Vitamin B plays an essential role in aiding human growth and regulating important body functions, according to the American Cancer Society. Vitamin B complex is a group of 8 vitamins which includes vitamins B1, B2, B3, B5, B6, B7, B9 and B12.
According to About.com, each B vitamin performs a specific health function inside the body. Vitamin B1 contains thiamine and vitamin B2 contains riboflavin; both vitamins aid the heart, nerves and muscles. Vitamin B3 contains niacin, which is essential to keep the digestive and nervous systems functioning properly. Vitamin B5 contains pantothenic acid and stimulates growth. Vitamin B6 breaks up protein and protects the immune system. Vitamin B7 contains biotin, which aids in the production of hormones. Vitamin B9 contains folate, which is important in the creation and maintenance of cells. Vitamin B12 promotes healthy development throughout the body.
Some B vitamins are used to treat specific diseases. For example, vitamin B12 is used in the treatment of Alzheimer's disease and memory loss. It is also used for other health problems like heart disease, diabetes, sleep disorders and allergies, according to WebMD. Some people take vitamin B12 to slow the progress of degenerative diseases such as multiple sclerosis. This powerful vitamin is sometimes also used in skin care preparations to soothe skin problems such as eczema and psoriasis.