B vitamins (Niacin, pantothenic acid, b2, b6, b12 and biotin), vitamin c and iron are important for energy metabolism and the reduction of tiredness and fatigue pantothenic acid is important for mental performance, while iron, iodine and zinc are important for normal cognitive function copper, zinc, iron, selenium, vitamins a, c, b6, b12 and d are important for the normal function of the immune system vitamins b2, c, and e as well as manganese, selenium, copper and zinc help to protect cells from oxidative damage zinc, biotin and copper contribute to the maintenance of normal hair and skin selenium is important for the maintenance of normal nails vitamin c contributes to collagen formation for the normal function of skin, teeth and gums