B complex vitamins participate in many physiological processes and are important for maintaining the health of the human body. Vitamins B1, B2, B3, B6, B7 and B12 contribute to the normal functioning of the nervous system. B vitamins contribute to the normal function of the immune system (B6, B9 and B12), normal psychological function (B1, B3, B7, B9 and B12), contribute to the reduction of tiredness and fatigue (B2, B3, B5, B6, B9 and B12), while vitamin B5 also contributes to normal mental abilities. Vitamin B1 contributes to normal heart function, and vitamin B2 contributes to the maintenance of normal vision.