The need for norms in the supply of (micro) nutriments has gradually become apparent, alongside anxiety from a growing number of users (consumers, manufacturers, scientists and politicians) about the excess consumption of certains nutriments, consumer concern about food, and competition between industrialists and between countries. These norms have taken the form of a series of benchmark values, particularly with regard to vitamins, going from a lower limit defining the dangers of deficiencies up to the safe limit and maximum intake defining the dangers (or absence thereof) of excess, with recommended daily intake per person in between (a list of French recommended daily intakes was published in 2000). The latter take account of scientific data on the prevention of major pathologies and may therefore be regarded as optimum. Despite efforts to bring these recommendations into line, particularly through Coder Alimentarius and the EU, with a view to greater trading and health efficiency, they may vary from one country to another. This is because the policies on recommended daily intake in a particular country are the result of a variety of factors: experts' opinions, the validity of scientific knowledge, pressure from industrialists, changing fashions, +/- "natural" tastes and behaviour on the part of consumers, level of concern about public health and the nutritional level of the population as a whole. In order to correct any anomalies in the supply of vitamins to their populations, the various countries use, depending on the situation, the following methods: making the addition of vitamins to certain foods obligatory (margarine, cereals), allowing their addition to other foods by manufacturers (see feature), putting them back into other foods (milk), awareness campaigns..., but always within a legal framework.