Выделите самое главное, говоря о функциях витаминов A, B, C.

In 1911 the young Polish scientist, Casimir Funk, published a book in which he described experiments by means of which he extracted a substance from rice hull¹ which when fed to fowl in very minute quantities cured them of the paralysis of poly-neuritis within a few hours. For this white crystalline substance he gave a name, Vitamine (“Vita” for life, “amine” the name of a certain class of chemical compounds). Though it was soon shown that the life giving material contained no amine the name remained, not only with the researchers but also with the public, and it stayed though it has dropped its “e”. Naturally the first vitamin work was biological. Many organic chemists have attempted to find the exact chemical structures of these extremely complex materials. The principal members of the vitamin groups are A, B, C, D.

For the most part we obtain our vitamins directly from foods but there are amendments to the rules.

Vitamin A can be obtained from fish livers and a variety of other foods of animal origin, or our bodies can manufacture it from carotene found in green leaves and some tubers.

The body can manufacture its own vitamin D from the ergosterol on or near skin, if exposed to sunshine. The functions of the vitamins are very varied, interesting and important.

Vitamin A. It is essential for eyes, nerves growth, reproduction and lactation and the maintenance of bodily vigor at every stage of existence. Life without vitamin A is hardly worth while. Green vegetables, milk, bitter and cod liver oil contain vitamin A.

Vitamin B. The exact amount of vitamin B for optimum human health is not known; but the minimum intake necessary to prevent beriberi or other severe nervous disturbance has been well established.

In common with most of other vitamins vitamin D is necessary for normal growth. There is probably some connection between its growth and appetite-inducing properties.

Vitamin C. The citrus fruits (oranges, lemons, grape-fruits) are sources of vitamin C. Tomatoes, raw cabbage and onions also contain vitamin C. Apples, bananas, carrots and potatoes contain some, but they are important sources only if eaten in large amounts.

If the shortage of vitamin C causes scurvy, the teeth fall out, if the shortage is less, they rot out.

Прочитайте текст и дайте характеристику витаминов группы В.

Thiamine which is designated as B₁, is one of the B vitamins that are often called the B -complex vitamins. Thiamine is destroyed by prolonged heating. The shorter the cooking time and the less the amount of water used, the less is the loss of thiamine. Important sources of thiamine are: whole grain bread and cereals, meat, milk, liver, nuts, vegetables.

Riboflavin is another of the D vitamins and was called vitamin B₂. It is essential to growth and due to it a high level of positive health is maintained. Riboflavin is little affected by heat but easily destroyed by baking soda. It is also readily destroyed by light and is soluble in water. Foods that are good sources of riboflavin are: whole grain or enriched bread and cereals, cheese, eggs, green leafy vegetables¹, meat, liver, milk.

Still another of the B vitamins is niacin. Until it was recognized as vitamin, this substance was known to chemists as nicotinic acid. Niacin is essential for growth and normal functioning of the skin and the digestive tract. Niacin is stable to air, heat and light, however, it is readily soluble in water and especially hot water. Foods that furnish niacin are: enriched or whole grain bread and cereals, meat, liver.

In many states thiamine, riboflavin, niacin, and iron are more and more commonly being added, flour, rice and other processed cereals to enrich them with these needed food constituents.

Pyridoxine, often referred to as vitamin B₆, is essential for good health. It is especially involved in certain cellular activities and in the utilization of other foods by the body. This vitamin is soluble in water and stable to heat, alkalies and acids, however, it oxidizes readily and is destroyed by light. Good food sources are heart, liver, meat, seeds and whole wheat.

Certain relationships among the vitamins make for better use of these nutrients in the body. For example, thiamine, riboflavin, and niacin are all essential in the utilization of carbohydrates. Vitamin B₆ is essential in the utilization of protein. Vitamin D is closely related to the metabolism of calcium and phosphorus and in its absence these minerals are not efficiently used in bone formation.

Many other vitamins than those presented here have been discovered, but their role in nutrition has not been determinated yet.

1 – green leafy vegetables – овощи со съедобными листьями (напр. салат)

Письменно переведите текст на русский язык.

