Ch+4+-+Carbohydrates+and+Diabetes

CARBOHYDRATES

Learning Objectives

  • Understand the classification of carbohydrates
  • Understand carbohydrate digestion and absorption
  • Discuss diabetes: types, risk factors, long-term consequences, and treatment
  • Understand the function of carbohydrates and their relation to health issues

WHAT ARE CARBOHYDRATES?

  • Organic compounds consisting of three elements:
    • Carbon (C)
    • Hydrogen (H)
    • Oxygen (O)
  • Two Main Classes:
    • SIMPLE Carbohydrates: These are sugars.
    • COMPLEX Carbohydrates: These include starches and fibers.

Classification of Carbohydrates

  • Simple Carbohydrates
    • Monosaccharides:
    • Glucose
    • Fructose
    • Galactose
    • Disaccharides:
    • Maltose (glucose + glucose)
    • Sucrose (glucose + fructose)
    • Lactose (glucose + galactose)
    • Polysaccharides (Complex Carbohydrates):
    • Glycogen
    • Starches (Amylose and Amylopectin)
    • Fibers (Soluble and Insoluble)
    • Note: Glycogen is a polysaccharide but not a common dietary source of carbohydrates.

Simple Carbohydrates (Sugars)

Monosaccharides

  1. GLUCOSE
    • Known as blood sugar; it is an essential energy source.
    • One of the two sugars found in every disaccharide.
  2. GALACTOSE
    • Found only in a few foods, notably milk as lactose which is bound to glucose.
  3. FRUCTOSE
    • Naturally occurs in fruits and honey; is the sweetest of the sugars.

Disaccharides

  • Sucrose (Table sugar, glucose + fructose)
  • Lactose (Milk sugar, glucose + galactose)
  • Maltose (Produced during starch digestion, glucose + glucose)

Examples of Lactose Content in Foods

  • Whole-wheat bread, 1 slice: 0.5 g
  • Dinner roll, 1: 0.5 g
  • Cheese (Cheddar or American), 1 oz: 0.5 g
  • Milk, 1 c: 12.0 g
  • Yogurt (low-fat), 1 c: 15.0 g
  • Note: Yogurt may have an increased lactose content due to enrichment with nonfat milk solids.

Chemical Reactions Involving Carbohydrates

Condensation Reaction

  • Two molecules combine to form one larger product, releasing water.
  • Example:
    • Glucose + Fructose → Sucrose + H₂O
    • Water is released during the formation of the disaccharide.

Hydro