Lecture Notes: Macronutrients

Introduction

• Presenter: Cathy from Level Up RN
• Topics Covered: Carbohydrates, lipids, and proteins
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Carbohydrates

• Primary Source of Energy
  • Controls blood glucose and insulin metabolism
  • Found in vegetables, fruits, dairy products, whole grains
• Types of Carbohydrates
  • Simple Carbohydrates
    • Easy to digest, provide quick energy
    • Quickly increase blood glucose levels
    • Examples: fruit juice, honey, candy
  • Complex Carbohydrates
    • Provide more fiber, take longer to digest
    • Slowly increase blood glucose levels
    • Examples: apples, brown rice, lentils
• Glycogen
  • Stored carbohydrate energy in liver and muscles
  • Broken down during glucogenolysis when body needs glucose

Importance of Fiber

• Health Benefits
  • Increases healthy bacterial growth in colon
  • Softens and bulks stool
  • Stabilizes blood glucose levels
  • Reduces risk of diverticulitis, hemorrhoids, colorectal cancer, coronary artery disease
• Recommended Intake
  • 38 grams/day for men, 25 grams/day for women

Lipids

• Main Source of Stored Energy
  • Provide cell structure and function
  • Important for temperature regulation and organ protection
• Types of Fats
  • Saturated Fats
    • Found in animal products (meat, dairy)
    • Increase LDL levels, risk of heart disease
  • Trans Fats
    • Found in processed foods (partially hydrogenated oils)
    • Increase LDL, decrease HDL levels
  • Unsaturated Fats
    • Heart-healthy, found in avocados, nuts, seeds, olive oil
    • Recommended over saturated and trans fats

Cholesterol

• Role in the Body
  • Component of cell membranes, needed for vitamin D and hormone synthesis, digestion
• Types:
  • LDL (Low-Density Lipoprotein): Bad cholesterol
  • HDL (High-Density Lipoprotein): Good cholesterol
• Intake Recommendations
  • Below 300 mg/day (200 mg/day for high-risk individuals)

Proteins

• Functions
  • Tissue building and repair, immune system function, energy
• Food Sources
  • Seafood, meat, poultry, eggs, soy, nuts, seeds, dairy
• Amino Acids
  • 9 essential amino acids (must be obtained from diet)
  • 11 non-essential amino acids (produced by the body)
• Types of Proteins
  • Complete Proteins
    • Contain all 9 essential amino acids (e.g., animal sources, soy)
  • Incomplete Proteins
    • Lack one or more essential amino acids
    • Complementary proteins can be combined to provide all essential amino acids (e.g., rice and beans)

Protein Metabolism

• Anabolism
  • Assembly of amino acids into proteins
• Catabolism
  • Breakdown of proteins for energy
• Nitrogen Balance
  • Balance between anabolism and catabolism
  • Positive Nitrogen Balance: Protein synthesis exceeds breakdown (e.g., growth spurts, pregnancy)
  • Negative Nitrogen Balance: Protein breakdown exceeds synthesis (e.g., starvation, severe injury)

Conclusion

• Quiz Questions
  1. Stored carbohydrate energy in liver and muscles: Glycogen
  2. Main source of stored energy in the body: Lipids
  3. Breakdown of protein for energy: Catabolism
• Recommendation: Revisit the material and use repetition for effective learning.

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