NUTRITION AND FOOD
Nutrition can be defined as the sum total of all processes from which an organism derives energy to perform various activities and other materials needed for growth and maintenance of essential activities of life.
Substances that provide energy to perform various functions, repair and build up tissues and provide protection against diseases are called nutrients.
TYPES OF NUTRIENTS
Depending upon the quantity and functions, nutrients can be :
Macronutrients: The nutrients that are taken in by the body in large quantity. Carbohydrate, protein, lipids. They provide energy, heat and raw materials of the body.
Micronutrients: The nutrients which are taken in by the body in small quantity and mainly provide immunity to our body. For example, minerals and vitamins.
A Comparative account of Macronutrients
| CARBOHYDRATE | PROTEIN | LIPIDS |
| Composed of C, H, O in the ratio1:2:1 (CH2O)n | Composed of mainly C, H, O, N, S. Ph, Fe. Sometimes, Cu may be present. | Composed of C, H, O in higher proportion than carbohydrate .Phosphorus and nitrogen are also found. |
| Four types: Monosaccharides, disaccharides, oligosaccharides, polysaccharides. | Three types: Simple protein, Conjugated protein, Derived protein. | Three types: Simple, Compound and derived lipids
|
| Obtained from potato (starch),fruits like banana, cereals (rice wheat, maize, bajra)
Sugarcane, honey, milk etc. |
Obtained from pulses, meat, ground nut, egg, cheese, soya bean etc. | Ghee, butter, oil, milk, eggs and meat. |
CARBOHYDRATE : Types
| C
A R B O H Y D R A T E |
Monosaccharides– single organic compound. Eg: triose (C3H6O3), Pentose (C5H10O5) like Ribose, deoxyribose, Hexose( C6H12O6) like glucose, fructose, galactose | Disaccharides– Composed of two monosaccharides joined by condensation. Common examples are Maltose ( Glucose + Glucose)germinating seeds , Sucrose ( Glucose + Fructose) cane sugar, Lactose ( glucose + galactose) in milk.
|
Oligosaccharides yields 3 to 6 molecules of monosaccharides on hydrolysis. Eg: Maltotrisode.
Polysaccharides are formed by polymerization of a large number of monosaccharides. Eg: chitin* & cellulose( structural component), starch ( stored as food), glycogen found in liver and muscles. *Chitin consist of nitrogen. |
Functions of Carbohydrate :
- It provides energy.
- It acts as a reserve food material. Eg : starch in plant and glycogen in animals.
- It helps in protein synthesis as amino acids are formed as intermediate product of carbohydrate
- It helps in formation of anticoagulant agent Heparin; blood antigens like A, B ; Hyaluronic acid found in between the synovial joints.
- Sugars are also important component of some hormones like FSH (Follicle stimulating hormone ) and LH ( Luteinizing hormone); pentose sugar ribose and 2-deoxyribose are chief components of RNA and DNA respectively ; Galactose is the chief component of medullary sheath.
PROTEIN TYPES
| PROTEIN | Simple Protein– Composed of amino acids only. Eg: Albumin, globulin, histone etc. | Conjugatned Protein-In addition to amino acid, it contains other non protein substance (prosthetic group).They can be Lipoprotein (amino acid +lipids) eg.lipovitallin, serum; Nucleoprotein(amino acid +nucleic acid) Nucleoprotein of cytoplasm;
Glycoprotein( amino acid+ Carbohydrate) eg FSH and LH hormone, Chromoproteins( amino acid + coloured pigments)eg Haemoglobin, haemocyanin etc. Phosphoprotein( amino acids + phosphoric acid) eg. Casein of milk and ovovitalin of egg. Metalloproten( amino acid+ metal ) eg: tyrosinage, haeomoglobin. |
Derived protein – Proteins which are derived from the original protein by action of heat, enzyme or other chemical means.
Eg: Denatured proteins and peptides. Proteose. |
Function of Protein
- Proteins like ossein of bones, chondrin of cartilage, collagen of white fibres, elastin of yellow fibre act as functional and structural protein and helps in growth and repairing of tissues.
