Vitamins are organic compounds that are present in food in limited quantities. They are essential for the normal functioning of the body. All vitamins, except vitamin D, have to be ingested as the human body is incapable of making them. Vitamin D is the only vitamin that can be synthesized by the body from sunlight. The human body cannot grow or function normally without the required intake of vitamins.

Types of vitamins
There are 13 types of vitamins. As they all contain carbon, they are called organic compounds. The vitamins are labeled alphabetically as vitamin A, B, C, D, E, and K. Vitamin B has subcategories called vitamins B1, B2, B3, B5, B6, B7, and B12. Vitamins are also classified based on their solubility as water-soluble and fat-soluble vitamins. Fat-soluble vitamins are stored in the fatty tissues of the body and the liver whereas water-soluble vitamins cannot be stored in the body for long and get excreted through the urine.

Vitamin A
Vitamin A is a fat-soluble vitamin that is necessary for the optimal functioning of one’s immune system. It is also needed for good eyesight. Deficiency of this vitamin causes keratomalacia and night blindness. Some dietary sources of vitamin A are sweet potatoes, carrots, kale, cod liver oil, milk, eggs, leafy vegetables, liver, pumpkin, apricot, and cantaloupe melons.

Vitamin B
All the B vitamins are water soluble and are required for the processing and conversion of food into energy. They also play a role in the maintenance of healthy hair, skin, and eyes. The insufficiency of vitamin B1 causes Wernicke-Korsakoff syndrome and beriberi, insufficiency of B2 causes ariboflavinosis and that of B3 causes diarrhea, dermatitis, and pellagra. The deficiency of B5 causes paresthesia. The insufficiency of vitamin B6 causes nervous system disorders, deficiency of B7 causes skin and digestive disorders, deficiency of B9 causes birth defects, and the deficiency of B12 causes problems with the production of red blood cells and anemia.

Some natural sources of vitamin B are yeast, whole grain products, brown rice, pork, sunflower seeds, liver, eggs, asparagus, kale, oranges, potatoes, cauliflower, bananas, cheese, almonds, yogurt, milk, persimmons, asparagus, fish, meat, green beans, avocados, tomatoes, dates, mushrooms, carrots, sweet potatoes, nuts, asparagus, and green leafy vegetables among others.

Vitamin C
Vitamin C is a water-soluble vitamin. It is also called ascorbic acid. It is found in liver, and some fruits and vegetables like broccoli, cauliflower, citrus fruits, tomatoes, bell peppers, cabbage, and spinach. Its deficiency causes improper healing, megaloblastic anemia, depression, and in rare cases, it may lead to scurvy.

Vitamin D
Vitamin D is known as ergocalciferol or cholecalciferol, but in layman’s terms, it’s called the sunshine vitamin. It is fat-soluble and usually synthesized by the body upon exposure to sunlight. It is also found in eggs, fatty fish, cod liver oil, beef liver, and mushrooms. Deficiency of this vitamin affects the immune system and also causes rickets and osteomalacia due to the impaired absorption of calcium in the body.

Vitamin E
Vitamin E is called tocopherol or tocotrienol. It is fat soluble and is found in avocados, eggs, wheat germ, whole grains, almonds, kiwi, and nuts. It is quite rare for people to have a deficiency of this vitamin, but in rare cases, it has been found to cause hemolytic anemia in newborns.

Vitamin K
Phylloquinone and menaquinones are the chemical names of vitamin K. Its deficiency can lead to bleeding disorders. This vitamin can be found in avocado, kiwi, parsley, and leafy green vegetables.