Dietary Fat, Protein + Carbs Flashcards
Role of fats in the body
Fuel + energy store
Insulation
Protection
Membrane
Structures
Intra/intercellular signalling - phospholipids
Substrate for hormone and prostaglandin synthesis e.g. cholesterol
90% of dietary fats are triaglycerols
What are triaglycerols made up of?
Made up of glycerol + 3 fatty acids
Fatty acids can be saturated, monosaturated or polyunsaturated.
What is the difference?
Saturated = No double bonds
Monounsaturated = 1 double bond
Polyunsaturated = > 1 double bond
What is an essential fatty acid?
2 essential fatty acids, linoleic (omega6) and alpha-linolenic (omega3), cannot be synthesized in the body and must be obtained from food.
Req. for prostaglandins, leukotrienes
Other long fatty acids derived from these EFAs
Cholesterol + role in metabolism
Primary component of cell membranes
Substrate for synthesis of bile acids, steroid hormones + vitamin D Dietary cholestero
little influence on blood cholesterol Increased dietary cholesterol
decreased re-uptake of biliary cholesterol Dietary sources - liver, eggs, shellfish
What are cholesterol + TAGs transported as in the body?
There are different types - VLDL, LDL + HDL.
State where each type transports cholesterol to.
Cholesterol + TAGs transported around the body as lipoproteins (composed of lipid + apoprotein)
VLDL-TAG rich = transports TAG to adipose muscles
LDL = cholesterol rich; Transports cholesterol from liver to cells
HDL = removal of excess cholesterol from peripheral tissues
Raised LDL- cholesterol linked with CVD
HDL-cholesterol inversely related to CVD
A raised LDL-cholesterol is taken up by _______ to form foam cells.
Foam cells accumulate in _____.
They harden which is the process of _____
Macrophages
Blood vessel walls
Atherosclerosis
What type of fats increase/decrease LDL-cholesterol?
Saturated fats increase
MUFA decrease
What does high + low biological value proteins mean?
HBV = all of the essential amino acids in sufficient amounts for protein synthesis (e.g. animal protein - meat)
LBV = lack some essential amino acids (e.g. plant proteins)
Carbohydrate is the main energy source (50% energy)
Where is excess carbohydrate stored?
Stored as Glycogen in the liver + skeletal muscle
Blood glucose levels need to be maintained in tight parameters
Carbohydrates come in 2 forms: Sugars + Polysaccharides (starches)
Name the dietary sources of sugars, starches + non-starch polysaccharide
There are 2 types of NSP. What are they + how does it help the body?
Soluble NSP binds to bile salts. What does this do?
A high fibre diet can have a _____ effect
Sugars are in fruits, vegetables + milk
There is a lot form added sources
Starches are in bread, potatoes, rice, pasta, cereals etc
NSP are in fruits, veg, wholegrains, oats. nuts + brown rice
There is insoluble + soluble NSP
Insoluble NSP (e.g. wholegrains + nuts) it adds bulk to stools, sofetning it + helps to pass more quickly through GIT - reducing transit time through GIT.
Soluble NSP delays gastric emptying - making you fell fuller for longer. It blunts postprandial blood glucose response ny slowing digestion
It binds to bile salts, decreasing cholesterol uptake
High fibre diet can have hypocholesterolaemic effect.
NSP act as a substrate for bacterial fermentation in the colon.
What does bacteria produce when NSP binds to bacteria?
Produce SCFA which is absorbed by colonic mucosa
Produces butyric acid; important fuel for mucosal cells of the colon
Faecal bulk
A diet high in fibre reduces the risk of _____
Colorectal cancer
What is glycaemic index?
What is the difference between a high + low GI?
Glycaemic index relates the conc of glucose in the plasma after food consumption
Low GI = broken down + absorbed slowly
High GI = broken down + absorbed quickly
