Which fatty acids are considered essential?
Linoleic, linolenic, and arachidonic acids.
p.10
Essential Fatty Acids
What is the role of linolenic acid in the body?
Necessary for the synthesis of prostaglandin E3 series and other omega-3 fatty acids.
p.10
Essential Fatty Acids
What are essential fatty acids?
Fatty acids that must be obtained from the diet.
How is cholesterol absorbed in the body?
Cholesterol is incompletely absorbed.
p.8
Classification of Dietary Lipids
What defines polyunsaturated fats?
They have 2 or more double bonds.
p.20
Lipid Digestion Process
What is the role of colipase in the activity of pancreatic lipase?
Colipase binds lipase to mixed micelles and prevents inhibition of lipase by bile salts.
How are short and medium chain fatty acids (≤ 10C) absorbed?
Without the aid of bile salts.
p.26
Triacylglycerol Synthesis
What pathway synthesizes the remainder of triacylglycerol?
The phosphatidic acid pathway.
p.14
Classification of Dietary Lipids
What is significant about the side chains of phytosterols?
They are attached to carbon 17.
p.7
Classification of Dietary Lipids
What is a characteristic of monounsaturated fats?
They have one double bond.
p.22
Role of Fats in Nutrition
What are bile salts derived from?
Cholesterol in the liver.
p.12
Essential Fatty Acids
What are the symptoms of linolenic (ω-3) deficiency?
Impaired visual acuity, delayed cognitive development, cardiovascular effects.
p.25
Triacylglycerol synthesis
What is the primary pathway for triacylglycerol (TAG) synthesis?
The monoacylglycerol pathway.
p.21
Lipid Digestion Process
What is the function of pancreatic esterase?
It hydrolyzes triglycerides (TAG) to glycerol and free fatty acids (FFA).
p.3
Sources of Dietary Fats
How does the fat content in poultry compare to that in other meats?
Poultry is intermediate in fat content.
p.29
Disorders of Lipid Digestion and Absorption
What is steatorrhea?
Presence of excess fat in the stool.
p.28
Disorders of Lipid Digestion and Absorption
What is abetalipoproteinemia?
A condition that can result in fat malabsorption and steatorrhea.
p.25
Sources of Dietary Fats
How are long-chain fatty acids (>12 C) processed in the body?
They bind to fatty acid-binding proteins (FAB) and are transported to the endoplasmic reticulum (ER).
p.4
Sources of Dietary Fats
What is the state of most plant oils at room temperature?
Liquid, with the exception of coconut oil.
Which vitamins are fat-soluble and absorbed in lipid micelles?
Vitamins A, D, E, K and cholesterol.
p.5
Classification of Dietary Lipids
What are sterols?
A class of dietary lipids.
What happens to cholesterol after it is absorbed?
It is dissolved in micelles and re-esterified inside the cells.
p.19
Lipid Digestion Process
Where is lingual lipase produced?
Cells at the back of the tongue.
p.3
Sources of Dietary Fats
What type of fatty acids does butter contain in small amounts?
Very little polyunsaturated fatty acids but a fair amount of short-chain fatty acids.
p.30
Pharmaceutical Interventions for Fat Malabsorption
How do the fatty-acyls in Olestra behave?
They are resistant to the action of lipases.
p.31
Lipid Digestion Process
What role do bile salts play in fat digestion?
They help in emulsification and form micelles.
p.16
Disorders of Lipid Digestion and Absorption
What causes can decrease absorption of lipids?
Conditions such as pancreatic insufficiency, bile salt deficiency, and intestinal disorders can decrease lipid absorption.
p.13
Role of Fats in Nutrition
What role does cholesterol play in cell membranes?
It organizes cell membranes and controls their permeability.
p.10
Essential Fatty Acids
What is linoleic acid and where is it found?
An ω6 fatty acid found in safflower oil, sunflower oil, and corn oil.
p.10
Essential Fatty Acids
What is the role of linoleic acid in the body?
Necessary for the synthesis of prostaglandins E1 and E2 series.
p.9
Disorders of Lipid Digestion and Absorption
What is the effect of trans fatty acids on LDL and HDL cholesterol levels?
They raise LDL and reduce HDL.
p.9
Disorders of Lipid Digestion and Absorption
What health risks are associated with trans fatty acids?
They may be carcinogenic and are implicated in neurodegenerative diseases.
p.29
Disorders of Lipid Digestion and Absorption
What can cause steatorrhea?
Any process that interrupts lipid digestion and/or absorption.
p.29
Disorders of Lipid Digestion and Absorption
What can lead to insufficient bile?
Biliary obstruction or severe liver disease.
p.28
Disorders of Lipid Digestion and Absorption
What is a mucosal disease that can lead to steatorrhea?
Conditions like villous atrophy or lymphangiectasia.
p.30
Pharmaceutical Interventions for Fat Malabsorption
What is a potential downside of using Olestra?
It may reduce absorption of fat-soluble vitamins.
p.31
Role of Fats in Nutrition
What is the energy value of fats?
Fats have high energy value.
