Nutrition is important for a healthy lifestyle. In order to be
happy, we must stay healthy. Food plays an important role in our daily life.
There are many varieties in food, but eating nutritious food is the right way
to stay healthy.
Food is the
fuel of the body which is required for daily nourishment in order to maintain
the normal physiology of the body. Moreover, it gives production of heat and
energy.
Let us see the
various types of foods in brief.
1) Protein:
It is the class of food
containing nitrogen. It is derived from animal and vegetable sources and is very
important for development of human cells and is essential for growth, repair
and reproduction.There are many types of proteins like class A and class B proteins
Class A proteins are animal proteins which are as follows :
- Myosin -------- Found in meat, fish.
- Albumin -------- Found in egg, milk.
- Caseinogen ----------- Found in milk.
- Globulin --------- Found in blood globulin.
- Vitellin -------- Found in egg.
Class B are found in vegetables mainly and they lack the essential protein elements called amino acids. These are as follows:
- Gluten -------- Found in wheat, bread, cereals.
- Legumen -------- Found in peas, beans, lentils, soy bean.
- Gelatin --------- Found in animal tissues.
Proteins are composed of their tiny end product molecules called amino acids which are utilized by the body tissues. The daily requirement of protein is 80-100 gm of which 50 gm should be class A proteins.
2) Carbohydrates:
This is a combination of oxygen, carbon, hydrogen and water which supplies heat and energy. A normal adult eats about 300 gm per day as sugars and starches.
Sugars are classified as:
- Monosaccharides or single sugars ------ Ex: Glucose, Fructose.
- Disaccharides or double sugars ------- Ex: Sucrose, Maltose and Lactose.
- Polysaccharides or multiple sugars ------- Ex: Starch, Cellulose.
Starches are derived mainly from green plants, their roots, seeds, etc. as cereals (wheat, flour, rice, sago), root vegetables (potatoes); cellulose (found in stems and stalks of plants); glycogen (muscles, liver).
All complex carbohydrates are by the enzymatic actions converted into monosaccharides for proper utilization in the body.
3) Fats:
These are derived from animal and vegetable sources. They are composed of carbon, hydrogen, oxygen and stored in the body as fatty acids and glycerine.
Ex: Meat, milk, butter, cheese, egg, yolk, vegetables, fats, olive oil, etc.
These fats are used in the body for the production of heat and energy. A normal adult diet must contain 100 gm of fat.
4) Water:
It forms two third of the body weight. It is very essential for the well-being of the body and deprivation of water from the body is more serious than any other elemental deprivations. Water forms a large part of the tissues as it dissolves many substances and helps to maintain the normal salt concentration of the tissues regulating many important physiological processes of the body. Water is obtained from the liquids which an individual drinks, from fruits, vegetables and from the oxidation (i.e. metabolism) of food. The water balance of the body must be maintained so that the amount of water excreted in the urine be equal to the amount of water taken in.
5) Minerals and Salts:
These are various salts in the body required for normal physiological functions which form the mineral content of most foods.
The most important salts are as follows:
- Calcium ---- It is required by the body tissues for bone formation, teeth formation, clotting of blood and other endocrinal functions. Calcium is mostly found in milk, cheese, egg-yolk, vegetables etc.
- Sulphur ------ Essential for the overall well-being of the tissues.
- Iron ----------- It is needed for haemoglobin composition, oxygen distribution in the body and is derived from meat, eggs, cheese, bread, green vegetables.
- Sodium Chloride (common salt) ------- Helps in fluid metabolism and are available from almost all foods.
- Potassium ---------- It also helps in fluid metabolism and is available from almost all foods.
- Phosphorus ---------- It is essential for production of muscular and nervous energy, composition of hard tissues like bone, dentine. It is found in milk, egg-yolk, fish, green vegetables.
- Iodine ---------- This is an essential element required for balance and metabolic functions of the body, particularly of thyroid secretion. It is present in products of the sea salt, table salt, sweets, etc.
6) Vitamins:
These are the essential basic compounds required for life, health and growth and concerned with the well-being of the body metabolism.
The vitamins are classified as fat soluble i.e.(A,D,E,K) and water soluble (B,C,etc) respectively.
Fat soluble vitamins are available in fish, liver oils, milk, dairy products, liver, fatty fish. Hence, it is growth promoting and anti-infective in nature.
