Vitamins

A vitamin is an organic compound required as a vital nutrient in tiny amounts by an organism.

The discovery dates of the different types of vitamins and their sources
 

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, eggs
1922	Vitamin E (Tocopherol)	Wheat germ oil, unrefined vegetable oils
1926	Vitamin B12 (Cobalamins)	liver, eggs, animal products
1929	Vitamin K1 (Phylloquinone)	Leafy green 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, eggs, grains
1941	Vitamin B9 (Folic acid)	Leafy green vegetables

  
List of vitamins; Recommended Dosage, Deficiency Diseases, Upper Intake Limit, Disease due to overdose and source of vitamins 
Each vitamin is typically used in multiple reactions, and, therefore, most have multiple functions.

Vitamin generic descriptor name	Recommended dietary allowances (male, age 19–70)	Deficiency disease	Upper Intake Level (UL/day)	Overdose disease	Good sources
Vitamin A	900 µg	Night-blindness, Hyperkeratosis, and Keratomalacia	3,000 µg	Hypervitaminosis A	Orange, ripe yellow fruits, leafy vegetables, carrots, pumpkin, squash, spinach, liver
Vitamin B1	1.2 mg	Beriberi, Wernicke-Korsakoff syndrome	N/D	Drowsiness or muscle relaxation with large doses.	Pork, oatmeal, brown rice, vegetables, potatoes, liver, eggs
Vitamin B2	1.3 mg	Ariboflavinosis	N/D		Dairy products, bananas, popcorn, green beans, asparagus
Vitamin B3	16.0 mg	Pellagra	35.0 mg	Liver damage (doses > 2g/day) and other problems	Meat, fish, eggs, many vegetables, mushrooms, tree nuts
Vitamin B5	5.0 mg	Paresthesia	N/D	Diarrhea; possibly nausea and heartburn.	Meat, broccoli, avocados
Vitamin B6	1.3–1.7 mg	Anemia, peripheral neuropathy	100 mg	Impairment of proprioception, nerve damage (doses > 100 mg/day)	Meat, vegetables, tree nuts, bananas
Vitamin B7	30.0 µg	Dermatitis, enteritis	N/D		Raw egg yolk, liver, peanuts, certain vegetables
Vitamin B9	400 µg	Megaloblast and Deficiency during pregnancy is associated with birth defects, such as neura tube defects	1,000 µg	May mask symptoms of vitamin B12 deficiency; other effects.	Leafy vegetables, pasta, bread, cereal, liver
Vitamin B12	2.4 µg	Megaloblastic anemia	N/D	Acne-like rash [causality is not conclusively established	Meat and other animal products
Vitamin C	90.0 mg	Scurvy	2,000 mg	Vitamin C megadosage	Many fruits and vegetables, liver
Vitamin D	5.0 µg–10 µg	Rickets and Osteomalacia	50 µg	Hypervitaminosis D	Fish, eggs, liver, mushrooms
Vitamin E	15.0 mg	Deficiency is very rare; mild hemolytic anemia in newborn infants.	1,000 mg	Increased congestive heart failure seen in one large randomized study.	Many fruits and vegetables
Vitamin K	120 µg	Bleeding diathesis	N/D	Increases coagulation in patients taking warfarin	Leafy green vegetables such as spinach, egg yolks, liver