5.1 Food Classes & Balanced Diet

1. Classes of Food

• Macronutrients: Required in large quantities; provide energy and building blocks.
  • Carbohydrates, Fats (Lipids), Proteins.
• Micronutrients: Required in smaller quantities; essential for metabolic processes.
  • Mineral Salts, Vitamins, Water.

1.1 Macronutrients: Functions

• Carbohydrates: Primary energy source, energy storage, protein sparing, prevents ketosis.
• Fats (Lipids): Concentrated energy source, insulation/protection, cell membrane component, hormone production, fat-soluble vitamin absorption, nerve function.
• Proteins: Building/repairing tissues, enzyme/hormone production, structural support, transport/storage, immune function, fluid/pH balance.

1.2 Micronutrients: Functions

Mineral Salts

• Calcium: Bones/teeth, muscle contraction, blood clotting.
• Iodine: Thyroid hormones (metabolism, growth).
• Iron: Hemoglobin (oxygen transport), energy metabolism.
• Sodium: Fluid balance, nerve impulses, muscle contraction.

1.2 Micronutrients: Functions (Continued)

Vitamins

• Vitamin A: Vision, immune function, skin.
• B Vitamins: Energy metabolism, RBC production, nerve function.
• Vitamin C: Antioxidant, collagen production, wound healing, iron absorption.
• Vitamin D: Calcium/phosphate absorption, bone health.
• Vitamin E: Antioxidant, cell protection.
• Vitamin K: Blood clotting, bone health.

1.2.3 Water: Functions

• Body temperature regulation.
• Transportation (solvent and medium).
• Medium for chemical reactions.
• Lubrication and cushioning.
• Waste excretion.
• Digestion and absorption.

2. Role of Cellulose (Dietary Fiber/Roughage)

• Complex carbohydrate in plant cell walls; indigestible by humans.
• Importance:
  • Promotes digestive health (prevents constipation).
  • Aids in waste elimination.
  • May reduce risk of certain diseases.
  • Blood sugar control.
  • Promotes satiety.

3. Balanced Diet

• Meaning: Provides all essential nutrients in right proportions and amounts for growth, maintenance, and optimal health.
• Importance:
  • Optimal growth/development.
  • Maintains good health.
  • Prevents deficiency diseases.
  • Boosts immunity.
  • Provides energy.
  • Manages weight.
  • Reduces risk of chronic diseases.

4. Malnutrition and Deficiency Diseases

• Malnutrition: Deficiencies, excesses, or imbalances in nutrient intake.

4.1 Kwashiorkor

• Causes: Severe protein deficiency.
• Symptoms: Edema (swelling), stunted growth, muscle wasting, skin/hair changes, enlarged liver, apathy.
• Prevention: Adequate protein intake, breastfeeding, diversified diet.

4.2 Marasmus

• Causes: Severe deficiency of all nutrients (carbohydrates, fats, proteins); overall energy and protein deficit.
• Symptoms: Severe wasting ("skin and bones"), stunted growth, drastic weight loss, wrinkled skin, "old man's face," weakness, chronic diarrhea.
• Prevention: Adequate calorie/nutrient intake, food security, early intervention, nutritional support programs.