Lipids (fats and oils)

Lipids contain the same three elements of carbohydrates (carbon, hydrogen, oxygen)

• proportion of oxygen in a lipid is much lower than a carbohydrate
• Tristearin (C₅₁H₉₈O₆) - Fat found in Beef and Lamb
• Most animal fats are solid at room temperature, melts if you warm it up
• Plant lipids are usually liquid at room temperature
• Plant lipids = oils

Food rich in animal fats:

• Meat
• Butter
• Cheese
• Milk
• Eggs
• Oily fish
• Foods fried in fat or oil

Plant oils used for cooking:

• Olive oil
• Corn oil
• Rapeseed oil

Products made from oils (eg. margarine)

Lipids make up about 10% of our body's mass

• They form a part of the structure of cells.
• Fat is deposited in some parts of the body as a long-term store of energy (eg. heart, kidneys, under the skin)
• Fat layer under the skin acts as insulation
• Fat around organs helps to protect them from mechanical damage (eg. kidneys)

Chemical 'building blocks' of lipids are two types of molecule

Glycerol and fatty acids

Glycerol = oily liquid (also known as glycerine and used in cosmetics)

One glycerol molecule is attached to three fatty acid molecules

There are many different types of fatty acid and they give us many different kinds of lipid found in food

Too much lipid is unhealthy (but it is an essential part of our diet)

saturated fat and a lipid compound called cholesterol have been linked to heart disease