Vitamin A nasal drops are being trialled as a possible treatment for people who have lost their sense of smell after suffering Covid.
In the 12-week Apollo trial, experts at the University of East Anglia (UEA) will explore how nasal drops could help repair tissues in the nose damaged by viruses.
The university said research from Germany had shown the potential benefit of the vitamin.
Volunteers taking part in the trial will be asked to smell odours such as rotten eggs and roses. Brain scans will then be taken to check if the treatment has repaired damaged nerves.
"We will look for changes in the size of the olfactory bulb – an area above the nose where the smell nerves join together and connect to the brain,” said lead researcher Professor Carl Philpott, from the Norwich Medical School at the UEA. “We will also look at activity in areas of the brain linked to recognising smells."
Results will be expected around 12 weeks after trials begin in December.
Loss or altered sense of smell is a common symptom of Covid-19, although many other viruses, such as flu, can also cause it.
While most people naturally regain the sense within a couple of weeks, many have been left with continuing disruption.
Prof Philpott added the UEA team hoped that the study “could one day help improve the lives of millions around the world who suffer from smell loss, by returning their fifth sense”.
Vitamin A – found naturally in many dairy foods – is already known to be beneficial for the immune system and for eyesight.
But those who use supplements should do so with caution: too much can be harmful.
