Coronavirus: Being sensitive to bitter foods could slash Covid risk, study claims


People who are super-sensitive to bitter foods could be at a lower risk of severe Covid, a study claims.

Researchers suggest that people who find the flavour of things like wine, broccoli, celery, grapefruit or Brussels sprouts overpowering might be less likely to get coronavirus.

These people are known as ‘supertasters’ and they have larger numbers of receptors in their mouth and nose that bolster natural defences against infection.

A team of doctors in Baton Rouge, Louisiana, found the supertasters were 10 times less likely to test positive for coronavirus and none of those in the study were hospitalised.

‘If you are unable to taste bitterness, you should be that much more careful,’ said one expert, Dr Alan Hirsch.

The biggest factor affecting someone’s Covid risk is their age – middle-aged or elderly people are significantly more likely to get sick – while the best way to protect yourself against serious illness is to be fit and healthy and keep long-term illnesses well controlled.

The study found that supertasters had a younger average age, suggesting that the receptors fade over time and being less able to taste bitterness aligns with old age, with both linked to a higher risk of Covid. 

Children, meanwhile, often don’t like bitter foods and have an almost zero risk from Covid. The team said more research was needed.

Nose and throat doctors in Baton Rouge, Louisiana, studied almost 2,000 people and found those who struggled to taste bitterness were four times more likely to end up in hospital with Covid (stock image)

Dr Hirsch, who was not involved with the study but is a director at the Smell and Taste Treatment and Research Foundation in Chicago, said: ‘The new findings make a lot of sense… If celery tastes bitter to you, you’re a supertaster, and if it doesn’t, be careful.’

The study was done by rhinologists – nose experts – in the US who involved 1,935 people from local doctors’ surgeries and hospitals.

They all did taste tests to work out whether they were ‘non-tasters’, who didn’t really notice bitterness; ‘supertasters’, who were very sensitive to it; or just ‘tasters’ somewhere in the middle.

WHY COULD FINDING FOODS BITTER PROTECT YOU FROM COVID? 

The reason someone’s sense of taste could be linked to their Covid risk, the Baton Rouge researchers said, lies in receptors in the mouth and throat.

Receptors named T2R38 both taste bitterness and also release nitric oxide, which can kill viruses.

Nitric oxide also stimulates the tiny hairs inside people’s airways, known as cilia, which move mucous and fragments of viruses and bacteria that get in to push them back out of the body, protecting against infection. 

People who have more of the receptors, therefore, are both extra sensitive to bitter food and extra good at naturally fighting off viruses that get into the airways, such as coronavirus. 

One of the researchers, Dr Henry Barham, told the website Wine-Searcher: ‘When these receptors activate, they do several things, including increasing the action of the cilia [small hairs that move viruses out of the airways] and increasing mucous production. 

‘They also produce nitric oxide. Nitric oxide has been shown to inhibit the spike protein of the virus that causes Covid-19.’

The study adds: ‘Differences in airway taste receptor function may reflect impaired innate immunity and a predisposition to certain respiratory tract infections and inflammatory disorders, and T2R38 functionality in the tongue correlates with nasal symptoms in healthy individuals.’

Half of people were in the middle ground, while the remaining half were split 50/50 between supertasters and non-tasters, suggesting around one in four people are one of those.

Most people won’t know which group they fall into but paper strip tests like those used in the study are available online.

As well as the taste tests, people in the study had swab and blood testing to make sure they hadn’t had Covid in the past and didn’t have it at the start of the experiment. 

After the tests everyone was followed up by researchers for three months over July, August and September 2020 to see if they caught coronavirus.

A total of 266 people tested positive for the virus and 55 of them were admitted to hospital.

Only 15 of the 266 were supertasters, while 104 were regular tasters and 147 were in the group that could not taste bitterness.

People with the weaker taste buds, therefore, were 10 times more likely to test positive, the scientists said. They also made up 47 out of the 55 hospital patients, while none of the patients were in the super-sensitive group. 

The reason that someone’s sense of taste could be linked to their Covid risk, the researchers said, lies in receptors in the mouth and throat.

Receptors named T2R38 both taste bitterness and also release nitric oxide, which can kill viruses.

Nitric oxide also stimulates the tiny hairs inside people’s airways, known as cilia, which move mucous and fragments of viruses and bacteria that get in to push them back out of the body, protecting against infection. 

People who have more of the receptors, therefore, are both extra sensitive to bitter food and extra good at naturally fighting off viruses that get into the airways, such as coronavirus.

One of the researchers, Dr Henry Barham, told the website Wine-Searcher: ‘When these receptors activate, they do several things, including increasing the action of the cilia and increasing mucous production. 

‘They also produce nitric oxide. Nitric oxide has been shown to inhibit the spike protein of the virus that causes Covid-19.’

The study adds: ‘Differences in airway taste receptor function may reflect impaired innate immunity and a predisposition to certain respiratory tract infections and inflammatory disorders, and T2R38 functionality in the tongue correlates with nasal symptoms in healthy individuals.’

The study was published in the journal JAMA Network Open by the American Medical Association.

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