The term vitamin was derived from “vitamine”, a compound word coined in 1912 by the Polish biochemist Casimir Funk when working at the Lister Institute of Preventive Medicine. 

The name is from vital and amine, meaning amine of life, because it was suggested in 1912 that the organic micronutrient food factors that prevent beriberi and perhaps other similar dietary-deficiency diseases might be chemical amines. 

This was true of thiamine, but after it was found that other such micronutrients were not amines the word was shortened to vitamin in English.

Vitamins are organic compound (contains carbon) and essential nutrient the body cannot produce enough of and which it needs to get from food

There are currently 13 recognized vitamins.

Year of discovery	Vitamin	Food source
1913	Vitamin A (Retinol)	Cod liver oil
1910	Vitamin B1 (Thiamine)	Rice bran
1920	Vitamin C (Ascorbic acid)	Citrus, most fresh foods
1920	Vitamin D (Calciferol)	Cod liver oil
1920	Vitamin B2 (Riboflavin)	Meat, dairy products, eggs
1922	Vitamin E (Tocopherol)	Wheat germ oil, unrefined vegetable oils
1929	Vitamin K1 (Phylloquinone)	Leaf vegetables
1931	Vitamin B5 (Pantothenic acid)	Meat, whole grains, in many foods
1931	Vitamin B7 (Biotin)	Meat, dairy products, Eggs
1934	Vitamin B6 (Pyridoxine)	Meat, dairy products
1936	Vitamin B3 (Niacin)	Meat, grains
1941	Vitamin B9 (Folic acid)	Leaf vegetables
1948	Vitamin B12 (Cobalamins)	Meat, organs (Liver), Eggs

Vitamins are either fat-soluble or water-soluble.

Fat-soluble vitamins:
Fat-soluble vitamins are stored in the fatty tissues of the body and the liver. Fat-soluble vitamins are easier to store than water-soluble ones and can stay in the body as reserves for days, some of them for months. Fat-soluble vitamins are absorbed through the intestinal tract with the help of fats (lipids). Vitamins A, D, E, and K are fat-soluble.

Water-soluble vitamins:

Water-soluble vitamins do not get stored in the body for long – they soon get excreted in urine. Because of this, water-soluble vitamins need to be replaced more often than fat-soluble ones. Vitamins C and all the B vitamins are water soluble.

List of Vitamins
1. Vitamin A (Retinol, Retinal)
2. Vitamin B1 (Thiamine)
3. Vitamin B2 (Riboflavin)
4. Vitamin B3 (Niacin, Niacinamide)
5. Vitamin B5 (Pantothenic acid)
6. Vitamin B6 (Pyridoxine, Pyridoxamine, Pyridoxal)
7. Vitamin B7 (Biotin)
8. Vitamin B9 (Folic acid, Folinic acid)
9. Vitamin B12 (Cyanocobalamin, Hydroxocobalamin, Methylcobalamin)
10. Vitamin C (Ascorbic acid) 11. Vitamin D (Ergocalciferol, Cholecalciferol)
12. Vitamin E (Tocopherols, Tocotrienols) 13. Vitamin K (Phylloquinone, Menaquinones).                     

                                       “Deficiency”

Vitamin A 
Night blindness and eye disease, dry pimply skin, increased infections, kidney stone, depression, irritability, attention deficit Severe deficiency leads to edema, paralysis, and heart failure.

Vitamin B1
Weight Loss, Weakness, Irregular Heart Rate, Emotional Disturbances, Wernicke Encephalopathy, Beriberi, depression, irritability, attention deficit Severe deficiency leads to edema, paralysis, and heart failure.

Vitamin B2
Weakness, throat swelling/soreness, swollen tongue, skin cracking (including cracked corners of the mouth), Dermatitis, Anemia, Blurred vision and itching, watering, sore, or bloodshot eyes, Eyes becoming light-sensitive and easily fatigued.

Vitamin B3
Indigestion, fatigue, canker sores, vomiting, depression, Severe deficiency, called pellagra, can cause symptoms related to the skin, digestive system, and nervous system.

Vitamin B5
Fatigue, depression, irritability, insomnia, stomach pains, vomiting,Burning feet, upper respiratory infections, muscle cramps, numbness in toes, sleeplessness etc.

Vitamin B6
Deficiency of vitamin B6 leads to Neurological symptoms like depression, irritability, nervousness, mental confusion, convulsions and peripheral neuropathy glossitis, depression, hallucinations, muscle pains.

Vitamin B7
Deficiency of vitamin B7 leads to Anemia, loss of appetite, nausea, dermatitis Glossitis, depression, hallucinations, muscle pains.

Vitamin B9
Deficiency of vitamin B9 leads to Poor growth, Tongue inflammation, Gingivitis Loss of appetite, Shortness of breath, Diarrhea, Irritability, Forgetfulness, Mental sluggishness.

Vitamin B12
Deficiency of vitamin B12 leads to strange sensations, numbness or tingling in the hands, legs or feet, difficulty walking (staggering, balance problems), anemia, a swollen, inflamed tongue,yellowed skin (jaundice),

Vitamin C
Symptoms of vitamin C deficiency includes: Dry skin, Splitting hair, Swelling and discoloration of your gums, Sudden and unexpected bleeding from your gums, Nosebleeds, Poor healing of wounds, Problems fighting infections.

Vitamin D
Deficiency of vitamin D leads Rheumatoid arthritis, Prostate cancer, Heart disease Rickets in childrens, Osteomalacia in adults.

Vitamin E
Low levels of vitamin E can cause many digestive system problems, which will lead to poor absorption of nutrients from the digestive tract.This leads to diseases in pancreas, liver, gall bladder, Nervous system, Dry hair or loss of hair.

Vitamin K
Deficiency of Vitamin K leads heavy menstrual bleeding, gum bleeding, nose bleeding,Hardening of the arteries or calcium-related problems are the other common signs of vitamin K deficiency.