The B vitamins are a group of eight nutrients, each with unique roles in keeping the body healthy. Theyre especially important for maintaining cell health and keeping you energized. B vitamins play a vital role in maintaining good health and well-being. As the building blocks of a healthy body, B vitamins have a direct impact on your energy levels, brain function, and cell metabolism. Certain groups, such as older adults and pregnant women, are more at risk for vitamin B deficiencies