Essential Nutrients, Metabolism, and Clinical Dietetics

Nutrients and Their Functions

Nutrients are substances found in food that maintain health and provide the energy necessary to live.

• Carbohydrates: 55% (1g = 4 kcal)
• Proteins: 15%
• Lipids: 30% (1g = 9 kcal)

Calories and Metabolism

A calorie is the energy required to raise the temperature of 1 gram of water by 1°C. A kcal is the energy needed to raise the temperature of 1 liter of water by 1°C.

Metabolism refers to the bodily processes through which the body obtains the energy needed for life functions while producing waste products that must be eliminated to prevent health damage.

Energy Balance and BMI

Energy balance involves controlling food intake to ensure it is suitable for the individual. Anamnesis is used to assess weight changes:

• Normal: 20–25
• Overweight: 25–30
• Slightly Obese: 30–35
• Moderately Obese: 35–40
• Morbidly Obese: >40

Dietetics and Therapeutic Nutrition

Dietetics is the science that studies diets to maintain or recover health. A balanced diet must be adapted to the individual's physical activity.

Therapeutic Diets by Consistency

• Absolute Diet: Used before digestive surgery or blood analysis.
• Liquid Diet: Used in the postoperative period.
• Semi-soft Diet: Incorporates elements from the liquid diet.
• Soft Diet (Purees): Introduces solid foods with a very soft consistency.

Energy and Nutrient-Modified Diets

• Hypocaloric: To reduce weight in obese or overweight patients.
• Hypercaloric: Increases caloric load, especially carbohydrates and fats, for patients with anorexia.
• Hyperproteic: To recover protein deficiencies in patients with pressure ulcers, burns, or elderly patients.
• Hypoproteic: Reduces protein intake for patients with renal disease.
• Hypoglycemic: Reduces carbohydrates for patients with hyperglycemia.
• Hyposodic: Reduces salt intake for hypertensive patients.
• Hypocholesterolemic: Reduces cholesterol by increasing vegetable fats, oils, and fish.
• Astringent: Used during diarrhea to compact feces.
• Laxative: Used for constipation, emphasizing water, fiber, and physical exercise.

Enteral Feeding Techniques

Nasogastric Tube Feeding

A peristaltic pump regulates the flow of nutrients (measured in ml/h) from a bag prepared by the pharmacy department into the nasogastric tube.

Ostomy Feeding

Used for patients who cannot be fed via nasogastric tube. Methods include:

• Gastrostomy
• Duodenostomy
• Jejunostomy