Intro to Nutrition chapter 5 Lipids.
Plaque
A deposit of fatty material on the inner lining of an arterial wall
saturated fats
A fat that is solid at room temperature and found in animal fats, lards, and dairy products.
Chylomicron
A large lipoprotein that is used to transport fat (long-chain) from a meal.
Systolic
Blood pressure in the arteries during contraction of the ventricles. (The numerator of the blood pressure)
emulsification
Breakdown of large fat globules into smaller, digestible particles.
When does the body initiate fat usage.
Can occur just after 20 minutes of exercise.
How can fatty acids differ?
Carbon chain length. Degree of saturation Shape
Lipids
Composed of fats (solid) and oils (liquid) are a family of organic coumpounds that are mostly insoluble in water.
Carbon chain length
Determines the method of digestion, absorption and transport int he body. Foods have fatty acids with chain lengths between 4 and 24 carbons.
Lipoproteins
Formed from triacylglycerols, cholesterol and phospholipids with a protein carrier.
Where are triglycerides found?
Fried foods, vegetable oil, butter, whole milk, cheese, corn, nuts, olives and some meats.
trans fatty acids
Hydrogen atoms are attached on opposite sides of the carbon chain. Trans fats can negatively impact blood cholesterol levels.
cis fatty acids
Hydrogens on same side at the double bond; most natural fats and oils
triacylglycerol
Make up more than 95% of lipids int he diet.
What else can triglycerides be used for.
Making lipid containing compounds needed buy the body.
adipose tissue
Tissue that stores fat and excess calories
AMDR for lipids
Total Fat: 20-35% of total calories Saturated fat: <10 Trans fat: minimize. Cholesterol: Minimize Omega3: 0.6-`/2 Omega-6: 5-10
Intermediate-density lipoproteins
Transport a variety of fats and cholesterol int the bloodstream. <50% triacylglycerol composition Gains cholesterol from other lipoproteins during circulation -Upon returning to the liver they are converted into LDLs.
Characteristics of VLDLs
Transport triacylglycerols from the liver to various tissues in the body. -As lipoprotein lipase removes triacylglycerol from VLDL they convert into IDLs
Body storage of fat as carbohydrates
When the muscles reach their capacity for glycogen storage, the excess is returned to the liver where it is converted into triaglycerols and then stored as fat..
Atherosclerosis
condition in which fatty deposits called plaque build up on the inner walls of the arteries
Where do 30-70% of the energy used during rest comes from?
fat
Visceral fat
fat located around major organs
Subcutaneous fat
fat stored directly under the skin. Helps with temperature control.
essential fatty acids
fats needed by the body that must be consumed in the diet because the human body cannot manufacture them
Hypertension
high blood pressure
short chain fatty acids
less than 6 carbons
omega-3 fatty acids
polyunsaturated fatty acids commonly found in fish oils that are beneficial to cardiovascular health. The 3 is the position of the first carbon double bond.
Diastolic
pressure within the walls of arteries when the left ventricle is at rest. (The denominator of the blood pressure).
Thrombus
stationary blood clot
What fats are healthy?
unsaturated fats (both poly and mono)
VLDL
very low density lipoprotein
digestion of lipids in small intestine
-Bile is imperative to the digestive process of lipids. -Bile contains bile salts, lecithin, and substances derived from cholesterol, so it acts as an emulsifier. -Emulsification increases the surface area of lipids making them more accessible to the digestive enzyme. -Once emulsified, fat-breaking enzymes work on the triacylglycerols and diglycerides to cleave fatty acids from glycerol. Pancreatic lipase breaks down the fats into free-fatty-acids and monoglycerides. Bile salts help fats pass through the battery layer of mucous that coats the absorptive lining of the digestive tract. -Bile salts envelop the fatty acids into and monoglycerides to form micelles. -Micelles transport the end products of lipid digestion to the digestive tract lining for absorption. Micelles have a fatty acid core with a water soluble exterior which allow for efficient transportation to the intestinal microvillus. Fat components are released and disseminated into the cells of the digestive tract lining.
Digestion of lipids
-In the mouth, chewing and the enzyme lingual lipase along with a small amount of phospholipid as an emulsifier, initiates the process of digestion. -In the stomach, gastric lipase starts to break down triaglycerols into diglycerides and fatty acids. -Within 2-4 hours after eating a meal, roughly 30# of the triacyglycerols are converted to diglycerides and fatty acids. -Churning and contractions int eh stomach help to disperse the fat molecules, while the diglycerides derived in this process act as a further emulsifier.
