Nutrition Ch. 5 The Lipids

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What is a Lipid?
A bamily of organic (carbon containing) compounds soluble in organic solvents but not in water.
Name 3 types of Lipids
Triglycerides (fats and oils)
What is Cholesterol?
A member of the group of lipids known as sterols .
A soft waxy stubstance made in the body for a variety of puposes and also found in animal derived foods.
What are Fats?
Lipids solid at room temperature
What are oils?
Lipids that are liquid at room temperature.
What is cardiovascular disease? (CVD)
Disease of the heart and blood vessels.
Disease of the heart is also called coronary heart disease. (CHD)
What are Triglycerides?
Tryglycerides - one of three main classes of dietary lipids and the chief form of fat in foods and in the human body.
What are Triglycerides made up of?
What is another name for them?
1. Triglycerides are made of 3 units of fatty acids and one of glycerol.
2. Triglycerids are also called Triaglycerols .
What percentage of body fat are Triglycerides?
What is the chief form of storage in the body for energy eaten in excess of need?
What provides most of the bodys energy for work, especially muscular work?
What are fat tissues called?
Adipose tissues
What do adipose (fat) tissues do?
Adipose tissues secrete hormones that help regulate appetite and influence other body functions in ways critical to good health.
How is lipid stored in a fat cell?
Lipid is stored in a fat cell as a droplet.
This can greatlh expand to accomodate swollen contents.
How do the storage mechanisms differ between fats and glycogen?
Fats can store more energy tightly together in a small place without water.
1.What is a function of fat in terms of vital organs?
2. The bodys cells?
1. Fat protects vital organs (cushioning)
2. lipds play critical rolse in all the body's cells as a part of their surrounding envelopes, the cell membranes.
How do fats and carbohydrates compare energy-wise?
Gram for gram fats store more than twice the energy compared to carbohydrates.
What affect does fat have on some nutrients?
Some nutrients are soluble in fat and therefore found in foods that contain fat and are absorbed more efficiently from them.
Name 4 fat soluble vitamins.
A,D, E, K
What are essential fatty acids?
Fatty acids that the body needs but cannot make to mee physiological needs.
What are the two main ways fatty acids differ from each other?
1. chain length
2. degree of saturation
What is Glycerol?
Glycerol = organic compound, 3 carbons long.
Servesa as the backbone of triglycerides.
How are fatty acids made atomically?
Each fatty acid has and acid end and hydrogen attached to all of the carbon atoms of the chain.
What affects the melting point of fatty acids?
1.The degree of saturation of fatty acids in a fat affect the temp at which the fat melts.
2.The more saturated, the firmer it is at room temp.
3.The more unsaturated, the more liquid it is.
What is a saturated fatty acid?
Fatty acid carruying the maximum possible number of hydrogens.
Point of Unsaturation
A site in a molecule where the bonding is such that additional hydrogen atoms can easily be attached.
What is an unsaturated fatty acid?
A fatty acid that lacks some hydrogen atoms and containins one or more points of unsaturation.
What is a monounsaturated fatty acid?
Triglycerides in which most of the fatty acids have one point of unsaturation (monsaturated)
What is a polyunsaturated fatty acid?
A triglyceride in which most of the fatty acids have two or more points of unsaturation (polyunsaturated)
What two types of oils are rich in polyunsaturated fats?
Vegetable and fish oils are rich in polyunsaturated fats.
What types of fats are generally the most saturated?
Animal fats.
What types of plant-based oils are also high in saturated fat?
Coconut oil, palm oil. and vegetable oils used in food processing.
What are phopholipids?
Phospholipids = A molecule of glycerol with fatty acids attached, but contains 2, rather than 3, fatty acids.
What do phospholipids do? (3 things)
1. Phospholipids help fats travel back and forth across the lipid containing membranes of cells in the watery fluids on both sides.
2. They bind together to form cell membranes.
3. serves as an emulsifier
Why are phospholipds such good emulsifiers?
in place of the 3rd is a molecule containing phospherous which makes the phospholipid soluble in water, while it's fatty acids make it coluble in fat.
This versatility permits any phospholipid to paly a role in keeping fats dipsersed in water.
What is an Emulsification?
the process of mixing lipid with water by adding and emulsifier.
Describe how emulsifiers work in mayonaise.
Mayonnaise is made from vinegar and oil but never separates b/c it's held together by the phospholipid lecithin found in egg yolks.
What is an Emulsifier?
Substance that mixes with both fat and water and peranently disperses the fat in the water, forming an emulsion.
What are Sterols?
Sterols = large complicated molecules consisting of interconnected rings of carbon atoms with side chains of carbon, hydrogen, and oxygen attached.
What serves as a raw material for making emulsifiers in bile?
What is bile?
Bile = an emulsifier made by the liver from cholesterol and stored in the gallbladder.
What does Bile do?
Bile emulsifies fat so that enzymes in watery fluids may contact it and split the fatty acids from their glycerol absorption.
What sterol contains vitamin D?
T or F, Plant sterols help with Cholesterol absorption?
Fals - plant sterols Inhibit cholesterol absorption.
What happens to fat when it enters the small intestine?
Bile contains compunds made from cholesterol that work as emusifiers by mixing fat with water so it can be broken down by enzymes.
What is the pancreas role in digestion of fats?
The pancreas contribute fat digesting enzymes that splits fat into smaller molecules.
What happens to fats in the intestine once they are emulsified? (3 steps)
1. Fat splitting enzyme act on triglycerids to split fatty acids from their glycerol backbones.
2. Bile shuttles lipids across the intestinal barrier to waiting cells.
3. Bile may be re-absorbed by the body or excreted as feces.
What are Lipoproteins?
Lipoproteins = clusters of lipids associated with protein, which serve as transport vehicles for lipids in blood and lymph.
Name 3 things that must be converted into Lipoproteins before they can be released into the bloodstream?
Larger digested lipids
Long chain fatty acids
Lipoproteins formed when lipids from a meal are combined with carrier proteins in the cells of the intestinal lining.
What do Chlyomicrons do?
Chlyomicrons transport food fast through the watery body fluids to the liver and other tissues.
Fats need speical transport vehicles to carry them in watery body fluids. What are they?
What happens to excess glucose that is not immediately used for energy?
It is reassembled into fatty acid chains and stored.
What is carbohydrates role in the breakdown of fat?
What happens without them?
1.Carbs help the process run more efficiently
2. Without carbohydrates, products of incomplete fat breakdown (keytones) build up and spill out into urine.
What is the DRI upper intake limit for lipids?
1. DRI comittee did not set a UL for lipids
2 .Instead they reccomend no more than 20-35% of energy from total fat and recommended that trans fat, saturated fat, and cholesterol be kept low.
What are the Dietary Guidlines for saturated fat intake and what is the estimated current US intake?
DG = no more than 10%
Current US Intake = 12%
Other than Chylomicrons, 3 other types of lipoproteins carry fats, what are they?
1. Very Low Density Lipoproteins (VLDL)
2. Low Density Lipoproteins (LDL) ( bad)
3. High Density Lipoproteins (HDL) (good)
What are LDL?
Low Density Lipoproteins =
1. transport lipids from the liver to other tissues such as muscle and fat
2. contain a large amount of cholesterol
What are HDL?
High Density Lipoproteins = lipoproteins that return cholesterol from the tissues to the liver for dismantling and disposal.
They contain a large proportion of protein.
What are 3 diffrences between LDL and HDL?
1. LDL are larger, lighter, and richer in cholesterol than HDL.
HDL is smaller, denser, and packaged with more protein.

