The Role of Smell in Taste Perception
Smell (olfaction) contributes approximately 75-95% to what we perceive as "taste," with the actual taste sensation from the tongue accounting for only a small fraction of flavor perception. 1
Understanding the Distinction Between Taste and Flavor
The question conflates two distinct sensory systems that work together to create what most people call "taste":
True taste sensation involves only the five basic tastes detected by taste buds on the tongue: sweet, salty, sour, bitter, and umami 1
Flavor perception is the integrated sensory experience combining true taste (5-25%) with retronasal olfaction (75-95%), plus contributions from texture, temperature, and trigeminal sensations 1, 2
The Dominant Role of Olfaction
In sensory science studies evaluating food products, flavor/aroma attributes appear in 95% of temporal sensory evaluations, while basic taste attributes appear in 95% as well, but the flavor/aroma component dominates the overall perception. 1
When patients lose their sense of smell:
Only 53% of patients with hyposmia or anosmia can correctly identify sour, bitter, and salty tastes, compared to 100% of patients with normal smell function 3
Patients with smell disturbances significantly more often have abnormalities in taste perception than patients with normal olfaction, even though their taste buds remain functionally intact 3
The loss of "taste" that patients report is actually loss of flavor perception due to loss of retronasal olfaction, rather than loss of the sense of taste per se 1, 4
Clinical Evidence from COVID-19 Studies
The COVID-19 pandemic provided extensive real-world evidence of this relationship:
Patients with COVID-19-related olfactory dysfunction consistently report concurrent "taste" loss, but psychophysical testing reveals that 75.9% have objective olfactory dysfunction while only 43.1% have true gustatory dysfunction 5
There is marked inconsistency between subjective reporting of taste loss and objective psychophysical test assessment, with patients overreporting taste dysfunction when their primary deficit is olfactory 5
Taste dysfunction in COVID-19 is often reduced less than smell dysfunction, with 78.8% recovering taste by 30 days versus 74.1% recovering smell 6
Common Clinical Pitfalls
Patients typically cannot accurately assess whether their complaint involves true taste loss versus flavor loss from olfactory dysfunction 7, 8
Approximately 76.5% of patients with objective smell disturbances subjectively estimate their sense of taste as normal, demonstrating poor insight into the source of their deficit 3
The distinction matters clinically because treatment approaches differ: olfactory training is the primary intervention for smell loss, while true taste disorders require different management 4, 7
Practical Implications
When a patient complains of "taste" loss, objective psychophysical testing using validated instruments (UPSIT for smell, Burghart Taste Strips for taste) is mandatory to differentiate between conductive olfactory loss, sensorineural olfactory loss, and true gustatory dysfunction. 1, 7, 5
The sensory science literature demonstrates that in food evaluation studies, flavor/aroma modalities are evaluated in 95% of studies alongside taste (95%), texture (40%), and mouthfeel (50%), reflecting the integrated nature of eating experience 1