- It has several regulatory functions.
G-globulin of plasma – act as antibody
Globin- binds with haem and carries oxygen.
Actin and myosin- help in muscle contraction.
Rhodopsin ( Rod cells) and iodopsin ( Cone cells) – major pigment present in retina of eye, responsible for night and day vision respectively.
Prothombin and fibrinogen – helps in clotting of blood
LIPIDS TYPES
| LIPIDS | Simple lipids– Composed of Esters of fatty acids and various alcohols. Eg Wax( alcohol) and fat( fatty acids+ glycerol) | Compound Lipids – In addition to esters of fatty acids and alcohol, other groups are also present.
Phospholipids- (fatty acid and alcohol+phosphoric acid ) eg Sphingophospholipid, phosphatidylinositol. Glycolipids( Compounds of fatty acid + carbohydrate) eg: galactolipids Other compound of lipids include sulpholipids and amino lilipids. |
Derived Lipid – Substances derived from simple and conjugated lipids.
Eg : saturated and unsaturated fatty acids, glycerol, steroids etc. |
Function of Lipids
- It serves the purpose of fuel by providing energy.
- It serves as a reserve food as it is mainly stored in the liver.
- Certain hormones of adrenal cortex and sex hormones are formed of fat
- Fats stored under subcutaneous tissue helps to conserve the body heat
- Fats present near eye balls, kidney, ovaries helps to absorb shock and so provides protection.
| Disorder due to malnutrition
Protein and carbohydrate deficiency- Kwashiorkor Marasmus Disorder due to overnutrition Hypercholesterolemia- due to intake of excess fat Obesity-occurs due to over intake of all types of nutrients Hypervitaminosis A – excess intake of Vit A Hyperviatminosis D-Excess of Vit D causes deposition of calcium in soft tissue. Hypercalcemia – Excessive intake of calcium can causes stone in kidney. Flurorosis- Excessive intake of Fluorine causes mottled teeth and skeletal flurosis which is characterized by weak skeletal muscle. |
Essential fatty acids are those that can not be synthesized in the body and must be taken by food. These are linoleic acids, linolenic acid and arachidonic acid. *α-linolenic acid= omega -3 fatty acid, linoleic acid =omega 6 fatty acid. Non essential fatty acids are synthesized with in our body. They are Palmitic acid and stearic acid.
|
|
| ESSENTIAL AMINO ACIDS Can not be synthesized by body and should be taken with food. They are 10 in number. Arginine, Histidine, Methionine, Threonine, Tryptophan, Valine, Leucine, Isoleucine, Lysine, Phenylalanine
NON ESSENTIAL AMINO Acids can be synthesized by body and are 10 in number. Alanine , Arginine ,Asparagine , Aspartic Acid, Cysteine, Glutamic Acid , Glutamine , Glycine, Proline , Serine , Tyrosine
|
||
| Balanced diet- A balanced diet is one that gives our body all the nutrients in correct proportion. Milk is a balanced diet for children. |
MICRONUTRIENTS : Minerals These are two type – Macrominerals and Traceelements.
| Name | Source | Function | Deficiency syndrome |
| Calcium (Ca) | Milk, Cheese, cereals, green leafy vegetables | Development of bone & teeth. Blood clotting, muscle and nerve function | Muscle spasm, tooth and bone decay.
|
| Phosphorus(P) | Milk, Cheese, green leafy vegetables | Structural component of DNA, RNA and bone; Maintains normal blood pH of blood. | Demineralization of bone. |
| Sodium (Na) | Table salt | Maintains fluid balance of the body; Helps in conduction of nerve impulse | Muscle cramps |
| Potassium(K) | Most fruits, molasses, dates | Nerve excitability; muscle contraction | Rickets in children.
