Increasing evidence suggests that the diminution of cereals consumption and the increase of more refined products consumption are associated with the apparition of marginal deficiencies in micronutrients such as thiamin. The phosphorylated form of thiamin (TDP) is an important co-enzyme involved in several metabolic reactions, and the consequences of thiamin deficiency (TD) depend on its severity. For example, TD leads to alteration in brain metabolism with a decrease in brain concentrations of TDP, a reduction in activities of TDP-dependent enzymes, an increase of lactate concentration, a reduced tissue pH and a selective loss of neurons. An optimised thiamin supply could also prevent the formation of radical species, protect against metabolic stress and prevent the formation of Advanced Glycation End Products. These observations emphasise the importance of whole cereals, and particularly whole bread, in the prevention of thiamin deficiency. In this view, to get whole bread with maximal nutritional density, several steps of the transformation of grain into bread should be further examined: selection of cultivars with a high thiamin level, use of less refined flours and optimisation of the fermentation process during bread making.