Monday, December 27, 2010

Nutrition, Types of Nutrition, Balanced Diet

What is Nutrition?
Nutrition means nourishment, or aliment, is the supply of materials - food - required by organisms and cells to stay alive.
The entire process by which organism obtain energy from food for growth, maintenance and repair of damaged tissues.

Nutrient – the substances that are required for the nourishment of an organism.

Definition of Nutrition
According to the Web: Nutrition is also called nourishment or aliment. It is the provision, to cells and organisms, of the materials necessary (in the form of food) to support life. Many common health problems can be prevented or alleviated with a healthy diet.
According to the Science: Nutrition is the science or practice of consuming and utilizing foods.

Types of nutrition:-
Two main types:-
1. Autotrophic
2. Heterotrophic

1) Autotrophic Nutrition:

• A process in which organisms synthesise organic substances from inorganic
substances called Autotrophic nutrition.
Example: Photosynthesis and chemosynthesis

• Autotrophic is made up of two words Autotroph and trophos. Autotroph means auto - self, trophos means feed.Organism Which can make their own food are called autotrophic.

• The synthesis of food using light energy – photosynthesis (photo –light)

• Photoautotroph – organisms which produce organic molecules from
carbon dioxide and water using sunlight as a source of energy.
Example:green plant

2) Heterotrophic Nutrition:-

• A type of nutrition in which organism obtain energy through the intake and digestion of organic substances.

• Heterotroph is made of two words Hetero – other and trophos – feed (organism that cannot synthesis their own nutrients but obtain the nutrients from other organisms)
Example:-humans, herbivores, carnivores

Other Types of Nutrition

a) Holozioc nutrition,
b) Saprophytism nutrition
c) Parasitism nutrition

a) Holozioc Nutrition:-
- holo meanslike & zoon means animal
- The organism feeds by ingesting solid organic matter which is subsequently digested and absorbed into their bodies.
- Examples: humans, herbivores,carnivores, pitcher plants and venus plant

b) Saprophytes nutrition:-
The organism feed on dead and decaying organic matter called saprophytes.
- Digest their food externally before absorbing the nutrients into their bodies
- Examples: bacteria, fungi

c) Parasite nutrition:-
The organism obtain nutrient from living on (ectoparasites) or in (endoparasites) the body of another living organism (host) called parasite.

- They absorbs readily digested food from its host.
Examples: fleas (ectoparasites), lice, worms (endoparasites),Rafflesia

What Is The Constituents of Food Nutrition?

Nutrition is necessary for the maintenance of good health. Nutrition of the body means the supply of important nutrients in proper quantity and proportions to the body. Diet is a combination of different kinds of food. No single food can provide each and every nutrient required for the growth and the preservation of the health.

What Is The Balanced Diet?

A balanced diet must contain appropriate quantity and proportions of
Carbohydrate,protein, fat, vitamins, mineral salts and fibre.

There are mainly six costituentes of food:-

1) Proteins:- These are needed for growth and repair.
2) Fats:- These provide a source of energy and contain fat soluble vitamins.
3) Carbohydrates:- This is source of energy.
4) Vitamins:- It is required in very small quantities to keep you healthy.
5) Minerals:- It makes teeth, bones, muscles strong.
6) Water:- Water is the soul of life. Water is the carrier of other food.

1) Proteins

Proteins are complex organic compounds. The basic structure of protein is a chain of amino acids. Proteins are essential for the growth and repair if tissues of the body. They are also called as body building foods. Proteins contain Carbon, Hydrogen, Oxygen, Nitrogen and sometimes Sulphur. Proteins are very large molecules, so they cannot get directly into our blood; they must be turned into amino-acids by the digestive system. Proteins can be used as a source of energy. When excess amino-acids are removed from the body the Nitrogen is excreted as a chemical called urea. The liver makes urea and the kidney puts the urea into our urine.

Function of proteins:-

a) Proteins are the major component of muscles. It is a major part of the skin, muscles, organs, and glands. Protein is also found in all body fluids, except bile and urine. They are used in movement.

b) Proteins help your body repair cells and make new ones. Protein is also important for growth and development during childhood, adolescence, and pregnancy.

c) They serve as enzymatic catalysts, are used as transport molecules (hemoglobin transports oxygen) and storage molecules (iron is stored in the liver as a complex with the protein ferritin)

d) They mediate cell responses (rhodopsin is a protein in the eye which is used for vision)

e) Antibody proteins are needed for immune protection; control of growth and cell differentiation uses proteins (hormones).

f) People need protein for the formation of enzymes and hormones that work together in processes such as metabolism and for our sexual development.