Vitamins are organic compounds essential for the normal functioning of the body, and usually obtained from foods. Vitamins are present in minute quantities compared to the other utilizable components of the diet - proteins, fats, carbohydrates, and minerals.

Almost all knowledge of the vitamins has been obtained during the 20^th century. The discovery of the vitamins has primarily been the result of two lines of investigation: the study of nutritional disease in people and the feeding of purified diets of known composition to experimental animals. In this way vitamin deficiency diseases, known as avitaminoses, have been described.

Synthetic and natural vitamins usually have the same biological value. The use of vitamins has been the subject of different research. The principal members of the vitamin groups are A, B, C, D, E, K. The functions of the vitamins are extremely varied and important for health, development and growth.

А) о необходимости включения витаминов в питание человека,

Б) об особенностях любого из известных витаминов и его источниках,

в) перечислите по-английски: а) пищевые продукты с высоким содержанием витаминов и б) характерные особенности витаминов, представленных в тексте.

to link, link (to connect) – связывать, соединять, связь;

to lack, lack – испытывать недостаток, недостаток, дефицит;

to be deficient in – содержаться в незначительном количестве;

1. Переведите на русский язык данные словосочетания.

minute traces of copper; to perform various functions; minerals present in our food; to make up the deficiency of iron; to sprinkle fine grains of copper; to be exacting in the specification; minor constituents of plant and animal life; to оссur most frequently; by stripping cereals of all their outer coats; to make a good start; completely replaced about every six years; insufficient intake; to make adjustment; to go on excreting calcium; fully twice as great as; to turn over our body’s total supply; the greater need comes from; to be plentiful in; a striking similarity; energy-promoting or absorbing mechanism; higher animals; iron bearing hemoglobin; to be substituted for.

The minerals which we have in our system are very important links in our vital processes. The most important minerals are iron, calcium, iodine. Iron we must have in our blood to get oxygen from the air, and we must have minute traces of copper or the iron cannot be assimilated. Calcium and phosphorus must be present to make our bones and teeth, as well as to perform various other functions.

Minerals not only must be present in our food, but they must occur in a form which can be assimilated by the body. If our diet is lacking iron, you cannot make up the deficiency eating iron ore, for such a material is not assimiable. You must have copper but you cannot get it by sprinkling fine grains of copper-bearing rock on your salad. The body is not only very exacting in the specifications of what it must have, it also lays down strict rules regarding the form in which the material must be presented.

For the most part these materials are only the minor constituents of plants and animal life and, unfortunately for our good health, they occur most frequently in what we ordinarily do not like to eat. The outer layers and germ of the grains, the peelings of the tubers and fruits, the coarser, leafy, parts of vegetables. These are the materials that contain the minerals and often the vitamins. By stripping cereals of all their outer coats and refining sugar until it is whiter than the whitest snow, we have made a good start on the road to the ruination of human health, for fine milling removes 75 per cent of the minerals.

Calcium is a very important mineral in animal life. All of our calcium is completely replaced about every six years, and the only way to maintain the balance in the body is to take in a sufficient quantity in the food. If there is insufficient intake the body tries to make adjustment, but it is never completely successful. It goes on excreting calcium, taking it from bones and teeth. The calcium requirements for the growing young is fully twice as great as that of the average adult.

Phosphorus is to calcium as thunder is to lightning; the two together are required to make our bones and teeth. We must have our phosphorus and plenty of it, twice as much as calcium (about 1.4 grams per day) for we turn over our body’s total supply in less than three years. The greater need comes from the fact that phosphorus is required by some of the body proteins, phospholipins and phosphatases. Fortunately most foods are more plentiful in phosphorus than in calcium, the notable exception being milk. Meat and egg yolk are high in phosphorus.

Iron. If we had no iron, we should have no blood. There is a striking similarity in the energy-promoting or absorbing mechanism in all branches of life. Higher animals all have blood containing iron bearing hemoglobin, to act as an oxygen carrier. The green chlorophyll of plants, which promotes the reactions of photosynthesis which make all life possible, has a chemical composition quite similar to our own hemoglobin but magnesium has been substituted for iron in the molecule. Iron is found in egg yolks, in liver, meat, spinach.

1. What minerals are most important? 2. In what form must minerals be presented? 3. What are main characteristics of the given minerals?

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