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Lipids
Lipids (Fats)
Lipids are a group of substances that are relatively insoluble in water
Some of these substances include: Triglyceride = 95% of all Fats (body fat)
Cholesterol (a fat-like compound occurring in bile, blood, brain and nerve tissue, liver and other parts of the body) Steroid hormones, Transport of Fat, Cell Membranes, Component of Cells
Lipids (Fats)
Phospholipids such as Lecithin Cell membranes, Transport of Fat
Vitamins A, D, E, K
Bile acids
Function of Dietary Fats
Provide taste/flavor qualities to foods
Provide fat soluble nutrients
Provide energy in a concentrated form
Provide satiety
Function of Body Fat
Provides a storage form of energy
Provides insulation
Provides protection to internal organs
Provides fat for lactation
Triglycerides 95 % of all fat in Nature, including dietary Fat
and Body Fat
Stable condition of Fat for storage
Breaks down during digestion so Free Fatty acids can be absorbed
The Chemist’s View of Fatty Acids and Triglycerides Triglycerides are lipids with three fatty acids
attached to a glycerol.
Lipids (Fats)
A Fat (Based on it’s composition of Fatty Acids) is classified as
Saturated, or Unsaturated
Saturated and unsaturated fats are made up of fatty acids (saturation refers to the number of hydrogen atoms in the fatty acids)
Lipids (Fats)Saturated Fats
A saturated fat acid carries all the hydrogen atoms it can;
Fatty Acids:
Saturated Fatty acids
Lipids (Fats)Saturated Fats
saturated fats are found in whole milk, egg yolks, meat, meat fat, coconut and palm oils, chocolate, margarine, and hydrogenated vegetable oils
Something to Think About
What disease did cured ham actually have?
Unsaturated fats are derived from plants Monounsaturated fats are found in olive oil
and some nuts
Fatty Acids: Unsaturated fatty acids
Polyunsaturated fats are found primarily in safflower, cottonseed, corn, soybean, and sesame seed oils; salad dressing made from oils; and fatty fish
Fatty Acids: Unsaturated fatty acids
Stearic acid, an 18-carbon saturated fatty acid
Oleic acid, an 18-carbon monounsaturated fatty acid
Linoleic acid, an 18-carbon polyunsaturated fatty acid
Excuse me but which is the one that practically Kills you…..polysaturated or polyunsaturated?
Polyunsaturated fats are found primarily in safflower, cottonseed, corn, soybean, and sesame seed oils; salad dressing made from oils; and fatty fish
There are Two different types of Polyunsaturated Fatty Acids.
Omega-3-Fatty Acids
Omega-6-Fatty Acids
Fatty Acids: Unsaturated fatty acids
The Chemist’s View of Fatty Acids and Triglycerides Polyunsaturated Fatty Acids
The Location of Double Bonds The omega number refers to the position of the first
double bond.
An omega-3 fatty acid has the location of the double bond in the third position from the end carbon. An example is linolenic acid.
An omega-6 fatty acid has the location of the double bond in the sixth position from the end carbon. An example is linoleic acid.
Linoleic acid is the only essential dietary lipid; it is found in safflower, sunflower, and corn
Essential fatty Acids
Omega-3 fatty acids
Omega-3 fatty acids are Polyunsaturated Fatty acids classified as essential because they cannot be synthesized in the body; they must be obtained from food.
Important omega-3 fatty acids in human nutrition are: α-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA).
Omega-3 fatty acids
Health benefits U.S. FDA gave "qualified health claim" status
to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) omega-3 fatty acids, stating that "supportive but not conclusive research shows that consumption of EPA and DHA omega-3 fatty acids may reduce the risk of Coronary Heart Disease
Omega-3 fatty acids
Omega-3 fatty acids Fish oils and plant oils are the primary dietary
source of omega-3 fatty acids. Another potential source of omega-3 fatty acids is
New Zealand green lipped mussels. EPA and DHA are found in cold-water fish such as
salmon, mackerel, halibut, sardines, and herring. ALA is found in flaxseeds, flaxseed oil, canola
(rapeseed) oil, soybeans, soybean oil, pumpkin seeds, pumpkin seed oil, purslane, perilla seed oil, walnuts, and walnut oil
Fats-Dietary Guidelines
Keep total fat intake between 20 to 35 percent of total calories Most from poly and mono fatty acids (fish,
nuts, vegetable oils, etc.) Consume < 10% of calories from
saturated fatty acids, Consume < 300 mg/day of cholesterol, Keep trans fatty acid consumption low
Fats-Dietary Guidelines
Eat lean, low-fat, or fat-free meat, poultry, dry beans, and milk or milk products
Limit intake of fats, oils, and products high in sat/trans fatty acids
Diets high in cholesterol and saturated fat are believed to increase the risk of coronary heart disease, some cancers and obesity
Polyunsaturated fatty acid (PUFA) polyunsaturated fats tend to lower blood cholesterol
Fats and Health Concerns
The Chemist’s View of Fatty Acids and Triglycerides Degree of Unsaturation Revisited
Firmness Saturated fats are solid at room temperature. Polyunsaturated fats are liquid at room temperature. Shorter fatty acid chains are softer at room temperature
than longer chains.
Something to Think About
If the professor on Gilligan's Island can make a radio out of a coconut, why can't he fix a hole in a boat?
The Chemist’s View of Fatty Acids and Triglycerides Degree of Unsaturation Revisited
Stability Saturated fat is more resistant to oxidation. Monounsaturated fat is slightly less susceptible to
spoilage. Polyunsaturated fat spoils most readily. Protection from rancidity
Sealed in airtight containers away from light Add antioxidants Hydrogenation
The Chemist’s View of Fatty Acids and Triglycerides Degree of Unsaturation Revisited
Hydrogenation Protects against oxidation therefore prolonging shelf life Alters texture
Trans-Fatty Acids Changed from cis to trans configuration and act like
saturated fats in the body Heart disease connection is being researched. Conjugated linoleic acid is a naturally occurring trans fat
that may be beneficial to health.
