A balanced diet refers to the intake of edibles which can provide all the essential constituents necessary for growth and maintenance of the body in definite amount in which they are required by the body. A diet refers to the foods a person eats in the course of a day, or sometimes a week. The more balanced and nutritious the diet, the healthier the person can expect to be. A balanced diet means eating the right amount of foods from all food groups. While prescribing balanced diet following points must be considered.
- It must contain all the essential constituents in adequate amount.
- There must be definite proportion between the different constituents of food, the ratio between protiens, fats and carbohydrates should be 1 : 1 : 4.
- The food should be easily digestible and should be given according to agem for example starchless diet to infants.
- Cooking of food is essential because is sterilizes foodstuffs, make it palatable and easily digestible.
Constituents are substances that provide nourishment essential for the maintenance of life and for growth. Constituents are classified into the major groups which includes: Proteins, carbohydrates, fats, vitamins and minerals. These groups comprise between 45 to 40 substances that scientists have established, mostly through experiments with animals, as essential for maintaining normal growth and health. Besides water and oxygen, they include about eight amino acids from proteins, four fat-soluble and ten water soluble vitamins, about ten minerals and three electrolytes. Although carbohydrates are needed for the bodyís energy, they are not considered absolutely essential, because protein can be converted for this purpose.
Function of constituents
the primary functions of proteins include building and repairing of body tissues, regulation of body processes and formation of enzymes and hormones such as insulin that regulate communication among organ and cells, and other complex substances that govern body processes. Animal and plant proteins are not used in the forum the are ingested but are broken down by digestive enzymes called proteases into nitrogen containing amino acids. Proteases disrupt the peptide bonds by which the ingested amino acids are linked, so that they can be absorbed through the intestine into the blood and recombine into the particular tissue needed. Proteins aid in the formation of antibodies that enable the body to fight infection. Proteins serve as a major energy supplier. There are distinctive kinds of proteins, each performing a unique function in the body. Proteins form a major part of human body, next to water.
The composition of proteins in the body is like that muscle contains about 1/3 protein, bone about 1/5 part and skin consists of 1/10 portion. The rest part of proteins is in the other body tissues and fluids. Even blood contains loads of proteins. In fact the hemoglobin molecule is composed of but proteins.
Our body requires proteins for the purpose of maintenance and healthy growth. The need for consuming proteins is especially more for infants, young children, pregnant women and recovering patients. There is a constant breakdown of proteins in the body and this explains the reason why we need to consume proteins on a regular daily basis. It becomes of prime importance to ensure the daily-recommended protein intake, so as to improve health.
Sources of protein include meat, fish and eggs, as well as non-animal products, such as beans and nuts.
Inorganic mineral constituents are required in the structual composition of hard and soft body tissues, they also participate in such processes as the action of enzyme system, the contraction of muscles, nerve reactions, and the clotting of blood. These mineral nutrients, all of which must be supplied in the diet are of classes, The major elements such as calcium, phosphorous, magnisium, iron, iodine, and potassium; and traces elements such as copper, cobalt, manganese, flourine and zine.
Calcium is needed for muscle, heart and digestive system health, builds bone, supports synthesis and function of blood cells. Dietary sources of calcium include dairy products, canned fish with bones (salmon, sardines), green leafy vegetables, nuts and seeds.
Phosphorus is a component of bones and energy processing and many other functions. In biological contexts. It combines with calcium in bones and teeth. Plays an important role in energy metabolism of the cell.
Magnesium is required for processing human metabolism and for maintaining the electrical potential in nerve and muscle cells. Deficiency can result in malnourished people, especially alcoholics, leads to tremors and convulsions.
Sodium is a systemic electrolyte and present in extra cellular fluid, which it plays a role in regulating. Too much use can cause edema. Now its evident that excess use of table salt Sodium-Chloride contributes to high blood pressure.
Iron is required for many proteins and enzymes, notably for the formation of hemoglobin. Sources include red meat, leafy green vegetables, fish (tuna, salmon), eggs, dried fruits, beans, whole grains, and enriched grains.
Iodine is needed to synthesize hormone of the thyroid gland. Deficiency cause goiter. Traces elements are other inorganic substances that appear in the body in minute amounts and are essential for good health. They include copper, which is required component of many redox enzymes. Its deficiency is associated with the failure to use iron in formation of hemoglobin. Zinc form enzymes, its deficiency causes impair growth in teeth and bones. Fluorides is important for protecting against demineralization of bone. Other trace elements include chromium, molybdenum, and selenium.
