Nutrition may be defined as the science of food and its relationship to health. Nutrition also called nourishment or aliment is the provision, to cells and organisms, of the materials necessary (in the form of food) to support life. It is concerned primarily with the part Played by nutrients in body‘s growth, development and maintenance. The chemical components of food, which perform these functions, are called nutrients and the study various nutrients, their functions, food sources and their utilization by the human body their effect on human wellbeing is called nutrition. A food is any substance, liquid or solid, which provides the body with:
- Heat and energy
- Growth and repair
- Regularize the body processes
Types of Nutrients
The word protein is derived from the Greek word ’Proteins’, which means “principal" or “Prime". Proteins are the principal components of all living cells and are important practically in all aspect of cell structure and functions.
Proteins are composed of carbon, hydrogen (Water and Oxygen), nitrogen and sulphur in varying amounts. Proteins are built from 23 or more amino acids present in plant and animal proteins, and they function to build, repair and maintain body tissues with numerous chemical reactions in our body.
Function of Protein
Protein is composed of different amino - acids needed to build, repair and maintain body tissues. It has other functions as well, such as making antibodies fight infection, building enzymes, hormones and red blood cells that assist with numerous chemical reactions in our body.
There are two sources of protein
- Animal protein: Meats, fish, poultry, milk, cheese, and eggs are some of the best protein sources which contain all essential amino - acids.
- Vegetable protein: Vegetable protein is found mainly in the seeds of vegetables such as pulses, grains, nuts, and cereals. The proportion of protein in green and root vegetable, e.g. peas, beans such vegetable protein contain more amino - acids.
Carbohydrates are energy sources for our body muscles, brain, and nervous system. Carbohydrates that are not used immediately by the body for energy is stored as fat. On the other hand, if our body does not get enough carbohydrate to supply its energy needs, it will bum dietary or body fat and protein for energy. This robs our body of protein that it needs for report end maintenance.
There are three main sources of carbohydrates:
- Glucose: Found in the blood of the animal and in fruits and honey.
- Fructose: Found in fruit, honey, and cane sugar.
- Sucrose: Found in beet and cane sugar.
- Lactose: Found in milk.
- Whole grains: Rice, barley, rye, and oat.
- Powdered grains: Flour, cornflower, and arrowroot.
- Vegetable: Potato, turnips, peas and beans.
- Cereals: Cornflakes and shredded wheat.
- Cooked starch: Cake and biscuits.
- Pasta: Spaghetti, macaroni, and noodles.
- Fruits: Banana, apple, and pears.
Cellulose is the coarser structure of vegetable and cereals, which is not digested but is used as roughage in the intestine to aid digestion. It is often referred to as dietary fiber.
Minerals are inorganic elements that are absorbed by the body and they are indispensable to our health.
There are 19 mineral elements, most of which are required by the body in very small quantities. Some of these have important physiological or biochemical roles to play.
The functions and sources of minerals:
- Calcium: Helps to make strong bones and teeth.
Sources: Milk products, leafy vegetable, fish bones, cereals, and millets.
- Magnesium: It helps bones and muscles to use certain vitamins.
Sources: Nuts and seeds, dark green leafy vegetable and whole grain products.
- Iron: Carries oxygen to the blood.
Sources: Meat, offal, egg yolks, wholemeal flour, green vegetables and fish.
- Phosphorus: Work with calcium in making bones and teeth.
Sources: Liver, kidney, eggs, cheese, bread, and fishes.
- Iodine Helps to make hormone produced by the thyroid gland.
Sources: Seafood, iodized salt and vegetables from the sea.
- Sodium / potassium: Keep the water balance in cells.
Sources: Fruits and vegetables, milk product and salt added meat and fish.
Fat is an essential part of our body. Fat is a substance which contains carbon, oxygen, hydrogen in form of fatty acids. Fat is not water soluble but solidifies if keep at room temperature or below. Fat is the sources of energy and is of 2 types. They are solid fat and oil fat. Healthy fats are good for health.
Functions of Fats
- Provide heat and energy.
- Protect vital organs.
- Aids in absorption of fat.
- Essay the flavour of food and help to maintain the body temperature.
- Animal fat: Butter, suet, lard, cheese, bacon, meat, fat oily fish etc.
- Vegetable fat: Margarine, cooking fat, nuts, soybean etc.
Cooking of fat
The nutritive value of fat is not affected by cooking. During cooking process, a certain amount of it may be lost from food when the fat melts. Cooking fat makes it more digestible.
Vitamins are organic substances that our body needs but cannot make inadequate amount. Vitamins must be obtained from food or nutritional supplements. Some of the essential functions that vitamins fulfil are. To help convert the fats and carbohydrates in food into body energy, assist in the formation of bone and tissues and promote tissue growth and repair.
The 13 vitamins our body needs are either fat - soluble or water - soluble. Fat - soluble vitamins are A, D, E, & K. They cannot be stored for future use by the body. Water -soluble vitamins are B complex and C. They cannot be stored and should be obtained daily.
- Assists in children's growth
- Helps the body to resist infection
- Good vision, strong bones, healthy skin and help to heal wounds.
- Animal food: Halibut, liver oil, cod - liver oil, kidney, butter, cheese, eggs, milk, and herrings.
- Plant food: Carrots, spinach, tomatoes, pumpkin, papaya, mango and apricots.
Keep the nervous system in good condition. Enable the body to obtain energy from carbohydrates. Encourage the growth of the body.
Some foods containing Vitamin 'B'
- Thiamine (B1): Yeast, bacon, peas, oatmeal, wholemeal, bread, almonds, groundnuts, etc.
- Riboflavin (B2): Egg, cheese, liver, meat extract, yeast, milk, etc.
- Nicotinic acid: Beef, kidney, liver, brewer's yeast, meat extract, poultry, fish, groundnut, etc.
- Pyridoxine: (B6): Liver, meat, dairy products, egg, fruits, cereals, etc.
- Pyridoxine (B12): Liver, kidney, meat, fish, egg, milk and cheese, and vitamin B12 are not found in food of vegetable origin.
Vitamin 'C' (Ascorbic acid)
Vitamin 'C' is necessary for the growth of children. Assists in the healing of cuts and uniting broken bones. Prevents gum and mouth infection.
Ascorbic acid is found in grapefruit, lemon, orange, banana. Blackcurrants, strawberry, tomatoes, cabbage, spinach, guava, radish, and cauliflower.
Vitamin 'D’ controls the use of the body to make calcium. It is, therefore, necessary for healthy bones and teeth.
Sources:Action of sunlight on the deeper layers of the skin (75%) and other are fish - liver oil, oily fish, egg yolk, dairy products, etc.
Preserves cells and tissues, and make healthier skin and hair.
Source:Found in a variety of foods, e g. vegetable oil, whole grain etc.
It helps in clotting blood
Sources:Dark green leafy vegetables.
Oli, Gopal Singh and B. B. Chhetri.Hotel management. Kathmandu: Buddha publications Pvt. Ltd., 2015. Book.
Shrestha, Dinesh; K.C, Saroj; karki, karuna; Sharma, Robin; elt.Hotel Management. kathmandu: Arcadia Publishing House Pvt. Ltd., 2068,Shrawan.
- The chemical components of food, which perform vital body functions, are called nutrition.
- Nutrition can be defined as the science of food and its relationship to health.
- Nutrition essential to our body are: carbohydrate, protein, fats, vitamins, minerals, water.
- Proteins are composed of carbon, hydrogen (Water and Oxygen), nitrogen and sulphur in varying amounts.
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