Source of proteins:-

Milk, cheese, meat, fish, eggs, pulses, oil –seeds and nuts are sources of proteins.

Protein Deficiency Diseases

1) kwashiorkor:
A specific wasting away disease caused by protein deficiency due to malnutrition in third world countries is called kwashiorkor. This disease is found in infants who are weaned away. The weaning food is seen to lack proteins or has a poor quality of protein. Protein deficiency is a serious cause of ill health and death in developing countries. Protein deficiency plays a part in the disease kwashiorkor.

War, famine, overpopulation and other factors can increase rates of malnutrition and protein deficiency. Protein deficiency can lead to reduced intelligence or mental retardation

Symptoms of kwashiorkor:- It includes apathy, diarrhea, inactivity, failure to grow, flaky skin, fatty liver, and edema of the belly and legs.

2) Marasmus
Marasmus is another condition of a wasting away of the body tissues from the lack of protein in the diet. Protein deficiency also inhibits the growth and proper development in children.

Symptoms of Marasmus:-In marasmus the child is fretful rather than apathetic and is skinny rather than swollen with edema.

Marasmic kwashiorkor:-It has symptoms of both Marasmus as well as kwashiorkor diseases,called as marasmic kwashiorkor.

Protein deficiency also causes numerous problems like loss of weight, weakness, shrinkage of muscle tissue and edema. Other syndromes include unusually low blood pressure, unusually low heart rate, anemia and pigmentation on the skin. The metabolism rate is also likely to decrease.

2.) Fats:-

Fats contain the elements Carbon, Hydrogen and Oxygen. Fats gives heat and energy. The uses of fats add taste to the food and make the food palatable. A person who does a lot of physical work daily needs more fats.

Sources of fats :- vegetable oil, butter, ghee, olive oil ad groundnut oil.

3) Carbohydrates

Carbohydrates give energy on which all the activities of the life are dependent. They are also known as energy yielding foods. Foods rich in carbohydrates are essential for the persons who are engaged in manual work.

Sources of Carbohydrates :- Rice, wheat, maize, potatoes, barley, sugar and syrups are rich in carbohydrates.

4) Vitamins and Minerals

Foods rich in vitamins and minerals are termed as protective foods. Vitamins help in keeping our eyes, bones, teeth and gums healthy. Minerals help in the formation of blood, bones and teeth. They protect us against diseases.
Sources of vitamins and minerals:- Fruits, vegetables, milk meat, eggs, fish, liver, oil and hand polished rice.

Vitamins are divided into two categories:-

1) Fat soluble:- The fat-soluble vitamins — A, D, E, and K — dissolve in fat and can be stored in your body.

2) Water soluble:- The water-soluble vitamins — C and the B-complex vitamins (such as vitamins B6, B12, niacin, riboflavin, and folate) — need to dissolve in water before your body can absorb them.

Below is a table of the main vitamins required in a balanced diet, their source, function and typical symptoms of deficiency.

Vitamin Function Deficiency Symptoms Source
A Constituent of visual pigment. maintenance of epithelia. Poor vision. Night blindness. Dry skin. Defective epithelia lead to infections of skin, respiratory, urinary, and digestive tracts. Dairy produce. Fish liver oils. Yellow and Green vegetables.
C Maintains intercellular substances, i.e. between cells, connective tissue matrix. Scurvy, fragile capillaries, small haemorrhages under skin and gums, slow healing of wounds. Citrus fruits.
D Calcification of bone, calcium absorption. Rickets, mainly in children. Soft deformed bones, Bone demineralisation in adults. Eggs, Fish liver oils.
E Antitoxin that protects cell membranes. Possibly anaemia. Widely found. Vegetable oils, Green vegetables.
K Blood clotting. Prolonged blood clotting time. Green leafy vegetables, widely distributed in small amounts and also synthesised by intestinal bacteria.
Essential fatty acids Components of cell membranes, precursors of prostaglandins . Skin sores, renal damage, mental changes. Widely found. Required in small amounts.

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