Flashcards in Lecture 11 Deck (47)
What are the 4 key functions of fat in the body?
- Major energy store and fuel source
- Required for transporting fat soluble vitamins
- Provide essential fatty acids
- Important for insulating and protecting the body
Give examples of two essential fatty acids. What is their function?
Linoleic and alpha-linoleic acid
Important for cell membrane and nervous system
What is the most common type of lipid found in the body and in food?
Where are long-chain fatty acids primarily found?
Meat, fish, vegetable oils
Where are medium and short chain fatty acids found?
What aspect of fatty acids influences the characteristics of foods and the health of the body?
Short or long
Saturated or unsaturated
Location of double bond
What is the state of different fat types at room temperature?
Saturated fats: solid and more resistant to oxidation
Polyunsaturated fats: liquid
Shorter fatty acid chains: softer than long chains
Compare the likelihood of spoilage of monounsaturated and polyunsaturated fat.
Monounsaturated: Slightly less susceptible to spoilage
Polyunsaturated: Spoils most readily
What are the effects of hydrogenation of unsaturated fats?
- Protects against oxidation, therefore prolonging shelf life
- Alters texture
- Acts more like saturated fat
What is the structure of sterols?
Give an example of a well-known sterol
What kind of food are sterols found in?
Both animal and plant foods
In what kind of food is cholesterol found in?
Animal foods only - meat, eggs, fish, poultry, dairy
What can plant sterols interfere with?
Give examples of plant-based sterols
Logicol and Flora Proactiv
What percentage of cholesterol is made in the liver? What is the rest obtained from?
We make about 80% of cholesterol in our liver and 20% is obtained by diet.
What is cholesterol material for?
Bile acids and hormones
What is endogenous and exogenous cholesterol?
Endogenous: made in liver
Exogenous: obtained by diet
What are the roles of sterols?
- Starting material for bile acids, sex hormones, adrenal hormones and vitamin D.
- Structural component of cell membranes.
How much cholesterol does the liver produce a day?
What is a disease associated with cholesterol?
Atherosclerosis is a disease that causes heart attacks. It occurs when cholesterol forms deposits in the artery wall.
How does the mouth contribute to lipid digestion?
In the mouth, salivary glands release lingual lipase. The acid-stable lingual lipase initiates lipid digestion.
How does the stomach contribute to lipid digestion?
Muscle contractions disperse fat into smaller droplets. Fat is exposed to gastric lipase.
What signals the gallbladder to release bile?
What happens to fat in the small intestine?
Emulsified by bile. Prevents them from being attracted to each other.
Emulsified fat is broken down into monoglycerides, glycerol, and fatty acids by pancreatic and intestinal lipase.
Pancreatic cholesterolesterase sterifies some of the esters in cholesterol
Describe the recycling of bile.
In the gallbladder, bile is stored. In the small intestine, bile emulsifies fats. Bile reabsorbed into the blood. In the liver, bile is made from cholesterol. In the colon, bile that has been trapped by soluble fibers is lost in faeces. Don't tend to lose much through this route.
What are the effects of plant sterols on bile recycling?
Plant sterols block the reabsorption of bile into blood from the small intestine, so the liver must manufacture its own cholesterol to make bile. They also increase the loss of bile in faeces.
How do statins affect cholesterol?
They reduce the production of LDL cholesterol by the liver.
What are statins prescribed for?