UNIT 3 FOOD AND NUTRITION

WHAT TO LEARN:1. NUTRITION AND FEEDING

2. FOOD AND NUTRIENTS: sugar or carbohydrates, lipids, proteins, vitamins, mineral salts and water.

3. THE NUTRITIONAL NEEDS: energetic, structural, functional and regulatory.

4. DIET (definition). Balanced diet.

5. MEDITERRANEAN DIET

6. SPECIAL DIETS.

7. FOOD PRESERVATION

8. METHODS OF PRESERVING FOOD.

1. NUTRITION AND FEEDING1. NUTRITION AND FEEDING

• NUTRITION:

It is the set of processes which permit organisms to use and transform the nutrients in order to keep alive.

Nutrients:chemical substance obtained from food after digestion that are needed for the three vital functions.

• FEEDING:

It is the process by which we obtain the nutrients we need from the environment.

2. FOOD AND NUTRIENTS2. FOOD AND NUTRIENTS

Food provide us with the nutrients we need for carrying out our vital functions.

These biomolecules are: sugar or carbohydrates, lipids, proteins, vitamins, mineral salts and water

• 2.1-CARBOHYDRATES (glucids)2.1-CARBOHYDRATES (glucids) They are energy giving substances

We find them in bread, cereals, vegetables, pasta and potatoes.

There are two groups:2. 1.1 Simple carbohydrates or sugars: sweet, crystalline and

soluble in water.a) Monosaccharides: One single molecule

ex: Glucose and fructoseb) Disaccharides: two monosaccharides joined together.

ex: sucrose and lactose

2.1.2 Complex carbohydrates: Polysaccharides. Formed by many monosaccharides joined together. No sweet, no

crystalline and no soluble in water.Ex:- starch (almidón): many glucoses together. It stores

glucose in plants - Cellulose, which makes fibre: it is not used for energy by

humans

2. 2 Lipids2. 2 Lipids::• There are a variety of different substances which are

insoluble in water.• There are three groups:

Fats: they are high-energy-giving molecules. They can be saturated fats (from animals)

unsaturated fats (from vegetables)

Membrane lipids: they make up cell membranes.

Regulatory lipids: hormones, some vitamins.

2. 3 Proteins:2. 3 Proteins:• They are the most important structural molecules.• They are made up of smaller molecules called amino

acids, joining together.

• There are 20 different amino acids.

12 are non essential, they can be produced by our organism

8 are essential, they have to be taken from the food. They are mainly in animals products such as fish, meat, eggs and milk.

2.4- Vitamins-It is an organic compound required as a nutrient in tiny amounts by the organism.

-They can be destroyed easily by heat, light or oxygen so that we must eat fresh food.

-Classification: (types of vitamins according to solubility) fat soluble (hydrophobic). They are four A, E, K and D. They can be stored in the liver water soluble (hydrophillic). They are 9 (8B and C). They can not be stored.

2.5 Mineral salts: They are inorganic compounds. They carry out different functions: - Structural function (bones and teeth) - Regulatory function (nervous and muscle system) - Metabolic function.They are present in food (fruit, vegetables) and water2.6 Water: It is the most important molecule in living things (It is 63%

of our body´s mass). It is the universal solvent where biochemical reactions

are carried out. Water is a transport system of substances and it

regulates the body´s temperature.

3.1-Energetic needs

Our body needs energy to carry out vital functions. We obtain this energy through energetic nutrients : sugar, fats and sometimes proteins. Respiration is a set of chemical reactions that releases energy from energetic nutrients (in mitochondria).Basal metabolism, it is the energy that a person spends when he is resting. It is the minimum amount of energy necessary to carry out vital function (breathing, heart beating…)Every person has got a basal metabolism rate (BMR). People with high BMR can eat large amount of food without putting on weight because they “burn “a lot of energy. People with low BMR put weight easily. BMR depends on body mass, height, age and sex.

3. NUTRITIONAL NEEDS3. NUTRITIONAL NEEDS : energetic, structural, functional and regulatory. : :

The food we eat satisfies 3 kind of needs:

BMR can be calculated approximately like this:

• It is expressed in kilocalories (Kcal) per day. It is

dependent on body mass, size, age and sex.

