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FOR many of us, food has been one of the most dependable pleasures in a year when so many normal activities have been put on hold. It seems particularly cruel that a common, lingering symptom of covid-19 is an altered sense of taste and smell, with studies finding that between 40 and 85 per cent of people with the illness experience some loss of these senses.

The virus that causes covid-19 attaches to ACE2 proteins in the olfactory epithelium, the tissue inside the nose where our smell receptors are located. Once the virus enters these cells, it triggers inflammation, and researchers think the inflammatory reaction causes olfactory neurons to lose their cilia, the projections on their surface that help them capture aroma molecules.

The cilia usually grow back once the infection clears up, and for most people, the loss of smell (also known as anosmia) lasts about 10 days or so. But some people don’t fully recover this ability for months, and it can have profound effects on their mental health. It is unclear why this symptom persists for so long, or whether these people will ever get their sense of smell back.

Thankfully, there is advice available for people affected by smell loss that can help them get more enjoyment from food. Anosmia is also a common side effect of cancer treatment, and , a not-for-profit cookery school, was set up to help those affected. It has now published a free cookbook, , specifically for people who have been affected by covid-19.

Drawing on by Barry Smith at the School of Advanced Study, University of London, and others, the team at Life Kitchen has learned that there are some distinctive features of anosmia and parosmia – distorted smell – related to the coronavirus. Those affected frequently find certain foods, such as meat, eggs, onions and garlic, particularly revolting.

What can they still enjoy? Most people still sense the basic tastes we detect with the tongue: sweet, sour, salty, bitter and umami. They feel the heat of chillies, coolness of mint and pungency of wasabi, sensations mediated by the trigeminal nerve. And a variety of textures in a meal can help make food more interesting.

The recipes in Taste & Flavour are designed to create pleasure from food by stimulating the still-working senses. My suggestion is peanut and sesame noodles, a dish that offers umami, salty and sour tastes, heat from chilli and soft, creamy and crunchy textures.

For other projects visit newscientist.com/maker.