Vitamins are essential for the growth and development of the human body. Vitamins are found in natural foods. A good diet virtually ensures an abundant supply of vitamins. Sometimes due to certain medical conditions, the body is deprived of certain vitamins, leading to a deficiency.

Vitamin A deficiency is a common disease in poorer parts of the world and causes night blindness. Vitamin A is found in fish, liver and green vegetables. Failure to consume sufficient quantities of meat, milk or milk products leads to a deficiency in Vitamin B12. This deficiency causes megaloblastic anemia and, if severe enough, can result in irreversible damage to the nerves, liver and intestinal tract. A person can experience hallucinations, memory loss, eye disorders and anemia.

Vitamin C, found in green vegetables, berries and citrus fruits, helps prevent infection, enhances immunology and can help prevent cancer. A lack of Vitamin C can cause anemia, bleeding gums, muscle degeneration and blood clots. A deficiency in Vitamin D affects the bones, heart, kidneys and the thyroid gland. Common symptoms are irregular heartbeat, Osteoporosis and brittle and fragile bones. Vitamin D also enhances the immune system.

Vitamin E is found in vegetable oils, whole grains, spinach and milk. A deficiency may cause an enlargement of the prostate gland, gastrointestinal disease, impotency and decreased circulation. Vitamin E helps prevent cancer and cardiovascular diseases. Vitamin K plays an important role in the formation of bones and blood clotting. It also converts glucose into glycogen for storage in the liver. A lack of Vitamin K leads to a low platelet count and poor blood clotting.

Folic acid is essential for the formation of red blood cells and is vital for normal growth and development. Folic acid is found in beans, beef, barley and chicken, amongst others. A deficiency of folic acid causes depression, anxiety and birth defects in pregnant women.

Vitamin deficiency can treated by recommending dietary regulations, oral supplements, or by injections. Oral supplements are useful for those unable to consume food rich in vitamins. Injections are useful for persons with diseases that prevent absorption of fat-soluble vitamins.