Nutrition Lecture Notes

Key Concept: Carbohydrates

• Carbohydrates include sugars and molecules that breakdown into sugars.
• Two types of carbohydrates:
  • Simple carbohydrates: Monosaccharides (e.g., glucose, fructose, galactose).
  • Complex carbohydrates: Include disaccharides (e.g., lactose, maltose, sucrose) and polysaccharides.

Structure of Carbohydrates

• Simple sugars: Single sugar molecules.
• Disaccharides: Two sugar molecules linked.
• Complex carbohydrates:
  • Oligosaccharides: 3-10 linked sugars.
  • Polysaccharides: More than 10 linked sugars.

Digestion of Carbohydrates

• During digestion, complex carbohydrates are broken into monosaccharides for energy.
• Blood sugar levels rise when carbohydrate-rich foods are consumed, but the effect varies.

Types of Carbohydrates in Foods

• Starch vs. Fiber:
  • Both are polysaccharides from plants, but differ in their linkage.
  • Starches: Easily digested due to alpha linkages (e.g., crackers, white bread).
  • Fiber: Indigestible beta bonds, resulting in slower glucose release.
  • Resistant Starch: Starch that cannot be cleaved due to fiber trapping.

Glycemic Index

• Measure of how much a food raises blood sugar levels.
• High glycemic index: Foods like soda and white bread.
• Low glycemic index: Foods like vegetables, fruits, whole grains, and proteins (eggs, cheese, meats).

Insulin and Blood Sugar Management

• Insulin: Hormone from the pancreas, essential for transferring sugar from blood to tissues.
• Insulin sensitivity: How effectively insulin lowers blood sugar.
• Insulin resistance: Reduced sensitivity to insulin, leading to higher blood sugar and insulin levels.

Metabolic Syndrome

• Chronic high carbohydrate intake can lead to insulin resistance.
• Metabolic syndrome: Includes high blood sugar, increased waist circumference, high blood pressure.
• Increased risk of cardiovascular disease and type II diabetes.
• Prevalence: 32% of the U.S. population.

Dietary Considerations

• Sugar is sugar, regardless of whether food tastes sweet or not.
• Excessive carbohydrate intake can be problematic.
• Consider limiting high-carbohydrate foods.