2. LDL deliver tiglycerides and cholesterol to tissues
HDL scavenges excess cholesterol and other lipoids from the tissues to the liver for disposal.

3. LDL carries lipids that trigger inflammation that may contribute to heart disease.
HDL oppose inflammatory process and protect against heart attacks.
Whad does oxidation of LDL cause?
Oxidation of LDL causes inflammation thus contributing to damage to the arteries of the heart.
1. Name 4 dietary antioxidants
2. What do they do?
1. Vitamin C, Vitamin E, Selenium, and phytochemicals.
2. Antioxidants oppose LDL oxidation
(correlates with low heart disease risk).
What raises LDL cholesterol more, Trans/Saturated Fats or cholesterol directly from food?
Most saturated food fats and trans fats raise harmful blood cholesterol more than the food cholesterol does.
What are the main dietary factors associated w/ harmful blood cholesterol levels?
Intake of Saturated Fats and Trans Fats.
What is the role of dietary cholesterol in LDL levels?
1. Dietery cholesterol still matters when it comes to LDL but Trans/saturated fats are a bigger contributer.
2. People with high LDL may benefit from less than 200mg a day intake.
1. What are linoleic and linolenic acids?
2. What do they do?
1. Polyunsaturated fatty acids that are essential nutrients for human beings.
2. Act somewhat like hormones and affect body functions like muscle relaxation and contraction, blood vessel constriction and dilation, blood clot formation, blood lipid regulation, and immune response to inj. and infection sucha s fever, inflammation and pain.
What happens with deficiencies of essential fatty acids?
Reproductive failure, skin abnormalities, kidney and liver disorders.
1. What are Omega-6 Fatty Acids?
2. What is an example?
2. polyunsaturated fatty acid w/ its endmost double bond 6 carbons from the end of the carbon chain.
2. Linoleic acid is an example.
1. What is an Omega-3 fatty acid?
2. What is an example?
1. Omega-3 fatty acid = a polyunsaturated fatty acid with it's endmost double bond 3 carbons from the end of the carbon chain.
2. Linolenic acid is an example.
What is EPA/DHA?
EPA/DHA = omega-3 fatty acids that appear to lower blood pressure, prevent blood clot formation and protect against irregular heartbeats.
What percent of the weight of the human breain is lipid?
25% of the dry weight of the human brain is lipid.
Where does human breastmilk and EPA/DHA fit in?
EPA/DHA from human breastmilk plays special roles in early development.
What makes up most of the added fat in the US diet?
Vegetable oil (fried foods)
What foods are Omega-3 fatty acids mostly commonly found?
Vegetable oils, margarine, salad dressings.
What foods are Omega-6 fatty acids found in?
reccomended weekly intake = 2 servings or 8oz.
What is Hydrogenation?
Hydrogenation = the process of adding hydrogen to unsaturated fatty acids to make fat more solid and resistant to chemical change of oxidatoin.
What 2 things does hydrogenated oil do for cuisine?
1. High smoking point so it's suitable for frying
2. Makes things creamy/spreadable.
What are Trans-fatty acids?
Trans-Fatty Acids = fatty acids that arise during the hydrogenization process.
What are two drawbacks to Trans-fatty Acids?
1. Raises LDL and lowers HDL.
2. Eliminates the health benefits of the original oil.
What are the top 3 contributers of saturated fats to the US diet? (foods)
1. Cheese
2. Beef
3. Milk
What are fat replacers?
ingredients made from carbohydrate or protein that replace some or all of the functions of fat and may or may not provide energy.
T or F, Fat Free versions of products are generally lower in calories than the origianl products.
False - fat free does not necessarily mean less calories, especially if the fats have been replaced with sugars.
What percentage of Americans eat out daily?
Where are chylomicrons produced?
small intestinal cells

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