Text № 1 «digestion»

Very little natural food can serve as nourishment just as it is, glucose is about the only natural substance that can. While chemists were trying to find what foods are made of, physiologists were trying to learn just what food must be used as nourishment.

It soon became evident to the physiologists that foodstuffs must undergo enormous changes in the human body, because the body tissues are profoundly different from the foodstuffs that nourish them. There is very little carbohydrate in the animal body and human fat is not much like either the vegetable fats or milk fat. Certainly the hair, skin and muscles bear little resemblance to the proteins of eggs, milk or wheat.

The word “food” is used loosely to designate anything edible whether it is a natural product such as wheat, fish, or potatoes, a partially processed product such as flour; or cooked foods such as an apple-pie. If it is edible it is food regardless of what must be done to it before it is eaten. Because of this uncertainty of meaning, the nutritionists use the word “food-stuffs” for those portions of the foods the body can use, mainly the carbohydrates, fats and proteins.

All digestion is a reaction of the foodstuffs with water or what the chemist calls a hydrolysis. As the digested food passes along the intestines¹ it consists of 3 sugars, mostly glucose, about 20 amino acids, glycerol and several fatty acids. There are also salts and some other substances that were in the food, such as acids, chlorophyll, cholesterol and vitamins. Such is the food as it passes through the intenstinal wall into the blood stream to be distributed to the various tissues for growth, repair, or the production of energy.

1- пищеварительный тракт

Text № 2 «carbohydrates in our lives»

Carbohydrates commonly occur as starch and sugar. The chief function of starches and sugars in our lives is to produce energy. If we eat them and then if we don’t utilize their potential energy they are stored usually as fat. If ordinary sugar molecules are eaten they are split in two to give the simple sugars, glucose and fructose. Starches end up as glucose.

In the body metabolism, fats and carbohydrates play more or less interchangeable roles, but it is generally considered that health is best served if 40% to 50% of the total energy value of the food is in the form of carbohydrates, and 30% to 35% in the form of fats.

Text № 3 «fat in the diet»

Every physiological process in the body requires energy. Energy is needed for the organism to function, to grow and to engage in physical activity, and is stored in food in the form of proteins, fats and carbohydrates.

Fat contains twice as much energy as protein or carbohydrate, and is therefore an important source of energy. It also contains the essential polyunsaturated¹ fatty acids and is a vehicle² for the fat-soluble vitamins A.D.E and K. Apart from its nutritional aspects, fat also gives food taste and consistency, and is an excellent vehicle for flavourings.

In the body fat provides support and protection for internal organs and provides an important reserve of energy.

The body makes its own fatty acids, but only those that are saturated and mono-unsaturated. The essential polyunsaturated fatty acids can be produced only by plants and so have to be supplied via foods.

1 – to saturate – насыщать

2 – vehicle – связующее вещество