In this video, we speak to Peter Brennan, Reader in Physiology from the University of Bristol who tells us about two possible reasons why losing our sense of smell and taste might be a symptom of COVID-19.

To contact The Physiological Society:
[email protected]

Transcript:
Recently, there have been reports of patients with COVID-19 losing their sense of taste and smell. So, what could be causing this?
Well, we don’t know exactly, but one of our Members, Peter Brennan, Reader in Physiology from the University of Bristol, tells us that there are two possible explanations:

Let’s say you have something nice cooking in the oven. As it’s baking, it releases particles that waft into your nasal cavity and attach to olfactory sensory neurons - the cells that detect what we smell and then signal this information to the brain.

COVID-19 could be killing off these olfactory sensory neurons, keeping the signal of what you’ve just smelled from getting to your brain.

Another possibility is that inflammation, part of the body’s response to fight off COVID-19, causes swelling in the nose that blocks off the airflow and prevent odour molecules from getting to the olfactory sensory neurons.

When we talk about how this relates to lack of taste, what we are really referring to is lack of flavour. Our taste buds are still sensing sweetness or saltiness but we process the complex flavours of food by combining these tastes with what we smell. This is why when we have a blocked nose and can’t smell our food, it often tastes bland!