3.2-Structural needsWe need structural nutrients in order to build and

repair biological tissues.

The most important structural nutrients are proteins but also lipids and mineral salts.

• 3.3-Functional and regulatory needsVitamins and mineral salts are responsible for the

correct functioning of our body.

4. DIET4. DIET4.1 Definition:

The amount and kind of food taken by a person everyday.

4.2 Balanced diet: it is a diet that provides energetic, structural and functional nutrients in an adequate proportion.

Characteristics:• It must be varied. We must take between 10-15% of proteins;

55-60% of sugars and 30% of fats.• We must eat several times a day (between 4-5)• We must eat fresh vegetables and fruit to obtain vitamins.• We must avoid TV dinner( ready meal) because they have loosen

most of the nutrients.• We must include unsaturated fats and reduce the saturated fats

and cholesterol in our diet.• We must eat food rich in alimentary fibre (25 g/day)

5. MEDITERRANEAN DIET

• It refers to the traditional food from countries in southern Europe. It is considered one of the most balanced and healthiest diets.

The principal aspects of it are:• High olive oil consumption.• High consumption of legumes, cereals, fruits and vegetables.• Moderate consumption of dairy products (containing or made of

milk).

• Moderate to high fish consumption.

• Low consumption of meat.

Advantages:Very attractive because of its varietyPrevents heart diseasePrevents constipation, colon cancer and obesity

6. SPECIAL DIETS ( Sometimes people follow special diets to correct or prevent

different kinds or nutritional illnesses caused by inadequate food (incorrect nutrition) or insufficient food (malnutrition).)

• Hypocaloric diets: they include a lower energetic foods average, so that they are used for loosing weight.

• Hypercaloric diets: the opposite diet, it is used to put on weight.• Low cholesterol diets: it is used when you have a high blood

cholesterol level, so that you have to eat less high fat food and replace it with olive oil and blue fish.

• Rich in fibre diets: they include high amount of fibre and they are adequated for constipation (estreñimiento).

• Low fibre diets: eating a low fibre diet can be helpful when you have diarrhea or other digestive problems.

• (Without lactose, without gluten, glucose controlled diet…)

7. FOOD PRESERVATION

It is a process to preserve food to make it last longer. It tries to stop food decomposing.

Decomposition is caused by:• The action of enzymes• The multiplication of microorganisms.

8. METHODS OF PRESERVING FOOD: (to avoid microorganisms growth)

• Cold: reduces microorganisms speed of reproduction: refrigeration, freezing and deep freezing

• Heat: kills microorganism:

Sterilization: Tª= 1100 C- 1200 C

Pasteurisation 72 0 C during 15 seconds, rapid cooling down

UHT: few seconds at 1350 C• Use of preservatives (conservantes):

- Large amount of sugar and salt: it produce a loss of water inside the microorganisms

- Vinegar and spices: they stop the microorganisms spreading.• Drying by eliminating the water in foods• Irradiation by radiation that destroys microorganisms• Smoking by smoke that reduces the amount of water in foods.

How much sugar has a Coke?• http://www.youtube.com/watch?v=yKZ2ZqBYlrI&feature=fvwrel

https://www.youtube.com/watch?v=rhkWQnHpaIk

What happens if you boil Coca Cola?

https://www.youtube.com/watch?v=OBzvN9FLx4Q

Nutrient Use in the body Good sources

Carbohydrate To provide energyCereals, bread, pasta, rice and potatoes

Protein For growth and repairFish, meat, eggs, beans, pulses ,dairy products

Lipids (fats and oils)

To provide energy. Also to store energy in the body and insulate it against the cold. Butter, oil and nuts

MineralsNeeded in small amounts to maintain health

Salt, milk (for calcium) and liver (for iron)

VitaminsNeeded in small amounts to maintain health Fruit, vegetables, dairy foods

Alimentary fibreTo provide fibre to help to keep the food moving through the gut Vegetables, bran

Water Needed for cells and body fluids Water, fruit juice, milk