vitamin for oxygen in blood

Vitamin B complexes are water-soluble vitamins present in many foods. Through their role as coenzymes, they enhance metabolism by converting protein and carbohydrate into energy. As well as supporting the immune system, functioning nerves, and cellular growth, they maintain the tone of the skin and muscles. It is best to supplement the B complex vitamins with a formula that contains all of them in balance, and most multivitamins made for athletes contain a large amount of the B complex vitamins.