Let us discuss them in brief:
- Vitamin A ---------- It plays an important role in vision, gene transcription, immune function, embryonic development and reproduction, bone metabolism, skin and cellular health, antioxidant activity, etc. It is found in leafy vegetables, carrots, fruits, cheddar cheese, broccoli,eggs, milk, butter, liver, peas, etc and their deficiency leads to night blindness and a disease of the eye called "xeropthalmia".
- Vitamin D ---------- It plays an important role in bone health. It is found in fish liver oils, eggs, butter, fish and manufactured as natural vitamin in the skin by the exposure to sunlight and ultraviolet light. This vitamin is essential for growth of bones and teeth and promotes calcium absorption. Deficiency leads to a bony disease of the children called "rickets" and in adults called osteomalacia.
- Vitamin E ----------- It plays an important role in antioxidant function, enzymatic activities, gene expression, neurological functions, cell signaling, etc. It is found in wheat germ oil, sunflower oil, safflower oil, palm oil, avocados, mangoes, kiwi fruit, broccoli, milk, egg-yolk, green vegetables, nuts and nut oils (almond, hazlenuts,etc),etc. It's deficiency can cause myopathies, retinopathy, impairment of the immune response, ataxia, etc.
- Vitamin K ---------- It plays an important role in bone metabolism, blood coagulation, etc. It is found in leafy green vegetables, avocado, grapes, kiwifruit, meat, eggs, soy bean, pig's liver and dairy products. It is required for the formation of prothrombin. Deficiency of it causes insufficiency of blood coagulation and hence called the anti haemorraegic factor.
- Vitamin B Complex (Vit B1, B2, B3, B6, B12) ----------
vitamin B1 (Thiamine) -- Found in whole grains, pulses, pig's liver,eggs, yeast, flax and sunflower seeds, potatoes, oranges, etc.. Its deficiency causes a disease called "beri-beri".
vitamin B2 (Riboflavin) -- It plays an important role in energy metabolism. It is found in wheat germ, milk, liver, soybean, peas, lentils, popcorn, yogurt, fish, mushrooms, cottage cheese, almonds, etc. Deficiency of it causes cracks, fissures of the skin and a disease of the skin called "dermatitis".
vitamin B3 or Nicotinic acid (Niacin) -- Found in lean meat, liver, wheat germ, green vegetables. Deficiency of it causes a disease called "pellagra" and mild deficiency causes slow metabolism and decreased tolerance to cold.
vitamin B6 -- Found in meat, wholegrains, vegetables, nuts, bananas, etc. Deficiency of it causes dermatolic and neurologic changes. Deprivation of vitamin B6 results in impaired glucose tolerance.
vitamin B12 (Cobalamin) -- Plays an important role in the normal functioning of the brain and nervous system and for the formation of blood. It is found in fish, meat(liver), eggs, milk, barley grass, etc. It's deficiency causes fatigue, depression, poor memory, etc.
- Vitamin H (Biotin) -------- It is a water soluble B-complex vitamin (vitamin B7). It plays an important role in gluconeogenesis. It is found in liver, kidneys, mushroom, milk, eggs, yeast, peanuts. It is essential for the health of the skin and mucous membrane. Deficiency of it causes "dermatitis", "conjunctivitis", alopecia (hair loss) and neurological symptoms.
- Vitamin C (L-ascorbic Acid) --------- It plays a key role in wound-healing. It acts as an anti-oxidant by protecting the body against oxidative stress. It is found mostly in citrus fruits and vegetables like tomato, lemon, guava, etc. It is required for healthy development of tissues, helps to raise the immunity and protection against infection. It's deficiency causes a disease of the gums of the mouth called "scurvy".
- Vitamin P --------- It's deficiency causes bleeding under the skin.
In our daily life, we commonly do some diet mistakes and should know how to avoid them. Oranges are rich in vitamin C. We generally,
peel the orange and eat the fruit or squeeze the juice. It has a thick bitter
rind that is usually discarded. The outermost layer of the rind can be grated
and is called as orange zest. The white part of the rind, called the pericarp
or albedo and including the pith, is a source of pectin and has nearly the same
amount of vitamin C as the flesh. Orange peel has increased vitamin C and
fiber. Orange peel can be consumed only if it is grown organically (without
using any pesticides). Orange peel contains citral, an aldehyde that
antagonizes the action of vitamin A. Therefore, anyone eating orange peels
should make certain that their dietary intake of vitamin A is sufficient. Like all citrus fruits, the orange is acidic. Orange peel is used by gardeners as a slug repellent. Orange leaves can be boiled to make tea.