Sterols
-Least common type of lipid. -Cholesterol is the most common sterol in the diet. -Body produces most of its cholesterol, however, a small amount does come from the diet. -Cholesterol is an important component of the cell membrane and is required for the synthesis of sex hormones, vitamin d and bile salts. -Most sterols do not contain any fatty acids but rather are multi-ring structures. -Complex molecules that contain interlocking rings of carbon atoms with side chains of carbon, hydrogen, and oxygen.
Phospholipids
-Make up about 2% of dietary lipids -Water-soluble and are found in both plants and animals. -Found in the body so not an essential nutrient. -Crucial for building the protective barrier or membrane around your body cells. -Phospholipids are diglycerides while their third fatty-acid chain has a phosphate group. -Amphiphilic: fatty acid sides are hydrophobic (dislike water) and the phosphate group is hydrophilic (likes water) -In blood and body fluids, phospholipids form structures in which fat is enclosed and transported throughout the bloodstream. Phospholipids are ideal emulsifiers that keep oil and water mixed.
When do muscle cells use fatty acids for work.
-When energy requirements exceed the available fuel from a recent meal or physical activity has exhausted glycogen reserves. -When additional energy is needed, the adipose tissue dismantles its triacylglycerols and dispenses glycerol and fatty acids directly into the blood to be taken up by cells and broken down for energy.,
Lipid digestion process
1. Chewing and saliva begin the digestion of fats. 2. Stomach turns triacylglycerols into diglycerides and fatty acids. 3. Small intestine combines bile with separated fats.
long chain fatty acids
14-24 carbons
medium chain fatty acids
6-12 carbons
Energy per gram of lipids
9 kcal/gram
What compound do omega 3 and 6 give?
Eicosanoids
Blood Cholesterol Recommendations
Elevated LDL increases risk of heart attack Elevated HDL reduces risk of heart attack
Functions of lipids
Energy reserve, regulate hormones, transmit nerve impulses, cushion vital organs, transport fat-soluble nutrients. -Fat in food serves as an energy source with high caloric density, adds texture and taste, and contributes to satiety.
monounsaturated fats
Fats help regulate blood cholesterol levels thereby reducing the risk of heart disease and stroke.
Building blocks of triacylglycerols
Fatty acids and glycerol. Glycerol molecule is joined by 3 fatty acid chains. Glycerol is a 3 carbon alcohol that is the backbone of triacylglycerol Various fatty acids attach to the glycerol backbone.
Polyunsaturated fats
Fatty acids with 2+ double bonds or 2+ points of unsaturation (soybean oil)
Where should most fats come from?
Monounsaturated, polyunsaturated, and omega-3 fatty acids.
Body storage of fat as fat
Much of the triacylglycerols th body receives from food is transported (via chylomicrons) to fat store houses within the body if not used for producing energy.
Fat soluble nutrients
Require fat for effective absorption -Vitamins A,D,E,K are best absorbed with foods containing fat.
optimal blood pressure
Systolic <120 Diastolic <80
What happens when the carbon chain is shorter in a fatty acid.
The melting point of the fatty acid becomes lower (the fatty acid becomes more liquid.
Point of unsaturation
The place on the chain where a hydrogen atom is missing.
Hydrogenation
The process of converting unsaturated fats to saturated fats by adding hydrogen
Chylomicron transport
Transported from the intestinal lining to the lymphatic system and released into the bloodstream via the jugular vein in the neck. -Chylomicrons transport food fats through the body water based environment to specific destinations scubas th deliver and other body tissues. -Short and medium chain fatty acids are absorbed more quickly since they are not arranged into chylomicrons. Cholesterols are poorly absorbed when compared to phospholipids and triacylglycerols. . Cholesterol absorption is hindered by fiber.
High-density lipoprotein (HDL)
blood fat that helps transport cholesterol out of the arteries, thereby protecting against heart disease. (Good cholesterol)
low-density lipoprotein (LDL)
blood fat that transports cholesterol to organs and tissues; excess amounts result in the accumulation of fatty deposits on artery walls. Bad cholesterol
Embolus
moving blood clot
blood pressure
the pressure that is exerted by the blood against the walls of blood vessels
3 main types of lipids
triglycerides, phospholipids, sterols