Where does absorption of lipids take place?
In the jejunum by simple diffusion.
p.14
Essential Fatty Acids
Which phytosterol is of current interest for its hypocholesterolemic properties?
Stigmasterol from soybean oil.
p.13
Role of Fats in Nutrition
What are the precursors that cholesterol helps produce?
Bile acids and steroid hormones.
p.5
Classification of Dietary Lipids
What are triglycerides composed of?
Glycerol and 3 fatty acids.
p.17
Lipid Digestion Process
What must happen to hydrophobic molecules before they can be absorbed?
They must be hydrolyzed and emulsified into very small droplets (micelles).
p.10
Essential Fatty Acids
What is linolenic acid and where is it found?
An ω3 fatty acid found in linseed oil, canola oil, soybean, and fatty marine fish.
p.4
Sources of Dietary Fats
How do phytosterols affect cholesterol absorption?
They interfere with the absorption of cholesterol.
What are the omega-3 fatty acids mentioned?
Linolenic acid (18:3), eicosapentaenoic acid (20:5), and docosahexaenoic acid (22:6).
p.2
Role of Fats in Nutrition
What metabolic process do fats serve as precursors for?
Prostaglandin metabolism.
p.28
Disorders of Lipid Digestion and Absorption
What can interfere with the delivery of bile salts into the duodenum?
Conditions that affect bile salt delivery can decrease lipid absorption.
p.29
Disorders of Lipid Digestion and Absorption
What occurs when digestion proceeds but absorption is compromised?
Lack of bile salts affects absorption.
p.1
Dietary Fat Intake Variations
What may have contributed to the decrease in dietary fat intake in the US?
An increase in total caloric intake.
p.31
Lipid Digestion Process
Which enzymes act in the stomach during fat digestion?
Gastric lipase and lingual lipase.
p.18
Lipid Digestion Process
What enzymes are involved in lipid digestion in the small intestine?
Pancreatic enzymes and bile salts.
p.17
Sources of Dietary Fats
What are the components that make up the remaining less than 10% of dietary lipids?
Phospholipids, cholesterol and cholesteryl esters, free fatty acids.
p.11
Essential Fatty Acids
Why is ω-6 EFA deficiency rare in this country?
Because vegetable oils and their derivatives are ingested in large quantities.
p.21
Lipid Digestion Process
What is the role of cholesterol esterase?
It hydrolyzes cholesterol esters to free fatty acids (FFA) and cholesterol.
p.5
Classification of Dietary Lipids
What is the role of phospholipids in dietary lipids?
They are one of the main classes of dietary lipids.
p.22
Lipid Digestion Process
What are mixed micelles composed of?
Bile salts, cholesterol, phospholipid (PC), and digestive products.
p.9
Sources of Dietary Fats
Where are trans fatty acids commonly found?
In commercially fried foods, baked goods, margarines, and vegetable shortening.
p.19
Lipid Digestion Process
Where does gastric lipase act during digestion?
At the surface of lipid droplets.
What types of fatty acids are virtually all absorbed?
Free fatty acids (FFA) and monoacylglycerols (MAG).
p.30
Pharmaceutical Interventions for Fat Malabsorption
What digestive issue may Olestra cause?
It may cause steatorrhea.
p.31
Sources of Dietary Fats
What are the two main sources of dietary fats?
Animal sources and plant sources.
p.31
Chylomicron Formation
What is TAG resynthesized with in intestinal cells?
Cholesterol ester and phospholipid.
p.16
Disorders of Lipid Digestion and Absorption
What happens if lipids are not absorbed?
Malabsorption can lead to deficiencies in essential fatty acids and fat-soluble vitamins, resulting in various health issues.
p.21
Lipid Digestion Process
What does Phospholipase A2 do?
Removes fatty acid from the sn2 position of phospholipids.
p.8
Sources of Dietary Fats
Which oils are sources of polyunsaturated fats?
Safflower oil, soybean oil, corn oil.
How are most lipids absorbed in the body?
By simple diffusion across the membrane in the form of micelles.
p.20
Lipid Digestion Process
How is procolipase converted to colipase?
Procolipase is converted to colipase by trypsin.
p.20
Lipid Digestion Process
What specific ester links does pancreatic lipase act on?
Pancreatic lipase is specific for the primary ester links 1 and 3.
p.28
Disorders of Lipid Digestion and Absorption
What happens to stool if lipids are not absorbed properly?
It will contain high amounts of fat.
p.28
Disorders of Lipid Digestion and Absorption
What is one cause of decreased lipid absorption related to pancreatic function?
Pancreatic exocrine deficiency.
p.29
Disorders of Lipid Digestion and Absorption
What can cause insufficient pancreatic enzymes?
Conditions like cystic fibrosis or pancreatitis.
p.31
Classification of Dietary Lipids
How are dietary lipids classified?
Into TAG, phospholipids, and sterols.
p.12
Essential Fatty Acids
What are the symptoms of linoleic (ω-6) deficiency?
Dermatitis, impaired growth, impaired fertility.
p.6
Classification of Dietary Lipids
What is the melting point of saturated fats?
