Table 1.

Mechanisms potentially implicated in presbygeusia

Factor	Implicated mechanism	Reference
Reduced fungiform papillae density	Reduced taste acuity perception	Fischer et al., 2013 [38] Pavlidis et al., 2013 [35] Piochi et al., 2018 [36] Piochi et al., 2019 [37] Walliczek-Dworschak et al., 2017 [35]
Reduced vascularization of the tip of the tongue and changes in shape of fungiform papillae	Reduced taste acuity perception	Pavlidis et al., 2013 [26]
Alteration of taste bud homeostasis; decreased number of taste buds, taste cells and taste progenitors/proliferating stem cells	Decline in taste sensitivity	Feng et al., 2014 [34]
Single nucleotide polymorphisms (SNPs) in the genes that code for the ENaC β subunit (SCNN1B gene) and the TRPV1 nonspecific cation channel (TRPV1 gene)	Modification in individual’s suprathreshold salt taste perception	Pavlidis et al., 2013 [26]
Decrease salivary flow rate and change in salivary composition	Reduced/altered taste perception	Walliczek-Dworschak et al., 2019 [35] Mese and Matsuo, 2007 [39]
Reduced salivary mucin glycosylation and binding capacity to oral epithelial cells	Impaired saliva viscoelasticity and decreased activation of bitter taste receptors	Pushpass et al., 2019 [40]
Specific alterations in brain areas and different neural signatures in the central nervous system	Reduced taste acuity perception	Iannilli et al., 2017 [41] Green et al., 2013 [42]
Reduced masticatory performance and number of missing teeth	Inability to fully chew food	Alia et al., 2021 [12]
Presence of dental prosthesis	Reduced ability to grind food and reduced rate of salivary secretion	Wayler et al., 1990 [43] Alia et al., 2021 [12]
Alterations in olfactory functions (drying of the olfactory mucosa, damage to the olfactory epithelium due to environmental factors, abnormal turnover with reduction in the number of olfactory receptor cells)	Abnormal retro-nasal stimulation of the olfactory receptors during deglutition with mitigation of the taste experience	Doty, 2018 [44]
Impairment in the oral microbioma	Impaired oral health Physical barrier exerted by surface tongue film of oral bacteria limiting access of tastants to taste receptors. Production of metabolites by oral bacteria Modification in saliva flow and pH	Belibasakis, 2018 [45] Schamarek et al., 2023 [46]