What is Trans Fat?
Basically, trans fat is made when manufacturers add hydrogen to vegetable oil--a process called hydrogenation.
Hydrogenation increases the shelf life and flavor stability of foods containing these fats.
Trans fat
Trans fat can be found in vegetable shortenings, some margarines, crackers, cookies, snack foods, and other foods made with or fried in partially hydrogenated oils. Unlike other fats, the majority of trans fat is formed when food manufacturers turn liquid oils into solid fats like shortening and hard margarine.
Trans fat
Trans fat, like saturated fat and dietary cholesterol, raises the LDL cholesterol that increases your risk for CHD.
Americans consume on average 4 to 5 times as much saturated fat as trans fat in their diets.
The Chemist’s View of Phospholipids and Sterols Phospholipids and sterols have unique
chemical structures that allow them to have unique roles in the body.
Sterols have a multiple-ring structure.
The Chemist’s View of Phospholipids and Sterols Phospholipids
Phospholipids in Foods Phospholipids contain glycerol, two fatty acids and a
phosphate group with a molecule of choline. Used as emulsifiers in food industry A well-known phospholipid is lecithin. Food sources of lecithin include eggs, liver, soybeans,
wheat germ and peanuts.
Do the Alphabet song and
Twinkle, Twinkle Little Star have the same tune?
Do the Alphabet song and
Twinkle, Twinkle Little Star have the same tune?
Did you just try singing the two songs above?
The Chemist’s View of Phospholipids and Sterols Roles of Phospholipids
Enable transport of lipids across cell membranes
Emulsifiers
Lechithin is made by the liver. Supplements increase energy intake and can cause GI symptoms.
The Chemist’s View of Phospholipids and Sterols Sterols – A well-known sterol is cholesterol.
Sterols in Foods Found in plant and animal foods Cholesterol is found in animal foods only—meat, eggs,
fish, poultry and dairy products (exogenous).
The Chemist’s View of Phospholipids and Sterols Sterols
Roles of Sterols Starting material for bile acids, sex hormones, adrenal
hormones and vitamin D Structural component of cell membranes Liver produces 800-1500 mg cholesterol per day
(endogenous). Atherosclerosis is a disease that causes heart attacks. It
occurs when cholesterol forms deposits in the artery wall.
Transport of Lipids
Lipid transport is made possible by a group of vehicles known as lipoproteins. Chylomicrons
Largest of the lipoproteins Least dense Get smaller as triglyceride portion is removed by the
cells
Transport of Lipids
Lipid Transport VLDL (Very-Low-Density Lipoproteins)
Composed primarily of triglycerides Made by the liver Transport lipids to the tissues Get smaller and more dense as triglyceride portion is
removed
Transport of Lipids
Lipid Transport LDL (Low-Density Lipoproteins)
Composed primarily of cholesterol Transport lipids to the tissues
HDL (High-Density Lipoproteins) Composed primarily of protein Transport cholesterol from the cells to the liver
Transport of Lipids
Lipid Transport Health Implications
High LDL is associated with higher risk of heart attack and is known as “bad” cholesterol.
High HDL seems to have a protective effect and is known as “good” cholesterol.
Transport of Lipids
Lipid Transport Health Implications
Factors that lower LDL and raise HDL Weight control Replace saturated fat with monounsaturated fat and
polyunsaturated fat in the diet Soluble fibers Phytochemicals Moderate alcohol consumption Physical activity
Genes influence lipoprotein activity.
Two types of blood cholesterol Low-density lipoproteins (LDL)
sometimes referred to as “bad” cholesterol, causes cholesterol to build up on the walls of your arteries increasing your risk of heart disease
LDL Cholesterol-Recommended Range
Very high LDL level, corresponding to highest increased risk of heart disease
>4.9>190
High LDL level4.1 to 4.9160 to 189
Borderline high LDL level3.3 to 4.1130 to 159
Near optimal LDL level2.6 to 3.3100 to 129
Optimal LDL cholesterol, corresponding to reduced, but not zero, risk for heart disease
<2.6<100
InterpretationLevel mmol/LLevel mg/dl
Two types of blood cholesterol
High-density lipoproteins (HDL) sometimes referred to as “good” cholesterol, helps your body get rid of cholesterol in your blood; the higher your HDL the better as it helps reduce the risk of heart disease
Hyperlipidemia
After 12 Weeks of Exercise
*Total Cholesterol -- decreases
*HDLs -- increase
*LDLs -- decrease
This is the left coronary artery from the aortic root on the left. Extending across the middle of the picture to the right is the anterior descending branch. This coronary shows severe atherosclerosis with extensive calcification..
This aorta shows severe atherosclerosis
Fats-Dietary Guidelines Keep total fat intake between
20 to 35 percent of total calories Most from poly and mono fatty acids
(fish, nuts, vegetable oils, etc.)
Consume < 10% of calories from saturated fatty acids,
Consume < 300 mg/day of cholesterol, Keep trans fatty acid consumption low
YOU WANT BY-PASS SURGERY
WITH THAT
LDL Cholesterol- Recommended Range
Very high LDL level, corresponding to highest increased risk of heart disease
>4.9>190
High LDL level4.1 to 4.9160 to 189
Borderline high LDL level3.3 to 4.1130 to 159
Near optimal LDL level2.6 to 3.3100 to 129
Optimal LDL cholesterol, corresponding to reduced, but not zero, risk for heart disease
<2.6<100
InterpretationLevel mol/L
Level mg/dl