Taste, as detected by the tongue, registers sweet, salty, bitter, sour, and umami elements of foods. Different parts of the tongue are responsible for picking up different elements. In many cases of anosmia, the ability to taste remains. This can lead to craving for sweet or salty foods as people seek out the experience of tasting.
Smell is the process by which we experience and interpret odour molecules. This happens in the brain from signals transmitted by the olfactory epithelium. Odour molecules reach the olfactory epithelium by two pathways: through the nose, and also through the back of the throat when we eat.
Smell and taste combined is what we perceive to be flavour.
Our sense of touch also comes into play as we enjoy food. We think of touch as through the finger-tips, but the sensation of touch in our mouth is an important part of the eating experience. Crunchy, chewy, soft and melty - the perception of texture is integral to enjoyment. Soft potato crisps, anyone?
And finally, the trigeminal nerve completes the picture. This is the largest of the cranial nerves and links eyes, nose and mouth to transmit sensory information to the brain, but also signals that activate muscles and glands. The trigeminal nerve detects the temperature of food, reacts to stimulants like eye-watering, nose-clearing wasabi or notes the cool tingle of peppermint.
Tests to measure what senses are functional and what may be reduced or missing are only really available in research settings at the moment. You have to be your own Sensory Detective and investigate what's happening in your mouth. Next time you eat, think about which senses are doing their job and focus on what you can experience rather than what you can’t.
Thanks to Barry Smith and Alexander Fjaeldstad who are leading research in the perception of our senses. You can watch the whole webinar here on the AbScent YouTube channel.