At this point there is no European mandatory regulation as to
how far the added amount of vitamins may exceed the declared
concentration on the label. There are recommended practices on national bases like a position paper worked out by the German Food Chemical Society (LChG) regarding recommendations concerning the tolerance of nutrient declarations (LChG, 2009).
For vitamins a tolerance of ±30% for FA compared to the label declaration is generally
accepted. Due to instability of some vitamins an additional dosage of up to 50% is considered necessary and may even be exceeded in some cases, like the fortification of fruit juices.