Carbs & Fibre Flashcards
What are carbohydrates (CHO)?
Key energy source; organic compounds composed of carbon, oxygen, and hydrogen.
What is the energy value of carbohydrates?
1g CHO = 17 kJ of energy.
What are monosaccharides?
Directly absorbed carbohydrates (e.g., glucose, fructose).
What are types of Carbohydrates?
Monosaccharides, Disaccharides, Polysaccharides, Oligosaccharides
What are disaccharides?
Carbohydrates broken down by enzymes (e.g., maltase, sucrase).
What are oligosaccharides?
Fiber-like carbohydrates; fermented by gut bacteria; may have immunomodulatory effects.
What are polysaccharides?
Include starch and dietary fiber (e.g., amylose – slow digestion; amylopectin – fast digestion).
How does starch digestion begin?
Begins in the mouth with salivary α-amylase.
What happens to glycogen?
Stored form of CHO, broken down by glucagon for energy.
What happens to disaccharides during digestion?
Hydrolysed into monosaccharides in enterocytes.
What happens to monosaccharides after digestion?
Travel to the liver via the hepatic portal vein.
What happens to fructose and galactose in the liver?
Converted to glucose.
What is the primary role of carbohydrates?
Provide fuel for cell metabolism and energy production.
What are the structural roles of carbohydrates?
Combine with proteins/lipids to form glycoproteins and glycolipids.
How do carbohydrates support gut microbiota?
Complex CHOs ferment to produce short-chain fatty acids.
How do some oligosaccharides support the immune system?
They modulate the immune system (e.g., in breast milk).
What metabolic processes do carbohydrates regulate?
Involved in blood glucose, insulin, triglycerides, and cholesterol metabolism.
What are dietary sources of carbohydrates?
Grains, legumes, fruits and root vegetables, dairy, processed foods.
What role does dietary fibre play in health?
Dietary fibre plays a critical role in cholesterol management, gut health, and regularity.
What is the benefit of resistant starch?
Resistant starch supports the microbiome and produces beneficial compounds in the colon.
What is dietary fibre?
The indigestible portion of plant foods, also known as non-starch polysaccharides (e.g., cellulose).
How is dietary fibre fermented?
Fermented by gut bacteria in the large intestine to produce short-chain fatty acids and certain vitamins.
What is soluble fibre?
Fibre that dissolves in water, forming a gel and is easily fermented in the colon, producing short-chain fatty acids.
What are the health benefits of soluble fibre?
Lowers blood cholesterol by binding bile and supports colon health.
What is insoluble fibre?
Fibre that adds bulk and speeds up stool passage in the colon, supporting digestive regularity.
What is resistant starch?
A type of starch that resists digestion and is fermented in the colon.
What are the types of resistant starch?
- Physically Inaccessible/Indigestible Starch: Found in whole/partially milled grains and legumes.
- Enzymatically Resistant Starch: Found in raw potato and green banana (high amylose starch).
- Retrograded Starch: Found in cooked and cooled starches like rice or potatoes.
What is a key property of resistant starch?
Higher amylose content (straight-chain starch molecules) increases resistance to digestion.
What are the health benefits of resistant starch?
Promotes gut health and supports microbiome diversity, contributes to the production of short-chain fatty acids.
How are carbohydrates stored in the body?
Stored as glycogen.
What is the total energy intake for Carbohydrates?
45-65% (Includes fibre)
What is the RDI for Fibre?
Female: 25 g/day
Male: 30 g/day
