Тексты про витамины на английском

The word “vitamin” goes back to the Polish scientist Casimir Funk in 1912.  He was studying a substance in the layer that covers rice.  This substance was believed to cure a disease called beriberi.

Funk believed the substance belonged to a group of chemicals known as amines.  He added the Latin word «vita,» meaning life.  So he called the substance a “vitamine” — an amine necessary for life.

Scientists have discovered fourteen kinds of vitamins.  They are known as vitamins A, the B group, C, D, E and K.  Scientists say vitamins help to carry out chemical changes in cells.  If we do not get enough of the vitamins we need in our food, we may develop a number of diseases. 

This brings us back to Casmir Funk.  His studies of rice were part of a long search for foods that could cure disease.

One of the first people involved in that search was James Lind of Scotland.  In the 1740s, Lind was a doctor for the British navy.  He investigated a problem that had existed in the navy for many years. 

The problem was the disease scurvy.  So many sailors had scurvy that the navy’s lost some of its strength.  The sailors were weak from bleeding inside their bodies.  Even the smallest wound would not heal.  Doctor Lind thought the sailors were getting sick because they failed to eat some kinds of foods when they were at sea for many months.

Doctor Lind separated twelve sailors who had scurvy into two groups.  He gave each group different foods to eat.  One group got oranges and lemons.  The other did not.  The men who ate the fruit began to improve within seven days.  The other men got weaker.  Doctor Lind was correct.  Eating citrus fruits prevents scurvy.

Types of Vitamins

Vitamin A helps prevent skin and other tissues from becoming dry.  It is also needed to make a light-sensitive substance in the eyes.  People who do not get enough vitamin A cannot see well in darkness.  Their eys may get dry.  This can result in infections and lead to blindness.

Vitamin A is found in fish liver oil.  It also is in the yellow part of eggs.  Sweet potatoes, carrots and other darkly colored fruits and vegetables contain substances that the body can change into vitamin A. 

Vitamin B-one is also called thiamine.  Thiamine changes starchy foods into energy.  It also helps the heart and nervous system work well.  Without it, we would be weak and would not grow.  We also might develop beriberi. Apart from rice thiamine is found in beans , peas, nuts, meat and fish.

Another B-vitamin is niacin.  It helps cells use food energy.  It also prevents pellagra -a disease that causes weakness, reddish skin and stomach problems.  Niacin is found in meat, fish and green vegetables.

Vitamin B-12 helps produce red blood cells.  It is found naturally in foods such as eggs, meat, fish and milk products.  It also helps babies of pregnant mothers before they are born .  Vitamin B-12 is found in green leafy vegetables and other foods and citrus fruits.  In some countries, it is added to products like bread.

Vitamin C is needed for strong bones and teeth, and for healthy blood.  It also helps wounds heal quickly.  Because our body stores little vitamin C we must get it every day in foods such as citrus fruits, tomatoes and cabbage.

Vitamin D helps make calcium in the blood.  Calcium is needed for nerve and muscle cells to work normally.  It also is needed to build strong bones.  Ultraviolet light from the sun changes a substance in the skin into vitamin D.  Fish liver oil also contains vitamin D.  In some countries, milk producers add vitamin D to milk so children will get enough.

Vitamin K is needed for healthy blood.  It thickens the blood around a cut to stop bleeding.  Bacteria in the intestines normally produce vitamin K.  It can also be found in pork products, liver and in vegetables like cabbage, and spinach.

Some people fear they do not get enough vitamins from the foods they eat.  So they take products with large amounts of vitamins.  They think these products or vitamin supplements will improve their health and protect them from disease.

Experts note that taking too much of some vitamins can be harmful.  People should be sure to discuss what vitamins they take with their doctors.  This is because some vitamins can cause harmful effects when mixed with medicines.

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Vitamins are a group of organic substances required in our diets in small amounts for growth and nutrition. They are usually found in foodstuffs or taken as supplements. Yet vitamins probably present a wider gap between myth and reality in the layman’s understanding than almost any other area of our diet. Most people have a recognition that Vitamin C prevents scurvy, that Vitamin A is found in fish-liver oils, or that Vitamin D is found in dairy products; many people believe that Vitamin E preserves youth and prevents sterility, or that Vitamin C can present colds and cancer. Beyond this, however, there is still considerable ignorance and widespread myth. The reality behind the common practice of taking vitamin supplements is less dramatic, although vitamins do represent an important component of the necessary human diet.

The word vitamin was formed from the Latin word «vita» («life») and the Greek word «amine» because 19th-century scientists believed that they were formed only from amino acids. Amino acids are the twenty essential code elements which arrange themselves in varied sequences or chains to form complex proteins, the basic foodstuff of life. These organic acids (containing the essential ingredient NH2), in conjunction with the nucleic acids (DNA material being composed of the four bases adenine, guanine thymine, and cytosine), «translate» the genetic instructions from the DNA of the chromosome to the RNA transcript, and in turn transfer these instructions from the transcript to proteins.

