Fig. 1

The potential role of the oral microbiome in obesity and metabolic disease and its effects on taste perception. The oral microbiome may contribute to the development of obesity and metabolic disease in various ways (grey box). Oral bacteria translocate to the gut (oral-gut-axis) potentially impacting well established effects of the gut microbiome on metabolic and inflammatory dysregulation in adipose tissue, systemic inflammation and eating behavior (gut-brain-axis) in obesity. Distant effects of oral bacteria on adipose tissue may also result from translocation of oral bacteria via the bloodstream (oral-blood-axis). Systemic inflammation, to which oral bacteria may contribute via the oral-blood-axis and through effects on the gut microbiome and adipose tissue, impacts taste bud renewal and in turn taste bud density, with potential consequences for taste perception. Taste perception is also affected by adipokines derived from adipose tissue. While the gut-brain-axis is well established, comparable direct effects of oral bacteria on brain function with consequences for eating behavior remain to be elucidated (blue arrow) but are largely supported by the presence of oral bacteria in the brain of patients with e.g. Alzheimer´s disease. Oral bacteria directly affect taste perception at the level of lingual taste bud cells with peripheral and central effects on food preference. Peripheral effects result from tongue coat formation, metabolite production and likely direct interactions with taste receptors, as has been demonstrated in extra-oral sites. Food choice in turn impacts the composition of the oral microbiome resulting in a vicious circus with potential consequences for weight regulation and obesity (blue box). The yellow box summarizes factors that have been identified to impact oral microbiome composition in general. Created with BioRender.com