Vitamins are organic compounds which enhance the metabolism of proteins, carbohydrates and fats. Without vitamins the breakdown of food could not occur. Certain vitamins participate in the formation of blood cells, hormones, nervous system chemicals and genetic materials. They are classified into two groups i.e. fat-soluble and water soluble vitamins.
Includes vitamin A, D, E and K.
They are usually absorbed with food that contains fat, further broken down by bile and the emulsified molecules pass through the lymphatic and veins to be distributed through the arteries. Excess amount is stored in the fats, liver and kidneys. As they can be stored so they donít have to be consumed everyday.
It is essential for the health of epithelial cells and for normal growth. Deficiency leads to skin changes and to night blindness or failure of dark adaptation due to the effects of deficiency on retina. It can be obtained in the diet foods of animal origin such as milk, eggs and liver. In developing countries it is obtained from carotene, which is present in the green and yellow fruits and vegetables.
Acts as a hormone and regulates calcium and phosphorous absorption and metabolism. Some vitamin D is obtained from eggs, fish, liver, butter, margarine and milk while human gets most of it from the direct sunlight. Its deficiency causes rickets in children or osteomalacia in adults.
Is essential for many vertebrate animals but its role in the human body has not been established. No clear evidence exist that it alleviates any specific disease. It is found in seed oils and wheat germ.
It is necessary for the coagulation of blood. It assists in forming enzymes prothrombin which in turn is needed to produce fibrin for blood clots. Vitamin K is produced sufficiently in the intestine by bacteria and also provided by leafy green vegetables such as Spanich and egg yolk.
Includes vitamin C and B complex.
They cannot be stored and have to be consumed on daily basis to replenish body needs. Vitamin C is important in synthesis and maintenance of connective tissues, it prevents scurvy. Main source is citrus fruits.
Vitamin B complex:
The important B-complex are thiamine (B1), riboflavin (B2), nicotinic acid or niacin, pyridoxine (B6), pantothenic acid, lecithin, choline, inositol, para-aminobenzoic acid (PABA), folic acid and cyanocobalamin (B12). These vitamins are used in variety of ranges in metabolism and prevent beriberi and pellagra. They are found in yeast and liver.
Provide a great part of energy in human diets. Edibles rich in carbohydrates are usually the most abundant and cheapest when compared with foods high in protein and fat content. They are burned during metabolism to produce energy, liberating CO2 and water.
The two kinds of carbohydrates are
Starches are found in grains, legumes and tubers whiles sugar is found in fruits and plants. Carbohydrates are used by the cells in the form of glucose. After absorption from small intestine, glucose is processed in the liver, which stores some as glycogen, a starch like substance and passes the rest into bloodstream. Glucose forms triglycerides, which are fat compounds which can be broken down into ketones. Glucose is carried by the bloodstream to the muscle and organ to be oxidized and excess quantities are stored as fats to be retrieved at times of low carbohydrate intake.
The carbohydrates containing the most nutrients are the complex carbohydrates such as unrefined grains, tubers, vegetables and fruits which also provide proteins, vitamins, minerals and fats. A less beneficial source is food made from refined sugar such as candy and soft drinks which are high in calories but low in nutrients.
They produce more than twice energy compared to carbohydrates. Fat is stored in the body for later use when carbohydrates are in short supply. Animals need stored fat to tide them over dry or cold seasons as do human during time of scarce food supply.
Fats are broken down into fatty acids that pass into the blood to form the triglycerides. The fatty acids that contain may hydrogen atoms are called saturated fatty acids and are derived mostly from animal sources. Unsaturated fatty acids are those having some of the hydrogen atoms missing. This group includes monounsaturated fatty acids, which have a single pair of hydrogen missing and polyunsaturated fatty acid, which have more than one pair missing. Polyunsaturated fats are found mostly in seed oils.
Saturated fats in bloodstream have found to raise the level of cholesterol and polyunsaturated fat tends to lower it. Saturated fats at room temperature are solid while polyunsaturated fats are liquid.
The importance of water in human life can be seen by the facts that in constitute about seventy percent of human body tissues. By weight water constitutes two third of the weight of a human body. It doesnít only maintain the temperature of body but removes waste products. In this way water is essential constituent of balanced diet.