What are lipids?  main component in every living cell.  Organic  have carbon chains with attached hydrogen atoms and a carboxyl group at one end. FAT CELL

Made up of C, H, O, just like carbs  So what’s the difference? STRUCTURE!

Use of lipids in the body  1. Energy- 2 x energy of Carbs  2. Fat storage – energy for later use  3. Shock absorbers for the vital organs

4. Satiety value – makes us feel full longer 5. converted to other compounds- hormones, bile, Vitamin D 6. Insulates – a fat blanket under the skin

Three categories of Lipids  Triglycerides – fats & oils  Phospholipids – emulsifiers, component of cell membrane  Sterols – bile, hormones, cholesterol

Triglycerides

Forms of Triglycerides  Animal sources  Butter  Lard  Eating different types of triglycerides can have different effects on the body.  Plant sources  Margarine  Oils  shortening

Fat per day  30 % of your calorie intake or less intake or less 9 calorie per gram

 Women 19-49yrs 65 gms 16 tsp  Men gms 22 tsp  gms 15  1 tsp = 4 gms fat

 Fats and oils are made from glycerol and fatty acids.  Each glycerol is attached to 3 fatty acids.  They contain carbon, hydrogen and oxygen

Carboxyl group -COOH

 Each fatty acid consists of a hydrocarbon chain with a carboxyl group at one end. carboxyl groupcarboxyl group  The glycerol molecule has three hydroxyl groups (OH), each able to interact with the carboxyl group of a fatty acid. hydroxyl groupshydroxyl groups

Essential Fatty Acids  Those the body must get through food.  Can not make these in our bodies.

Saturated fats  Animal sources  Fatty acids are saturated-hold all the hydrogen atoms they can.  Solid at room temperature  We make our own.

Sources  Animal products

Unsaturated fats  Most of the fatty acids are unsaturated  have one or more double bonds between their carbon atoms.  2 carbon atoms missing a hydrogen bond join together  unsaturated because they could hold more hydrogen atoms than they do.

 Monounsaturated - lacks 2 hydrogen- has one double bond  Polyunsaturated- lacks more than 2 hydrogen- 2 or more double bonds

Monounsaturated fat

Polyunsaturated fat

 This prevents the fatty acids from packing close together and as a result, unsaturated fats have a lower melting point than do saturated fats. (they are healthier for you!)

Trans fatty acids Unsaturated fatty acids - one of two shapes — "cis" and "trans." refers to physical positioning of hydrogen atoms around carbon chain. cis form is more common found in small amounts in various animal products such as beef, pork, lamb and the butterfat in butter and milk.

Omega fatty acids  unsaturated fatty acids  first double bond counting from the opposite end from the carboxyl group.  terminal carbon atom (shown here in blue) is called the omega carbon atom.  monounsaturated fatty acid with its single double bond after carbon #3 (counting from and including the omega carbon) is called an omega-3 fatty acid.  But so is a polyunsaturated fatty acid, such as linolenic acid (shown here), if its first double bond is in that position.

Some studies have suggested that omega-3 fatty acids help protect against cardiovascular disease. This is known as Good Fat

Omega-6 Fatty acids  Omega-6 fatty acids belong to a group of "good" fats called polyunsaturated fatty acids.  Help with immune system  Relax Good dietary sources of omega-3 fatty acids

Hydrogenated Vegetable oil  In hydrogenation, plant oils are exposed to hydrogen at a high temperature and in the presence of a catalyst, and turned from liquid into solid!

 Occur when hydrogenation is done the unsaturated fats become saturated  Hardened margarines

 Good- Makes them resistant to oxidation- become rancid more slowly  Good- makes them more stable  Bad- makes them more saturated

Functions of Triglycerides in Food  Flavor – make foods taste better  Tenderize  Emulsifiers  Aeration – traps air in bubbles

Rancidity  Oxidation of fat  Fatty acids combine with oxygen and lose hydrogen  Unsaturated fats with more double bonds are more prone to oxidation  heat, light and oxygen speeds up oxidation

 Rancid is the term that describes the unpleasant flavors that develop as fats oxidize  Different chemical changes occur for different types of fats  Rancid nuts, meats and potato chips all taste different

Phospholipids  Can dissolve in both fat and water  Used as emulsifiers  Found in eggs and peanuts  Main component of cell membranes

Sterols A fatty alcohol made from glucose or saturated fatty acids

strengthens cell membrane strengthens cell membrane precursor of other steroids, including sex hormones. precursor of other steroids, including sex hormones. Vital for producing Vitamin D Vital for producing Vitamin D  Used to make bile

 Your liver produces all the cholesterol you need.  Cholesterol in foods is useless  It can make plaque which builds up on the walls of blood vessels

LDL = low density lipoprotein (bad)  Carries cholesterol to to the body tissues to deposit there  When elevated forecast heart and artery disease  Oxidation of LDL causes damage to arteries

Antioxidants  Slows oxidation of LDL  Vitamin C, Vitamin E, selenium are antioxidants

HDL = high density lipoprotein (good)  HDL cholesterol- carries cholesterol away from tissue

Olestra- artificial fat  Remains undigested  Passes through the digestive tract intact  Causes diahrea and digestive upset  Does not allow vitamins to be absorbed by the body