Carbohydrates And Sugars Flashcards
(40 cards)
What are the functions of carbohydrates
- energy, physical and mental
- stimulate insulin production and satiety
- promote digestive health
How much energy does 1g carb contain
4kal
How does carbohydrates effect insulin
Absorbed
Blood sugar rises
Insulin released
Insulin allows muscle, liver and fat cells to absorb carbohydrates for energy
What is the chemical composition of carbohydrate
Carbon, hydrogen, oxygen
1:2:1
What are the two types of carbohydrates
Simple
- monosaccharides
-disaccharide
Complex
- polysaccharide
What are the three types of monosaccharides
Glucose
Fructose
Galactose
What are the three types of disaccharides
Maltose
Sucrose
Galactose
What are the two types of polysaccharides
Starches
Fibres
Explain monosaccharides
Glucose = main = sweets, honey, sugar, fruit and juice
Fructose = transported to liver and metabolised = honey, fruit, veg
Galactose = milk sugar
Explain disaccharide
Maltose
- 2x glucose
- plants and cereal grains, certain veg
Sucrose
- glucose + fructose
- refined table sugar, honey, maple syrup
Lactose
- glucose + galactose
- milk and products
Explain polysaccharides
Main types in diet are long chains of glucose
Also long chains of indigestible e.g cellulose and gums
Starches
- potatoes, bread ect
Fibres
- whole grains, beans, nuts
What parts of the body are involved in carbohydrate digestion
Mouth
Small intestines
Small intestine brush border
Liver
Large intestine
Explain carbohydrate digestion in the mouth
Mechanical digestion
Enzymatic digestion
- break down larger carbon such as starch
Salivary amylase
- break into shorter polysaccharides and maltose
- large molecules can’t be absorbed directly so need this breakdown
- smaller ones don’t go through this
Explain enzymatic digestion in the small intestine
Uses pancreatic amylase, secreted by pancreas
- into shorter polysaccharides and maltose
Explain digestion of carbohydrates in small intestinal brush border
Disaccaridases
Break di into mono
Mono the absorbed into the bloodstream for transport into the liver
Explain monosaccharide metabolism in the liver
Glycogenesis
- stored as liver glycogen
- stored as muscle glycogen
Blood glucose regulation
- glucose enters the bloodstream to maintain blood glucose levels
Energy production
- seed in glycolysis to produce ATP
Conversion into fat
- lipogenesis
- stored in body as fat cells o
Explain the role of the large intestine in carbohydrate metabolism
Gut micro biota, colonic bacteria = fermentation of dietary fibre to feed gut microbes
Fermentation releases energy
Short chain fatty acids released during fermentation, support gut health and other bodily functions
Gas production is a natural biproduct of fermentation
What is the role of dietary fibre
- reduce constipation
- reduce cv disease and cancer
- reduce type 2 diabetes and obesity
- increase gut health
- increase mental health
What is lactose intolerance
In normal people, lactose is digested at intestinal brush border inti glucose and galactose via lactase
Intolerance = body dosent produce enough lactase to break down lactose, meaning it passes into large intestine
= gastrointestinal symptoms
What does eat lancet say about carbohydrates
Minimise added sugar
Explain current intakes vs planetary health
No groups meet recommended targets, especially of whole grains + nuts
What are the environmental effect of carbohydrates
Sustainable
What is glycemic index
Rank based on speed of digestion/ how quickly raised blood sugar
Used to just look at fibre content
Methods are reductionist and simplistic, ignore complexity of carbohydrates quality
Explain the holistic model of carbohydrate quality
Combines traditional indices e.g protein quality and environmental stability, degree of processing
Method still needs more work