If proteins are the building blocks of life, then amino acids are the building blocks of proteins. Plant cells form amino acids from the compounds which the plant draws up from the ground, such as the nitrates and ammonia salts. Animals, however, cannot perform this conversion of simple inorganic substances to amino acids, so they must ingest them in the form of food — with herbivorous animals consuming plant proteins in vegetables and carnivorous animals consuming animal proteins in the bodies of their prey.

Vitamins are essential aids in many body processes, converting food the energy, building and maintaining cells, and other functions.

Vitamins can thus be looked at as a crucial ingredient in the long-term maintenance of health. Vitamins come in two main forms — water soluble and fat soluble. The fat-soluble vitamins, including A, D, E, and K, «are absorbed by the body with the aid of fat and then stored in body fat». Because they are stored in this way, we do not need to take these vitamins daily, and it is usually possible to maintain adequate amounts in the body through a normal, well-balanced diet. But for the same reason, it is possible to overdose on these vitamins by taking too many as supplements, in which case they can build up to toxic levels and actually cause harm to the person taking them.

The water-soluble vitamins, including Vitamin C and all of the B complex vitamins, are «used up quickly or excreted in urine and perspiration; they are not stored and should be consumed daily. They break down quickly and can be partially lost through premature harvesting, long and improper storage, processing, overcooking, and cooking in the water». The high amounts of both water-soluble and fat-soluble vitamins found in raw vegetables and fruits are often lost when they are processed, with a few exceptions such as carrots, which actually gain in vitamin A by being cooked.

The best sources of the different vitamin groups are now well-known. Vitamin A, including retinol and «provitamin carotenoids,» is found in liver, butter, whole milk, cheese and egg yolks (retinol) and in carrots, leafy greens, sweet potatoes, pumpkins, cantaloupes, and so on (provitamin carotenoids). Vitamin A is extremely important information and maintenance of skin and mucous membranes, in visual functions, and in bone and tooth development. A deficiency of Vitamin A can cause impaired growth, night-blindness, diarrhea, and increased mortality in the worst cases. Experiments in giving large Vitamin A supplements for malnourished children have had mixed results; some reported a reduction in infant and child mortality, but a recent study of Sudanese children between 9 and 72 months found little difference in a test group that was given mega doses of A (200,000 units), and a placebo group that was given only small amounts of Vitamin E.

Vitamin D (calciferol), found mostly in fortified dairy products but also in fish oils an egg yolks, is particularly important for hardening of bones and teeth and aiding in the intestine’s absorption of calcium. Deficiencies of D can cause rickets in children and more rarely, osteomalacia in adults; overdoses are known to cause retarded growth, kidney damage and calcium deposits in the soft tissues. Vitamin E (Tocopherol), is found in vegetable oil, green leafy vegetables, wheat germ, egg yolk, butter, and liver. It functions as an «antioxidant» for other vitamins, preventing C and A and other fatty-acid proteins from being burnt up prematurely; in this way, it helps prevent cell-membrane damage. Most experts believe that Vitamin E deficiency can only occur in extreme cases of malnutrition, but this doesn’t mean that supplements might not be useful. One recent study found that Vitamin E‑rich blood helped to prevent angina (cardiovascular distress), for reasons not yet understood.

The B vitamin group is very important. B1 or thiamin, found in meats, whole grains, and nuts, serves in carbohydrate metabolism and production of ribose for RNA and DNA. B2 or Riboflavin, in the liver, milk, cheese, meat, and fortified grains, functions as a coenzyme to help cells use oxygen to get energy from food. B6 or pyroxidine, found in meats, shellfish, whole grains, and vegetables, also serves as a coenzyme in protein metabolism. B12, found in the same foods and in milk products, serves as a coenzyme in nucleic acid synthesis and development of red blood cells. Deficiencies of the B group can cause anemia, skin problems, and other diseases.

Other vitamins include niacin, folacin (folic acid), biotin, and pantothenic acid, all of which serve as coenzymes to help synthesize fat, form vital chemicals in the life processes, or assist in energy metabolism for the body processes. Some typical symptoms of deficiency are fatigue, depression, or anemia. Recently, it has been found that Vitamin K, a fat-soluble substance, is essential in the blood-clotting process, and it is hoped that it can be applied to the treatment of hemophilia, wound or surgery recovery, and other medical problems.

As a group, vitamins are often confused with the many hundreds of minerals (inorganic substances) that are also needed for basic growth and maintenance functions of the body. Like vitamins, most minerals can also be found in foods, but shortages of minerals are also possible. There have also been unproven claims for vitamins in general, such as that supplements increase children’s IQ. Probably the greatest confusion exists about Vitamin C (ascorbic acid), a substance found in many vegetables and fruits, and needed for holding body cells together, healing wounds and broken bones, and resisting infection. Many extravagant claims, such as curing cancer and preventing common colds, have been made for Vitamin C. While some evidence exists of side-benefits, long-term studies have failed to give conclusive evidence that C can produce miracles. Like other water-soluble vitamins, however, C is easily depleted from the body, and any diet without sufficient C from fresh fruits and vegetables will need supplements.

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