Fibre

• • Long complex chains tightly bound tgt by glycosidic bonds = Plant cell wall
  • Diff. for the body to break down
  • not digested & absorbed in the small intestine --> Moves to colon --> Digested by resident bacteria (NOT all)
• Soluble: Rapidly fermentable fibre (e.g. Beans, Oat bran, Avocado, Berries); Broken down by bacteria in the upper part of the large intestine
• Insoluble: Poorly fermentable fibre (e.g. Whole grains, Legumes, Wheat germ, Beans, Flaxseed, Leafy vegetables, Nuts)
• Old beliefs:

  • Just an inert component of food
  • Facilitate waste removal in the gut
• European Food Safety Authority suggests can improve weight maintenance:

  • Foods that contain fibre = Fibrous in nature
  • Mastication (Chewing) require time and effort
  • Prolonged exposure to food in the mouth allows time for the activation of signaling mechanisms that mediate satiety
  • Satiety: also driven by gastric distention + delayed gastric emptying (b/c fibre absorbs water --> increase volume & viscosity)
• Reach the colon --> Fermented by commensal bacteria (e.g. Bifidobacteria & Lactobacil)

  • Production of gases & short chain fatty acids = energy source for colonic epithelial cells
  • Influence hepatic insulin sensitivity
  • Anti-inflammatory properties (Prevent certain cancers esp. colorectal cancer)
• • Associated w/ delayed absorption of glucose --> Keep blood glucose levels stable
  • Reduce risk of heart disease, type 2 diabetes, hypertension, high cholesterol
• Men & Women: 25 – 30 g daily
• Harm of eating processed carbohydrate

  • Modern Western Diets: High in processed carbohydrate + saturated fats - Processed = Refined
  • Leading to loss of fibre, vitamins, minerals
  • Often w/ added sugars, artificial sweeteners, fats (Improve taste & texture; Increase shelf life)
  • Examples: Pasta (white pasta), White rice, Cakes, Cookies, Muffins, Most baked desserts
• Processed Carbohydrate

  Characteristics:

  • High in calorie but X nutritional value = Empty calories
  • Low in fibre
  • Extremely palatable
  • Digested quickly --> High GI, Overeating