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