FATS OILS What are Fats Fats are substances

FATS & OILS

What are Fats ? Fats are substances that help the body use some vitamins and keep the skin healthy; they are also the main way the body stores energy. Fats are high in calories and they are hidden in some of the foods we eat regularly e. g. chocolates, biscuits and chips. Excess fat is stored in the adipose tissue and can be used as an energy source, also they protect certain organs like the kidneys. Fats are also referred to as lipids.

The lipid family consist of 1. Triglycerides 2. Phospholipids 3. Sterols A triglycerides are made up of Carbon Oxygen Hydrogen, oxygen and carbon makes up a molecule of glycerol and fatty acids which when combine makes up a Fat molecule. Triglycerides is the most common lipid found in food and the body.

Difference between Fats and Oils Fats and oils have the same basic structure but their physical structure at room temperature differs. Fats are solid at room temperature while oils are liquid at room temperature.

Types of Fats Saturated Found in animal products Unsaturated Found in plant oils They have the maximum possible There are two types of number of hydrogen atoms hence the unsaturated fats name ‘Saturated”. 1. Monounsaturated Sources 2. Polyunsaturated 1. Meat Sources 2. Butter 1. Fish 3. Ghee 2. Nuts and Seeds 4. Full Fat cheeses 3. Avocado 4. Olive oil and vegetable oils

Unsaturated Fats MONOUNSATURATED Monounsaturated fats may be healthier choice as research shows that they can lower blood cholesterol levels. Therefore lowering the risk of developing cardiovascular diseases Sources 1. Olive oil 2. Canola Oil 3. Rapeseed Oil POLYUNSATURATED Polyunsaturated fats are found in 1. Sunflower oil 2. Vegetable Oils 3. Walnuts 4. Sunflower seeds 5. Oily fish(tuna, sardines and Marcels)

Unsaturated Fats- the body can make the fatty acids it need except for two EFA essential fatty acids known as Alpha linolenic acids used for cell membranes and nerve tissue, these are: Linolenic Acid (Omega 3) Sources 1. Oily fish 2. Salmon 3. Macreles 4. Fish oil supplements 5. Flaxseeds Linolelic Acid (Omega 6) Sources 1. Vegetables oils 2. Nuts 3. Seeds

Trans fats are another type of unsaturated fat. This fat has the similar effect as saturated fats which can raise your LDL cholesterol and lower the amount of HDL cholesterol. Trans fats are produced when liquid oil are processed turning them into solid fats (butter, margarines) through Hydrogenation. Fully hydrogenated fats contains not trans fats but partially hydrogenated fats will contain trans fats.

Sterols -Cholesterols Sterols have a different structure from other lipids A well known sterol is cholesterol another important sterol is cortisone from the adrenal gland , sex hormone (oestrogen) Vitamin D and bile acid. Cholesterol is a waxy substance found in all body cells. It is made in the liver daily and is used for important functions like maintain cell membranes, forming bile salts and producing hormones. Cholesterol isn’t found in plant products.

Types of Cholesterol High- Density Lipoprotein (HDL) Is known as the “Good” Cholesterol. This Lipoprotein is good for picking up excess cholesterol from in the blood and take it to the liver where it is broken down. Sources Low- Density Lipoprotein (LDL) carries cholesterol around the body but can result in a build up inside the blood vessels. In a sticky layer called plaque and can lead to heart disease. Build up of plaque is called atherosclerosis which leads to heart attack, stroke and eventually death. Sources –organ meat, egg yolks, shell fish, poultry, fish and dairy products

Visible and Invisible Fats Visible fats are fats that are easy to detect in food. e. g. Fats on meats Invisible Fats Makes up parts of the food and are very difficult to detect. e. g. Butter Lean meats Margarine egg yolk Lard Flesh of oily fish Suet Nuts, seeds, fruits Cooking fats and oils Prepared foods e. g pastry , cakes, biscuits, fried foods.

Functions Provides a concentrated source of energy. Supplies more energy than protein and carbohydrates. Surrounds and protects vital organs. Forms an insulated layer (adipose tissue) to provide heat. Forms part of the structure of the cell membranes throughout the body especially the brain. Provides a source of Fat soluble vitamins ADEK. Provides reserved energy which can be used if energy intake is restricted. Provides texture and flavour in foods. Provides a feeling fullness (satiety) after meals because fat is digested slowly.

Sources of Fats ANIMAL PLANT

Reducing Fats in the diet There are many way to reduce the amount of saturated fats in the diet. 1. Avoid frying and roasting foods 2. Eat lean cuts of meat 3. Remove fat from meat 4. Eat skin less chicken 5. Use low fat dairy products 6. Use reduce fat or low fat spreads.

Requirements of fats in the diet

Digestion of Fats Lipids, or fat, go undigested in your digestive tract until they reach your small intestine, where they meet bile. Bile contains bile salts, which act as an emulsifier of lipids. This breaks the large fat droplets into smaller droplets that are then easier for the fat-digesting enzyme pancreatic lipase to digest.

Effects of heat on Fats As fats are heated they melt and become liquid oils. As heating continues the oils become thinner and begins to bubble. At very high temperatures fat molecules begin to decompose into glycerol and fatty acids. A blue haze is seen then smoke after this fat ignites and burns. Fat soluble vitamins are not affected by heat.

Home Work 1. What are the functions of fat in the body ? 2. What is the difference between fats and oils ? 3. What chemical elements make up fats ? 4. How are fat molecule composed ? 5. Name four plant sources and four animal sources of fats. 6. What is the difference between invisible fats and visible fats? 7. Name three saturated and three unsaturated fatty acids ? 8. Why is an excess intake of fat undesirable ? 9. What factors are associated with coronary heart disease ? 10. Describe the effects of heat on fats ? 11. What are essential Fatty acids ? 12. How does breast feeding help to make sure babies get EFAs in their diet ?