They have a high melting point.
p.11
Essential Fatty Acids
What is the optimal percentage of calories from ω-6 EFA for health?
12%-14% of calories (40% of dietary fat).
p.5
Classification of Dietary Lipids
What are the three main classifications of dietary lipids?
Triglycerides, phospholipids, and sterols.
p.22
Lipid Digestion Process
What is the role of bile salts in digestion?
They permit emulsification of lipid digestion products into micelles.
p.9
Role of Fats in Nutrition
What benefits do trans fatty acids provide in food products?
They improve stability and shelf life.
p.2
Role of Fats in Nutrition
What structural role do fats play in the body?
They are necessary components of cell membranes.
p.3
Sources of Dietary Fats
What does butter primarily consist of?
Milk fat, moisture, and a little protein.
p.19
Lipid Digestion Process
What are the products of TAG hydrolysis by lipases?
1 free fatty acid (FFA) and 1,2-diacylglycerol.
p.31
Essential Fatty Acids
What types of fatty acids exist?
Saturated, monounsaturated, polyunsaturated, and trans fats.
p.6
Sources of Dietary Fats
In which foods are saturated fats largely found?
Meat, poultry, dairy foods, palm and coconut oils.
How is cholesterol absorbed in the body?
Dissolved in lipid micelles.
p.27
Lipid Digestion Process
What are the lipids reassembled into in the intestinal epithelial cells?
TAG, PL, and cholesterol esters.
p.2
Role of Fats in Nutrition
What is one of the satiety values of dietary fats?
They contribute to the feeling of fullness.
How are sterols transported out of the intestinal cells?
They are pumped out by ABC transporters.
p.30
Pharmaceutical Interventions for Fat Malabsorption
What are potential side effects of Orlistat?
Side effects may be similar to steatorrhea.
p.31
Lipid Digestion Process
Where does fat digestion begin?
In the mouth by lingual lipase.
p.6
Classification of Dietary Lipids
What characterizes saturated fats?
They have the maximum number of hydrogens on the chain.
p.18
Lipid Digestion Process
Which lipases are present in the stomach?
Lingual lipase and gastric lipase.
p.7
Sources of Dietary Fats
Which oils are high in monounsaturated fats?
Olive, peanut, and canola oils.
What happens to cholesterol after it is absorbed?
It is esterified in the cell.
p.9
Classification of Dietary Lipids
What effect does hydrogenation have on the configuration of fatty acids?
It converts natural cis configuration to all trans.
p.27
Chylomicron Formation
Where are apo-proteins synthesized?
In the rough endoplasmic reticulum (RER).
p.2
Role of Fats in Nutrition
How do fats contribute to food flavors?
They act as carriers for food flavors.
p.3
Sources of Dietary Fats
What vitamins are animal fats good sources of?
Fat-soluble vitamins A and D.
p.30
Pharmaceutical Interventions for Fat Malabsorption
How does Orlistat affect fat absorption?
By preventing TAG digestion.
p.31
Classification of Dietary Lipids
What is TAG made up of?
Glycerol and fatty acids.
p.31
Disorders of Lipid Digestion and Absorption
What are some causes of disorders in lipid digestion and absorption?
Steatorrhea, insufficient bile, and insufficient pancreatic enzymes.
p.28
Disorders of Lipid Digestion and Absorption
What is steatorrhea?
A condition characterized by high amounts of fat in the stool due to fat malabsorption.
p.20
Lipid Digestion Process
What are the products of the hydrolysis of TAG by pancreatic lipase?
Free fatty acids (FFA) and 2-monoacylglycerol (2-MAG).
Where are digestion products primarily absorbed?
In the duodenum and jejunum.
p.30
Pharmaceutical Interventions for Fat Malabsorption
What is Orlistat used for?
It inhibits gastric and pancreatic lipase to reduce fat absorption.
p.30
Pharmaceutical Interventions for Fat Malabsorption
What is Olestra?
A synthetic fat known as octa-acyl sucrose.
p.1
Sources of Dietary Fats
What are the principal sources of fat in the diet?
Red meat, other meat, dairy products, and oils.
p.31
Lipid Digestion Process
What enzymes act in the small intestine for fat digestion?
Pancreatic lipase, pancreatic esterase, and cholesterol esterase.
What effect do plant sterols have on cholesterol absorption?
They compete with cholesterol, reducing its absorption.
p.29
Disorders of Lipid Digestion and Absorption
What are the characteristics of stools in steatorrhea?
Stools may be greasy and foul-smelling.
p.28
Disorders of Lipid Digestion and Absorption
How can gastric acid secretion affect lipid absorption?
Hypersecretion of gastric acid can prevent achieving near-neutral duodenal pH, affecting absorption.
p.29
Disorders of Lipid Digestion and Absorption
What does stool containing large amounts of TAG indicate?
Decreased absorption of fat and fat-soluble vitamins.
p.31
Essential Fatty Acids
What are the three essential fatty acids?
Linoleic, linolenic, and arachidonic acids.
