Vitamin B refers to a group of water-soluble vitamins that play important roles in cell metabolism. This group includes eight different vitamins: B1 (thiamine), B2 (riboflavin), B3 (niacin), B5 (pantothenic acid), B6 (pyridoxine), B7 (biotin), B9 (folate), and B12 (cobalamin). Each of these vitamins is crucial for various bodily functions, including energy production, DNA synthesis, and repair, as well as the maintenance of healthy nerve and red blood cells.