Food and Its Соnstituents. Пища и её влияние на организм человека. Учебное пособие

There are five main groups of nutrients: proteins, fats, carbohydrates, vitamins, minerals.

Macronutrients are needed by the body in relatively large amounts. They include proteins, fats, carbohydrates and the mineral elements sodium, calcium, potassium, phosphorus, and magnesium.

Micronutrients are needed by the body in smaller amounts. They include vitamins, essential fatty acids, and trace elements (the minerals iron, zinc, copper, iodine, selenium, chromium, and cobalt).

Water can also be called a nutrient, as it is vital to life.

Proteins

Our bodies are composed of millions of cells, which are constantly being replaced. As the body grows, new cells are added. Each cell contains a protoplasm, which contains (among other things) protein. Protein is vital to the growth, repair, and maintenance of the body. Protein can also be used to provide the body with energy.

Fats

They provide a concentrated source of energy, surround and protect certain vital organs, e.g. kidneys, glands, form a layer under the skin to preserve body heat and protect the skeleton and organs, provide a source of the fat-soluble vitamins A, D, E, and K.

Carbohydrates

Carbohydrates are an important source of energy and they act as a 'protein sparer', so that proteins can be used for its primary functions rather than as a source of energy. There are three main carbohydrates: monosaccharides, disaccharides and polysaccharides.

Vitamins

Vitamins are very important in nutrition even though they are required only in small amounts, but as the body cannot make most of them itself, they must be supplied by food. In general, vitamins are required to regulate the maintenance and growth of the body, and to control metabolic reactions in cells. There are two groups of them - fat-soluble and water-soluble.

Minerals

Apart from carbon, hydrogen and oxygen (the main elements that make up protein, fat, and carbohydrate), the body requires at

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least 20 other elements. They are called mineral elements and they are required for body building, control of body processes, e.g. transmission of nerve impulses. They are essential part of body liquid.

Water

Water is vital to life – 70 % of the human body is water, required for all body fluids, e.g. saliva, blood, sweat and urine, required as part of many metabolic reactions; some nutrients need to be dissolved in water for proper absorption.

IV. .

1.Name main groups of nutrients.

2.What is the difference between macro and micronutrients?

3.What are the functions of protein?

4.What are the functions of fat in the body?

5.Why does the body require carbohydrates?

6.List the functions of vitamins.

7.What are minerals required for?

8.Why is water vital to life?

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What was a main cause of death last century?

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1.It soon …………….. (to become) evident to the physiologists that foodstuffs must undergo enormous changes in the human body.

2.Ancient people …………………... (to know) how to make cheese.

3.Certainly hair, skin and muscles ………….……….. (to bear) little resemblance to the proteins of eggs, milk or wheat.

4.Cheese and milk always ………… (to be) the most important diary (&) products.

5.High blood pressure ……….... (to make) the heart work harder and …………... (to speed up) the blocking of arteries.

VI. ! .

1.Butter making originated in the countries with cold climate.

……………………………………………………………...…………

2.Freezers and microwave ovens helped to reduce the time of food preparation.

………………………………………………………………………...

3.A new method of preserving food was canning.

………………………………………………………………………...

4.The first cans were from glass.

………………………………………………………………………...

5.Liquids are very important to cooking.

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6.Fruits and vegetables keep better when cold.

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7.The engineer saw the results of the tests.

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protein ['prqutin], oxygen ['OksiGqn], carbon ['kRbqn], hydrogen

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['hidrqGqn], nitrogen ['naitrqGqn], sulphur ['sAlfq], phosphorus ['fOsfqrqs],

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complete (&') – incomplete; nature (!) – naturally III. .

TEXT B. PROTEINS

Chemistry

There are many different proteins and they are all complex molecules which contain these elements: oxygen (O), carbon (C), hydrogen (H), nitrogen (N) and sometimes sulphur (S) and phosphorus (P).

The protein molecules are made up of small units joined together in a chain. These units are called amino-acids.

At least 22 different amino-acids are known to occur naturally, and each has its own chemical name. Different proteins are made when different numbers and types of amino-acids are combined. An enormous number of different proteins can be made from 22 amino-acids. (Think how many words can be made from the 26 letters of the alphabet.)

