Vitamins do not directly serve as a source of energy, but they aid the enzymes that generate energy from the energy producing nutrients like protein, carbohydrates and fats. Thus, they play an important role in helping out in the chemical reaction that leads to fruitful generation of energy, which enables you to perform your daily routine activities effectively. Adequate vitamin intake promotes health fitness, by strengthening the bones and teeth. It makes your immune system strong, thereby enabling you to overcome various kinds of infections. For example, vitamin B3 works in combination with coenzyme Q10 and contributes a great deal in boosting your energy levels. Vitamin B6 plays a vital role in human metabolism. Vitamin B12 acts as an active participant in the biochemical reactions that lead to the production of energy. Infact, it is for this reason that vitamin B12 is sometimes also referred as energy vitamin. Vitamin C is requisite for the synthesis of a small molecule named carnitine that helps in transporting fat to the cellular organelles called mitochondria, for its conversion into energy.