasting: insulin falls, glucagon and stress hormones rise #### Glycogenolysis, lipolysis, gluconeogenesis, ketones #### Brain ketone use limits but does not stop protein loss ### Inflammatory catabolism despite feeding #### Not reversed until the disease is controlled #### Protein and mobilisation preserve function ## Recognising malnutrition ### Risks: poor intake, disease, poverty, high losses ### History: intake, duration, weight trajectory, access #### Weight change: tissue, fluid, or both ### Examine muscle, fat, oedema, mouth, skin, strength #### Ascites and oedema conceal weight loss ### Body mass index neither excludes nor measures ### Screening finds risk; diagnosis integrates #### Phenotype plus intake, malabsorption, inflammation ### No single blood test diagnoses malnutrition #### Albumin falls with inflammation, leak, dilution ## Protein-energy malnutrition ### Weakness, infection, poor healing, falls, hypothermia ### Acute illness: rapid muscle loss, stable weight ### Sarcopenia: low muscle strength and quantity ### Frailty: broader multisystem vulnerability ### Resistance exercise, protein, less fasting ### Improve meals before escalating route #### Supplements add to, not displace, preferred meals ### Dietitian calculates needs and checks delivery ### Avoid rigid calorie targets ## Micronutrient deficiencies ### Iron deficiency #### Search for bleeding, loss, intake, demand #### Ferritin rises with inflammation #### Intravenous iron for speed, intolerance, losses ### Folate and vitamin B twelve impair DNA synthesis #### B twelve: neuropathy, cord, cognitive, optic injury #### Folate alone lets neurological injury progress ### Thiamine for oxidative carbohydrate metabolism #### Wernicke: confusion, eye movements, ataxia #### Give before carbohydrate, never delay emergency glucose ### Vitamin C collagen, D bone, K coagulation ### A, E, zinc, copper, selenium: risk-directed tests ## Refeeding syndrome ### Insulin drives phosphate, potassium, magnesium into cells #### Thiamine demand rises, sodium and water retained #### Arrhythmia, heart failure, respiratory weakness, death ### Risk: low weight, minimal intake, alcohol, depletion ### Prevention before feeding #### Thiamine, multivitamin, electrolyte correction #### Start cautiously and increase progressively ### Monitor fluid, cardiac signs, electrolytes, kidneys ### Any route, including intravenous glucose ## Enteral nutrition ### Preferred when the gut works #### Supports mucosa, fewer line and metabolic harms ### Nasal tubes short term, ostomies longer term ### Confirm tube position by approved methods ### Head elevation, mouth care, flushing, medicines ### Gastric residual volume is an imperfect marker ### Diarrhoea usually from drugs, infection, rate ## Parenteral nutrition ### For a gut that cannot absorb enough #### Obstruction, short bowel, high-output fistula ### Central access allows concentrated solutions ### Dedicated aseptic line, daily review #### Catheter infection and thrombosis can be fatal ### Metabolic complications #### Hyperglycaemia, triglycerides, liver, gallbladder ### Transition to enteral or oral intake with a plan ## Obesity as chronic disease ### Biology, environment, sleep, medicines, genetics ### Adipose dysfunction drives many complications ### Assess broadly, speak respectfully, ask permission ### Aim for health and function, not a number ### Base: nutrition, activity, sleep, psychology ### Anti-obesity medicines need long-term strategy ### Metabolic surgery: durable loss, lifelong follow-up #### Rapid loss: gallstones and exposed sarcopenia