In the elderly, oral functions are modified by changes in muscular force or saliva production among others, resulting in inadequate food fragmentation which potentially impacts on oral and gastrointestinal digestion. The purpose of this work was to evaluate the consequences of oral deficiencies on the starch and protein digestibility of bread. In vitro boluses were prepared with the AM2 masticator using normal and deficient mastication programming. Normal mastication (NM) and deficient mastication in terms of force (DfM), saliva (DsM), and their combination (DfsM) were performed. Static in vitro digestion, simulating physiological conditions in the elderly, were carried out. Bolus particle size, starch and protein digestibility, Fourier-transform infrared (FTIR) spectroscopy, and microstructure after in vitro oral and gastrointestinal digestion were analysed. More compacted boluses were observed after deficient mastication combined with greater particle sizes. The poorly fragmented boluses obtained with deficient mastication affected the oral digestion of starch, probably due to lower saliva impregnation. Digesta from deficient mastication boluses exhibited lower D-glucose release and degree of protein hydrolysis. FTIR results in the carbohydrates region also revealed weaker initiation of oral digestion of starch in DsM and DfsM boluses. These results on bread demonstrate for the first time how oral deficiencies modify nutrient bioaccessibility and, therefore, stress the importance of designing foods for specific populations such as the elderly.