|
| Magnesium (Mg) | Sea food, green vegetables | Muscles and nerve relaxed | Heart and vascular irregularities |
| Sulphur (S) | Milk, eggs and meat | Essential for healthy, hair, skin and nails; helps in synthesis of Vit B1. | Inhibits healthy growth of nails and hair |
| Chlorine (Cl) | Chlorinated water and salt | Fluid acid base balance of body | |
| Copper (Cu) | Peanuts, beet, barley | Melanin, hemoglobin synthesis | Anemia |
| Cobalt (Co) | Milk and meat | Component of Vitamin B12 | Poor growth, slow sexual growth |
| Zinc(Zn) | Soyabean, coconut, almonds | Component of many enzymes; Vitamin A | Reduced enzyme formation |
| Chromium (Cr) | Tomatoes, coconut | Promotes insulin action | Diabetes mellitus |
| Manganese (Mn) | Wheat germ, legumes | Functions of mammary gland, normal reproduction | Infertility, menstrual problem, |
| Iron (Fe) | Liver, eggs, green leafy vegetables | Components of respiratory pigments, respiratory enzymes | Anemia |
| Molybdenum (Mo) | Black gram , cabbage, potatoes, bajra | Synthesis of hemoglobin, and absorption of iron | Disturbances in iron metabolism |
| Selenium (Se) | Wheat germ, garlic, mango | Acts as antioxidant | Premature aging and cataract formation |
| Fluorine (Fl) | Fish, tea, water | Prevent dental caries | Tooth decay |
| Iodine (I) | Iodized salt | Component of thyroid hormone | Goiter |
VITAMINS
Vitamins are organic compounds that are essential for normal growth, body activity and in prevention of certain diseases. Vitamins act with the enzyme and catalyse many important metabolic reactions of the body. Thus vitamins are also called as ‘biological catalyst’.
Fat Soluble
| Name | Chemical name | Source | Deficiency desease |
| Vitamin A | Caretenoid, retinol | Fish, liver, egg, yellow and green fruits, tomatoes etc | Xerophthalmia-
Night blindness |
| Vitamin D | Vit D2– Calciferol
Vit D3– Cholecalciferol |
Fish liver oil, egg yolk, | Poor development of bone, ricket in children, Osteomalacia. |
| Vitamin E | Tocopherol | Wheat germ oil, leafy vegetables, butter milk | Sterility in experimental male rats. |
| Vitamin K | Vit K1– Phylloquinine
Vit K2– farnoquinine |
Green vegetables, soyabean oil | Haemorrhages
|
Water Soluble
| Name | Chemical name | Source | Deficiency symptoms |
| Vitamin B1 | Thiamine | Sea food, yeast, cereals, | Beriberi, loss of hair |
| Vitamin B2 | Riboflavin | Liver, cheese, | Intolerance to light, premature aging |
| Vitamin B3 | Niacin | Liver | Pellagra |
| Vitamin B5 | Pantheonic acid | Liver | Paresthecia |
| Vitamin B6 | Pyriodoxine | Rice bran | Anemia, peripheral neuropathy |
| Vitamin B7 | Biotin | Liver | Dermatitis |
| Vitamin B9 | Folic acid | Liver, green leaves | Deficiency during pregnancy is associated with birth defects |
| Vitamin B12 | Cyanacobalamine | Liver, eggs, | Megaloblastic anaemia |
| Vitamin C | Ascorbic acid | Lemon, orange | Scurvey |
Water
Water forms about 70% – 90% part of protoplasm and 45 -80% part of the whole body.
- Water is the most suitable solvent for many organic and inorganic compounds like electrolytes, enzymes, hormones and acts as a good dispersion medium for the materials of the protoplasm.
- It acts as an important medium of transport of essential substances in the cytoplasm.
- It regulates temperature of the body.
- It provides the medium for rapid diffusion of molecules.
- It helps in formation of biological membranes.
Roughage
Undigested fibrous part of the food is called roughage. It helps food to move down the alimentary canal by peristaltic movement. Absence of roughage may create a condition of constipation.
QUIZ
Try our quiz in the website.