Lecture 6 - Carbs Flashcards
What are the different classifications for carbs?
- monosaccharides
- disaccharides
- polysaccharides
Starch and non starch
-dietary fibers
soluble and non soluble
Intrinsic vs extrinsic sugars
depends where you find them and if they are attached to something then it is intrinsic. For instance, sugars that are contained within plant cell walls. Extrinsic are in a free solution and provide substrate for oral bacteria. lead to formation of dental plaque and caries. Easy to consume and so easy to get obese. Omly exception is lactose.
What is an oligo saccharide?
Contains 3-9 monosaccharide units wheras poly has more than 10.
What are sugar alcohols?
They are formed by the reduction of the aldehyde group of a monosaccharide to a hydroxyl (-OH) group.
Where are sugar alcohols absorbed?
They are absorbed in the GIT and metabolised slowly.
glycemic index of sugar alcohols in comparison to other CHOs?
They have a lower glycemic index than other CHO. They have a minor effect on the concentration of glucose in blood and so it widely used in foods suitable for those who have diabetes.
Energy yield of sugar alcohol in comparison to glucose?
approximately half of glucose. Not exactly suitable in weight reducing diets.
What is xylitol?
It is a sugar alcohol that is formed by the reduction of the 5C sugar xylose (an isomer of ribose). It is tooth friendly as it has anti cariogenic actions.
What is the glycemic index?
It is a means of comparing quantitatively the blood glucose responses from ingestion of equivalent amount of digestable CHO from different foods.
The effect of 50g CHO in a particular food on blood glucose levels compared to 50g of glucose.
If CHO has a high glycemic index then?
greater insulin secretion after the meal
What is the glycemic load?
The index times the amount of CHO in a standard serving size of that food. Index of glycemic response.
What is glycemic response?
The rate, magnitude and duration of the rise in blood glucose that occurs after food is consumed.
How are fibers broken down?
They can not be digested by the human body but they can be fermented to some extent by intestinal bacteria. The products produced can be absorbed and metabolised as metabolic fuel. There are beneficial health effects.
What is dietary fiber?
Mixture of indigestible CGO and lignin that is found intact in plants.
What is functional fiber?
Isolated indigestable CHO that has been shown to have beneficial effects on humans.
