Vitamins are specific organic compounds which are naturally produced by many plants and animals. Though, our body needs Vitamins in tiny quantities but, they are considered as indispensable & very strong driving force for providing vital energy through many physiological processes. 

Our body cannot produce any vitamin itself, hence, they are obtained from external resources like sunlight & different category of  food intake. The Vitamins are classified into two categories – Fat soluble (A, D, E & K) and Water soluble (B & C) Vitamins.

Source & Functions of Vitamins:

Name of vitamin	Source	Functions
Vitamin A: (Also called Retinol)	Fat soluble –  Cheese, Egg, Milk, Carrot (Beta Carotene), Fish, Spinach, Fruits etc. Daily requirement is 600-700  µg. 1 µg = 1000mg = 40 IU	Help to improve immune system, Eye sight (specially in dim light) & keep skin & lining of Nose etc healthy. Excess intake may damage bones due to Osteoporosis.
Vitamin B: (Also called Vitamin B complex)	Water soluble_Milk, Oats, Soya, Pea, fresh fruits, Nuts, Wholegrain wheat, Fortified cereals, Avocado, Mushroom, Egg, Chicken, Mutton, Beef, Liver, Kidney, Beef etc.	B1 (Thiamin-1mg daily needed) B2 (Riboflavin_1.3mg) B3 (Niacin_15mg) Pantothenic acid & B12 (Cyanocobalamin_1.5µg) Keep Nervous system, Skin & Eye healthy & help to release energy from food B6 (Pyridoxin_1.4mg) – Helps to store energy & to form Hemoglobin B7 (Biotin) – Produced in Bowel in small quantity. It helps to make Fatty acids. B9 (Folate & Folic acid_Man-made_200µg) – Folacin forms RBCs
Vitamin C: (Ascorbic acid)	Water soluble_Citrus fruits, Strawberries, Broccoli, Sprouts, Potato etc. 40mg needed daily.	Helps to protect & keep body cells of Bone, Blood, Skin etc healthy. Helps in wound healing. Lack of this vitamin may cause Scurvy.
Vitamin D: (Ergocalciferol)	Fat soluble_Best source is Sunlight on skin. Then, Fish, Red Meat, Liver, Egg etc are also good sources. Its excess may cause Hypercalcemia and low may cause Rickets (A Bone disease). Normally, 10µg is enough per day.	Helps to maintain normal level of blood ingredients like Phosphorus, Calcium etc. It also supports the absorption of Calcium which is essentially required in development of strong Bones.
Vitamin E: (Alpha Tocopherol)	Fat soluble_Vegetable oils, Nuts, Seeds, Wheat grams etc. 3-4 mg needed daily.	It is an excellent Antioxidant, so, helps to remove free radicals from body after digestion.
Vitamin K: (Phytonadione or, Menadione)	Fat soluble_Spinach, Broccoli, Lettuce, Fats & Oils, particularly soybean and canola oil etc.	It helps in Protein synthesis & Blood clotting. Its deficiency may cause Hemophilia (Bleeding problem-blood does not clot).

Minerals are basically inorganic compounds which are required by our body in limited quantity for doing all functions like development & growth. The essential minerals including Sodium, Calcium, Potassium, Magnesium, Chloride, Fluoride, Phosphate, Sulphur, Iron, Zinc, Iodine, Copper, Manganese, Molybdenum, Selenium etc are given below, showing their functions & sources. 

The minerals also provides vital force, essentially needed to drive our body in healthy way. They are small in quantity but, their functions are very significant in many systems of body like digestive system, excretion system, reproduction system, nervous system, blood vascular system, respiratory system etc. The minerals also help in cell growth / bone growth, muscular toning etc.

Enzymes are  called the source of fermentation and they are actually protein derivatives (organic compounds), made within our body from different chain reactions of Amino acids. The enzymes are better known as Biological Catalyst because, they are used to initiate & accelerate or, increase the rate of reaction with substrate, thereby converting itself into product. 

Type of Enzymes:

1. According to location of reaction:

a. Endozymes: If enzyme and substrate reacts within cell_Oxidase, Catalase, Urease, Nitrate etc.

b. Exozymes:  If enzyme and substrate reacts outside cell_Amylase, Lipase, Casienase etc.

2. According to production of enzyme:

a. Inducible: When an enzyme is produced on need basis.

b. Constitutive: When enzyme is produced continuously.

Functions of enzymes: The enzymes perform many important tasks like: 

it provides structural strength to all cells.

It responses immediately to any chemical stimuli.

It provides defence mechanisms against many pathogens.

It helps in building muscles, destroying toxins, breaking down food particles (mainly Proteins & Carbohydrates) during digestion process. 

The above tables show six (6) categories (class of enzymes) and few examples of various enzymes in our body.

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