NUTRITION
BEFORE going on to discuss the subject of the digestive system it is necessary to have an understanding of the needs of the body in respect of diet.
The essentials of the diet include:— Carbohydrates. Proteins. Fats. Vitamins. Mineral salts. Water. Roughage.
If the cells of the body are to be able to function efficiently these nutritional necessities must be available in the correct proportions.
CARBOHYDRATES
Carbohydrates are to be found in sugar, jam, cereals, bread, biscuits, potatoes, fruit and vegetables. They consist of carbon, hydrogen and oxygen, the hydrogen and oxygen being in the same proportion as in water. Carbohydrates are classified according to their complexity or simplicity thus:— Polysaccharides. These are carbohydrates of the most complicated chemical structure and require a considerable amount of " break down " by digestion before they can be absorbed. Polysaccharides are starches, these include potatoes, bread, all cereals and root vegetables. Disaccharides. These are less complicated chemical compounds and do not require so much digestion before absorption can take place. Disaccharides are sugars, for example, cane sugar, beet sugar, milk sugar. Monosaccharides. These are the simplest carbohydrates, and the other two groups have to be reduced to this form before they can be absorbed from the digestive tract. Glucose is an example of a monosaccharide. Functions of Carbohydrates in the Body:— To provide energy and heat. Acts as a protein sparer. When there is an adequate supply of carbohydrate in the diet protein does not require to be used to provide energy and heat. 3. If excess carbohydrate is taken into the body it is deposited as adipose tissue in the fat depots.
PROTEINS OR NITROGENOUS FOODS
Proteins consist of carbon, hydrogen, oxygen, nitrogen, sulphur and phosphorus. During digestion proteins are broken down to their simplest form, that is, amino acids, and it is as amino acids that they are absorbed. Amino acids are divided into two categories, essential and nonessential. First class protein is the name given to protein foods which contain all the essential amino acids in the correct proportions. First class proteins are derived almost entirely from animal sources and include:— meat fish eggs chicken milk milk products game soya beans Second class proteins are so called because they do not contain all the essential amino acids in the correct proportions. They are mainly of vegetable origin, examples are, peas, beans and lentils which are known as the pulses. A small proportion of protein is to be found in other vegetables. Functions of Protein in thpBody:— To supply the essential amino acids for all cell formation in the building and repair of body tissue. To help to maintain the osmotic equilibrium between the blood and the tissue fluids. To provide energy and heat, but only when there is an insufficiency of carbohydrate in the diet.
CARBOHYDRATES
Carbohydrates are to be found in sugar, jam, cereals, bread, biscuits, potatoes, fruit and vegetables. They consist of carbon, hydrogen and oxygen, the hydrogen and oxygen being in the same proportion as in water. Carbohydrates are classified according to their complexity or simplicity thus:— Polysaccharides. These are carbohydrates of the most complicated chemical structure and require a considerable amount of " break down " by digestion before they can be absorbed. Polysaccharides are starches, these include potatoes, bread, all cereals and root vegetables. Disaccharides. These are less complicated chemical compounds and do not require so much digestion before absorption can take place. Disaccharides are sugars, for example, cane sugar, beet sugar, milk sugar. Monosaccharides. These are the simplest carbohydrates, and the other two groups have to be reduced to this form before they can be absorbed from the digestive tract. Glucose is an example of a monosaccharide. Functions of Carbohydrates in the Body:— To provide energy and heat. Acts as a protein sparer. When there is an adequate supply of carbohydrate in the diet protein does not require to be used to provide energy and heat. 3. If excess carbohydrate is taken into the body it is deposited as adipose tissue in the fat depots.
PROTEINS OR NITROGENOUS FOODS
Proteins consist of carbon, hydrogen, oxygen, nitrogen, sulphur and phosphorus. During digestion proteins are broken down to their simplest form, that is, amino acids, and it is as amino acids that they are absorbed. Amino acids are divided into two categories, essential and nonessential. First class protein is the name given to protein foods which contain all the essential amino acids in the correct proportions. First class proteins are derived almost entirely from animal sources and include:— meat fish eggs chicken milk milk products game soya beans Second class proteins are so called because they do not contain all the essential amino acids in the correct proportions. They are mainly of vegetable origin, examples are, peas, beans and lentils which are known as the pulses. A small proportion of protein is to be found in other vegetables. Functions of Protein in thpBody:— To supply the essential amino acids for all cell formation in the building and repair of body tissue. To help to maintain the osmotic equilibrium between the blood and the tissue fluids. To provide energy and heat, but only when there is an insufficiency of carbohydrate in the diet.