1. Vitamin B1 (thiamine): This vitamin helps the body convert carbohydrates into energy and plays an important role in the nervous system. B1 deficiency can lead to beriberi disease.
2. Vitamin B2 (riboflavin): It not only helps convert food into energy in the body but also plays a crucial role in skin, eye, and nerve health.
3. Vitamin B3 (niacin): This vitamin is essential for DNA formation and plays a key role in carbohydrate metabolism. High doses of niacin can be used to treat high cholesterol.
4. Vitamin B5 (pantothenic acid): Involved in the synthesis of fatty acids and hormones, as well as the formation of acetylcholine, a substance needed to transmit nerve signals.
5. Vitamin B6 (pyridoxine): This vitamin is important for nervous system development, hemoglobin formation, and immune system function.
6. Vitamin B7 (biotin): Plays a key role in maintaining healthy skin, hair, and nails. It is also involved in metabolism.
7. Vitamin B9 (folic acid): Folic acid is important during pregnancy because it helps prevent neural tube defects in the fetus. It is also essential for DNA and RNA synthesis.
8. Vitamin B12 (cobalamin): This vitamin is essential for the formation of red blood cells and a healthy nervous system. It is especially important for vegetarians and vegans because it is found primarily in animal products.

All of these B vitamins play an important role in maintaining the overall health of the body, and deficiencies can lead to a variety of diseases and symptoms. A balanced diet and supplementation can help maintain optimal levels of B vitamins in the body.