unit 2 food and nutrition 3 eso

Unit 2 Food and nutrition

Types of Nutrients

• INORGANIC NUTRIENTS– Water– Minerals

• ORGANIC NUTRIENTS– Carbohydrates– Lipids– Proteins– Vitamins

Carbohydrates

• They are one of the main dietary components.• Classification:• Monosaccharides. • Disaccharides• Polysaccharides

Monosaccharides.

• Formed of a single molecule. They are used directly by cells.– Glucose – Fructose: Fructose is known popularly as fruit's

sugar. – Galactose– Ribose.

Disaccharides

• They are formed by two monosaccharides.– Lactose: It´s formed by glucose and galactose. We

can find lactose in the milk.– Sucrose: It is formed by glucose and fructose. We

can find sucrose in honey. (it is the sugar we use to cook)

•

Polysaccharides• They are formed by three or more

monosaccharides.– Glycogen. It is the storage polysaccharide in animals.

Humans can use Glycogen as an energy source by hydrolysis of the polymer using specific enzymes

– Starch. It is a storage polysaccharide in plant cells, we can obtain it from potatoes.

– Cellulose. It is the constituent of the cell walls in cell plants.We can not digest cellulose, because we lack the specific enzimes that can hydrolize it.

• Monosaccharides can be directly absorbed in the intestine, they dont need digestion.

• Disaccharides and polysaccharides can´t be direclty absorbed, they must be digested until we obtain from them monosaccharides.

• If we have high levels of glucose in the blood, part of it turns into glycogen. Glycogen is accumulated in the liver and inside the muscles.

• On the opposite if there are low levels of glucose in the blood glycogen is broken into molecules of glucose.

•

Can you think examples of food rich in carbohydrates?

• Cereals, fruit, vegetables, honey, sweets, chocolate, sugar, potatoes, pasta, bread, rice.

• • If we eat a lot of carbohydrates our body turns

them into lipids (fat)• •

Lipids

• They have bigger energetic value but it is more difficult to absorb them. They can be stored in the body.

• What types of lipids are there?• Fats: Saturated and unsaturated.• Membrane lipids• Regulatory lipids

Saturated fats• They don´t have double bonds between the

carbon atoms.• Solid at environment temperature.• We find them in animal and plant food. A lot of

these fats are bad for our health, specially trans fats..

• E.g: palm oil, coconut oil. • We can find them in whole milk, butter, ham, pig

meat, chocolates, pastries and processed foods made with trans fat from partially hydrogenated oil, yolk.

Unsaturated fats

• They have double bonds between the carbon atoms.

• In vegetables and sea animals. • They are usually liquid at environment

temperature.• They are healthier than saturated fats. • E.g: Olive oil, dried fruits(avellanas,

almendras, pistachos), sunflower oil, blue fish (omega3, omega6)

Other lipids

• Cholesterol Types???• ( “bad cholesterol or LDL, good cholesterol or

HDL). Cholesterol can´t move on its own in the body. It combines with a protein, and a lipoprotein is formed.

• • Fosfolipids. They form part of the cell

membranes of the cells.•

Essential fatty acids• What are they?• Fatty acids that can´t be synthesized in the body

and must be obtained from food.• Their names?• Linoleic and linoleic acid. These basic fats are used

to build specialized fats called:– Omega-3– Omega-6

• Why are they important?– They are important in the normal functioning of all

tissues of the body.

Sources of Omega-3 and Omega-6

• Omega-3– Salmon, Trout– Seafood– Walnuts

• Omega-6– Sunflower seeds– Walnuts– Soya bean– Corn– vegetable oils (corn, safflower, soybean, cottonseed, sesame,

sunflower

Proteins• They are made of basic units called amino

acids.

• There are 20 different types of amino acids.

• There are 8 esential amino acids that our body can not synthetise and therefore we have to add them in the diet.

•

• In our diet we can have animal or plant proteins. The animal proteins have a higher nutritive value for us.

• Think examples of food rich in:• Animal proteins:– meat, fish, cheese, eggs, milk.

• Plant proteins:– leguminous plants (beans, green beans, peas),

cereals, bread.

Homework

• Look info about this minerals, function, food rich in them, and illnesses due to its lack.

• Calcium• Magnesium• Iron• Iodine

• Page 21 activities 3 and 9• Listen to cd activities 3 and 5• Page 34 activity 2. Listen to it.

Unit 2 Review

• Why do we need to eat and drink?• What type of nutrients are there?– INORGANIC AND ORGANIC

• Can you give examples of carbohydrates?• What polisacharide is known as the energy store

substance in plants?– STARCH

• What about animals? What is our main energy store polisacharide?– GLYCOGEN

• What is fibre?• Can we digest fibre? • Give examples of food rich in fibre:– Cereals, corn, wheat, rice, nuts, orange,

mushrooms

• What about proteins? What can you tell us about them?– Structure– Can we make all the amino acids?

• How much water do you drink daily?• How much should you drink?• Why is water necessary?

Tell us THINGS about VITAMINS!

• Give examples of sources of vitamins.• Can any of the vitamins be made by the

intestinal bacteria?• If you have high amounts of vitamin C, can

your body get rid of it ? How?• What about vitamin A? What is its function?• Vitamins E, K or D?• Vitamin B12?

Do we use energy when we sleep?

• We need energy to maintain the vital functions.

What is this?

Check homework

• Page 25- activity 24• Page 27- activity 26• Read page 26.

• Do for next week:• Page 27 activity 35• Make a list of items that must be included in a

food label.