Macronutrients and Micronutrients Overview

Macronutrients

• Carbohydrates

  • Primary energy source.
  • Types: Simple (sugars) and complex (starches, fibers).
  • Recommended intake: 45-65% of total daily calories.

• Proteins

  • Essential for growth, repair, and maintenance of body tissues.
  • Composed of amino acids (20 total, 9 essential).
  • Recommended intake: 10-35% of total daily calories.

• Fats

  • Important for energy storage, hormone production, and cell function.
  • Types: Saturated, unsaturated (monounsaturated, polyunsaturated), and trans fats.
  • Recommended intake: 20-35% of total daily calories.

Micronutrients

• Vitamins

  • Organic compounds required in small amounts.
  • Types:
    • Fat-soluble (A, D, E, K)
    • Water-soluble (B-vitamins, C)

• Minerals

  • Inorganic elements important for various bodily functions.
  • Major minerals (e.g., calcium, potassium, magnesium) and trace minerals (e.g., iron, zinc).

• Functionality

  • Support immune function, energy production, bone health, and more.
  • Deficiencies can lead to health issues.

Digestion Process

1. Ingestion

   • Entry of food into the digestive system through the mouth.

2. Mechanical Digestion

   • Physical breakdown of food (chewing, churning).
   • Increases surface area for enzymes.

3. Chemical Digestion

   • Enzymatic breakdown of food into absorbable units.
   • Begins in the mouth and continues in the stomach and small intestine.

4. Absorption

   • Nutrients are absorbed mainly in the small intestine.
   • Transported into the bloodstream or lymphatic system.

5. Elimination

   • Removal of indigestible substances and waste products.

Organs Involved in Digestion

• Mouth

  • Mechanical and chemical breakdown; saliva contains enzymes.

• Esophagus

  • Transports food to the stomach via peristalsis.

• Stomach

  • Secretes acid and enzymes; further digests food into chyme.

• Small Intestine

  • Main site for nutrient absorption (duodenum, jejunum, ileum).

• Large Intestine

  • Absorbs water and electrolytes; compacts waste into feces.

• Liver

  • Produces bile for fat emulsification; processes nutrients.

• Pancreas

  • Produces digestive enzymes and bicarbonate to neutralize stomach acid.

• Gallbladder

  • Stores and releases bile into the small intestine.

Digestive Enzymes

• Salivary Amylase

  • Breaks down carbohydrates in the mouth.

• Pepsin

  • Breaks down proteins in the stomach.

• Pancreatic Enzymes

  • Include amylase (carbohydrates), lipase (fats), proteases (proteins).

• Brush Border Enzymes

  • Located in the small intestine, further digest carbohydrates and peptides.

• Function

  • Enzymes are specific to substrates and essential for efficient digestion and nutrient absorption.

Macronutrients

• Carbohydrates: Serve as the primary energy source for the body.

  • Types:
    • Simple carbohydrates: sugars.
    • Complex carbohydrates: starches and fibers.
  • Recommended intake: 45-65% of total daily calories.

• Proteins: Critical for growth, tissue repair, and maintenance.

  • Composed of 20 amino acids, of which 9 are essential.
  • Recommended intake: 10-35% of total daily calories.

• Fats: Vital for energy storage, hormone synthesis, and cellular functions.

  • Types:
    • Saturated fats.
    • Unsaturated fats (monounsaturated and polyunsaturated).
    • Trans fats.
  • Recommended intake: 20-35% of total daily calories.

Micronutrients

• Vitamins: Organic compounds needed in small quantities for various bodily functions.

  • Types:
    • Fat-soluble: Vitamins A, D, E, K.
    • Water-soluble: B vitamins and vitamin C.

• Minerals: Inorganic elements essential for multiple physiological processes.

  • Includes major minerals (e.g., calcium, potassium, magnesium) and trace minerals (e.g., iron, zinc).
  • Functions: Support immune health, energy production, bone integrity, among others.
  • Deficiencies can result in significant health problems.

Digestion Process

• Ingestion: The initial stage where food enters the digestive system through the mouth.
• Mechanical Digestion: Involves physical breakdown of food through actions like chewing and churning, enhancing enzyme effectiveness.
• Chemical Digestion: Involves enzymatic processes that reduce food to absorbable units, starting in the mouth and continuing in the stomach and small intestine.
• Absorption: Primarily occurs in the small intestine where nutrients enter the bloodstream or lymphatic system.
• Elimination: The process of expelling indigestible substances and waste from the body.

Organs Involved in Digestion

• Mouth: Initiates mechanical and chemical digestion with salivary enzymes.
• Esophagus: Transports food to the stomach using peristalsis.
• Stomach: Produces acids and enzymes, converting food into a semi-liquid form known as chyme.
• Small Intestine: The primary site for nutrient absorption, divided into duodenum, jejunum, and ileum.
• Large Intestine: Absorbs water and electrolytes; compacts remaining waste into feces.
• Liver: Synthesizes bile for fat processing and nutrient metabolism.
• Pancreas: Secretes digestive enzymes and bicarbonate to neutralize stomach acid.
• Gallbladder: Stores and releases bile into the small intestine.

Digestive Enzymes

• Salivary Amylase: Initiates carbohydrate digestion in the mouth.
• Pepsin: Breaks down proteins in the stomach.
• Pancreatic Enzymes: Includes multiple enzymes:
  • Amylase: Targets carbohydrates.
  • Lipase: Breaks down fats.
  • Proteases: Digests proteins.
• Brush Border Enzymes: Located in the small intestine, these enzymes further digest carbohydrates and peptides.
• Functionality: Digestive enzymes are substrate-specific and crucial for efficient digestion and nutrient absorption.

Test your knowledge on macronutrients like carbohydrates, proteins, and fats, along with essential micronutrients such as vitamins and minerals. Understand their roles, types, and recommended intake for a balanced diet. Ideal for those studying nutrition or health science.