Text15 a. Fat-Soluble Vitamins

Vitamin A. The chemical name of vitamin A is retinol. It can be found only in animal foods, but milk and some vegetable foods also contain the deep yellow or orange carotenes which can be converted in the body to retinol. Vitamin A is not widely distributed in food. It is generally considered that the richest natural sources of retinol are fish liver oils. Also it is found in animal liver, kidney, dairy products and eggs. Lard and dripping, however, contain none. This vitamin is necessary for vision. In children in many parts of the world deficiency results in severe eye diseases. Vitamin A is also necessary for the maintenance of healthy skin. But one should remember that excessive doses of vitamin A (for example from taking large amounts for long periods) can be poisonous.

Vitamin E also belongs to fat-soluble ones. И occurs widely in foods, especially in those eaten by the poorest of the world's people. Because it is stored in the body, deficiency is likely only in infants who have very low fat stores.; It is stated that the richest sources of vitamin E are vegetable oils, cereal products and eggs. Animal fats and meat, fruit, and vegetables also have it but not so much. One should know that if there is little vitamin E in the body, an anaemia may develop. Excessive intakes are not toxic.

Vitamin К is widespread in most vegetable foods such as spinach, cabbage, cauliflower, peas and beans. It is essential for the normal clotting of blood.

Text 15 B

Vitamin D is associated with fatty foods. It is wry necessary for maintaining the level of calcium and phosphorus in the blood. It achieves this by enhancing the absorption of dietary calcium from the intestine, and by helping to regulate the exchange of calcium between the blood and bone.

Infants and children who have too little vitamin D develop rickets, with deformed bones which are too weak to support their weight. These changes readily become permanent, so it is important to prevent their development. So people who absorb too little calcium and vitamin D from the diet may suffer from bone softening. Too high an intake of vitamin D causes more calcium to be absorbed than it is needed ї and it damages the kidneys. That is why it is necessary for the vitamin D intakes to be carefully controlled.

Unit 16

Запам'ятайте вимову поданих нижче слів:

thiamin тіамін, вітамін В₁

riboflavin рибофлавін, вітамін В₂

nіасіn нікотинова кислота, ніацин

folic acid фолієва кислота

pyridoxine піридоксин, вітамін В₆

biotin біотин

pantothenic acid пантотенова кислота

complex а складний, складений; и комплекс

lead v (led; led) вести, приводити (до чого-небудь)

offal и потрух; покидьки; тельбухи;

offal milk молоко низької якості

pork свинина;

pork chop свиняча відбивна

yeast n дріжджі; закваска

raw а 1. сирий, неварений; недоварений, недосмажений;

raw material сировина;

raw sugar нерафінований цукор

leaf n (pi leaves) лист;

leafy а листяний

leafy vegetables листяні овочі, зелень

yolk n жовток (яйця)

obtain отримувати, здобувати

metabolism n метаболізм, обмін речовин

Text 16 A Water-Soluble Vitamins

Vitamins В and С are considered to be-water-soluble. The vitamin В is complex and includes thiamin (vitamin B₁), riboflavin (vitamin B₂), niacin (nicotinic acid), folic acid, vitamin B₆ (pyridoxine), vitamin B₁₂, biotin, pantothenic acid. The chemical structure of each of the B-vitamins is different, but they have some common features. As a rule they act as "co-factors" in different enzyme systems in the body-, they are found in the same foods; and being water-soluble, they are not stored for long in the body. These characteristics mean that diets containing too little of the B-vitamins can lead to multiple deficiency within a few months.

Thiamin (B₁) and pantothenic acid are necessary for the release of energy from carbohydrate (thiamin) and fat (pantothenic acid). They are wide-spread in both animal and vegetable foods. Rich sources of thiamin are those containing more than 0.04 mg per 100 kcal, such as milk, offal, pork, eggs, vegetables and fruit. It should be noted that cooking may result in considerable losses from these foods.

Riboflavin [B₂] and niacin are necessary for the utilization of energy from food. Riboflavin is a bright yellow substance, which is widely distributed in foods. The main sources of this vitamin are milk, meat and eggs. The main sources of-niacin in the average diet are meat and meat products, potatoes, bread and cereals. Milk and eggs are not rich in this vitamin.

Folic acid (folate) has several functions, including its action with vitamin B₁₂ in rapidly dividing cells. Deficiency of this vitamin leads to anaemia and the degeneration of nerve cells. Vitamin B₁₂ does not occur in vegetable foods, but only in animal products and in microorganisms including yeast. Liver is the richest source of vitamin В₁₂, but useful amounts of it also occur in eggs, cheese, milk, meat and fish. As for folic acid, raw green leafy vegetables are rich in it, but most fruits, meat and dairy products contain little. Folic acid is easily destroyed in cooking, much being lost in the water used for cooking vegetables.

Vitamin B6 is necessary for the formation of haemoglobin. Its deficiency is rare in man, but high Intakes are dangerous. In the diet vitamin B6 can be found in milk, meat, potatoes and other vegetables.

Biotin is essential for the metabolism of fat. Very small amounts of it are needed. Egg yolk is a rich source of biotin. Smaller amounts are obtained from milk and dairy products, cereals, fish, fruit and vegetables.

Text 16 B. Vitamin С

Vitamin С (or ascorbic acid) is needed for the maintenance of healthy connective tissue. Man cannot form his own vitamin C, and must therefore obtain it from food. Bui this vitamin is not wide-spread in foods. There are small amounts of it in milk and liver. In most diets all the vitamin is taken from vegetables and fruit: potatoes, fruit juice, citrus fruit and green vegetables. The amount of vitamin С in vegetables and fruit depends on season and their freshness.

Vitamin С is easily lost during the storage; preparation and cooking of vegetables and fruit. When the plants are growing in the spring and early summer, they have higher quantities of vitamin С. It may be preserved by freezing.

As we know, milk also has small amounts of vitamin C, but it is easily lost when milk stands on the window or и doorstep quite long. This may be important for little children and those old people for whom milk may be one of the few sources of this vitamin. The only vegetable materials which have no vitamin С are cereals and dried peas.