Stages of Digestion to Know for Intro to Nutrition

Understanding the stages of digestion is key to grasping how our bodies process food. From ingestion to elimination, each step plays a vital role in breaking down nutrients and ensuring our bodies get what they need to function well.

1. Ingestion

   • The process of taking food and liquids into the mouth.
   • Involves the use of teeth and saliva to prepare food for digestion.
   • Begins the digestive process by breaking down food into smaller pieces.

2. Mechanical Digestion

   • Involves the physical breakdown of food into smaller particles.
   • Occurs primarily in the mouth (chewing) and stomach (churning).
   • Increases the surface area of food, making it easier for enzymes to act during chemical digestion.

3. Chemical Digestion

   • The process of breaking down food into simpler molecules through enzymatic action.
   • Begins in the mouth with saliva and continues in the stomach and small intestine.
   • Essential for converting macronutrients (carbohydrates, proteins, fats) into absorbable units (sugars, amino acids, fatty acids).

4. Absorption

   • The process by which nutrients from digested food are taken up into the bloodstream.
   • Primarily occurs in the small intestine, where villi and microvilli increase surface area for absorption.
   • Critical for delivering essential nutrients to cells and tissues throughout the body.

5. Elimination

   • The final stage of digestion, involving the removal of indigestible substances from the body.
   • Occurs through the large intestine, where water is reabsorbed and waste is formed into feces.
   • Important for maintaining digestive health and preventing the buildup of toxins in the body.