B3 helps turn the food you eat into the energy you need.
Vitamin B2 deficiency is a significant risk when diet is poor, because the human body excretes the vitamin continuously, so it is not stored. A person who has a B2 deficiency normally lacks other vitamins too.
The need for vitamin B is more during illness, stress or surgery.Vitamin B is often referred to as the stress vitamin.
Smokers, drinkers or those who eat sugar in excess need more Vitamin B1 than others.