Sources

Of these 22 amino-acids: ten are indispensable for children, eight are indispensable for adults. Proteins that contain all the indispensable amino-acids (IAAs) in sufficient quantity are said to be of high biological value (HBV), or complete proteins. HBV proteins are found mainly in animal foods: meat, cheese, fish, milk, eggs.

Proteins that lack one or more of the IAAs are said to be of low biological value (LBV), or incomplete proteins. LBV proteins are found mainly in plant foods cereals, pulses, nuts, vegetables.

There are two exceptions to this: soya beans (plant) contain HBV protein, gelatine (animal) contains LBV protein.

IV. .

1. What are the functions of protein?

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2.What chemical elements make up proteins?

3.What is an amino-acid?

4.What is an indispensable amino-acid?

5.How many indispensable amino-acids do children require, adults require?

6.What are (high) low biological value proteins and in which foods are they mainly found?

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Since the invention of freezers and microwave ovens the time spent on food preparation has reduced.

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1.Food habits ………. (to change) to fit in (") with rapidly changing lifestyle.

2.Semi-prepared foods (% "&) ………. also ………. (to contribute – ! " !) to the change in eating habits.

3.From earliest times grain …….... (to be) man’s chief means of life.

4.Since ancient times people ………………………….. (to use) salt as chemical preservative (").

5.The inclusion of fats adds flavour to cooked food. This fact

………………… (to increase) the popularity of high fat foods, which are classified as junk food.

6.For the last 100 years the situation in agriculture …………………

(to change) dramatically.

VII. ! .

1.I have known a woman once who had sixteen cows.

………………………………………………………………………

………………………………………………………………………

2.Julia felt hungry. Then she has remembered about the salad in the fridge.

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3.We’ve had enormous problems recently with ants in the kitchen.

………………………………………………………………………

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4.You haven’t yet explained clearly what you want me to cook.

………………………………………………………………………

………………………………………………………………………

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TEXT C. FATS

Chemistry

Fats are composed of carbon, oxygen and hydrogen. At least 40 different fatty acids are known. They may be either saturated or unsaturated, according to the way in which their carbon and hydrogen atoms are arranged. Fats that are solid at room temperature are mostly made up of saturated fatty acids. Unsaturated fatty acids occur mainly in oils and they are liquid.

Sources

Fats and oils are obtained from both plants and animals. Fat is present in food either as visible or invisible fat. Visible fat is easy to see in food: fat on meat, butter, margarine. Invisible fat is difficult to see: lean meat, egg yolk, fish, nuts, fruits, prepared foods, e.g. pastry, cakes, biscuits, fried foods.

Requirements

The body can adapt most fatty acids in food to suit its requirements. However, there are some fatty acids that the body needs but cannot make itself. These are called essential fatty acids (EFAs). Humans make special essential fatty acids from linolenic and linoleic acids in breast milk. This is one of the reasons why human breast milk is best for babies. Fish contain EFAs called

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omega 6 and omega 3. Omega 3 EFAs may help lower the blood cholesterol and help prevent blood clots. For this reason it is recommended that people eat two portions of oily fish per week.

IV. .

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.Name plant and animal sources of fat?

5.What is the difference between visible and invisible fat?

6.What are essential fatty acids?

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1.We ……………………… (to forget) to put food in the fridge and it ……………......... (to spoil) very rapidly.

2.Don’t eat this tart. It ……………………………………. (to spoil).

3.At the beginning of the 19th century, a Frenchmen, Nicolas Appert,

………………………………. (to discover) a method of sterilization.

4.Today scientists ………...…………...… (to improve) this process.

5.Another French scientist Louis Pasteur , later ………………….….

(to find out) that less severe heat also ……….…. (can) be effective in destroying microbes.

6.He and his colleagues ………………….. (to develop) this process.

7.Rye originally …………..…. (to appear) in the early Middle Ages.

8.A cookbook ……….… (to sell) more copies than any other books.

9.We ……………………………. (to be) at the restaurant yesterday.

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polysaccharides ["pOli'sxkqraidz], fructose['frAktqus], glucose ['glHkqus],

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