Drink coffee and eat vegetables to ward off the coronavirus, study suggests

Healhty vegan breakfast bowl. Avocado, egg, tomato, feta cheese, arugula and bread and cup of coffee. Top view
Drinking coffee with a vegetable-rich salad may help to ward off the coronavirus. (Stock, Getty Images)

Drinking coffee and upping your vegetable intake may ward off the coronavirus, research suggests.

Lockdown restrictions have ended in England, however, the pandemic is far from over.

The UK's unprecedented vaccination programme means deaths remain relatively low, with 96 fatalities within 28 days of a positive test recorded on 20 July. The coronavirus is continuing to circulate, however, with 46,558 confirmed cases on that date alone.

Early research suggests the coronavirus is mild in four out of five patients, however, it can trigger a disease called COVID-19. In addition, mild or even asymptomatic cases can later endure long COVID, lingering complications despite a coronavirus test coming back negative.

With nutrition known to affect our immune system, scientists from Northwestern University in Chicago investigated the extent to which our diet may keep us safe amid the pandemic.

Read more: Vegan diet cuts severe COVID risk by 73%

Results – published in the journal Nutrients – suggest drinking two to three cups of coffee a day lowers the risk of a positive coronavirus test by 10%, compared to less than one mug of the pick-me-up.

A high vegetable intake was also linked to a 12% lower risk of infection.

Coronavirus COVID-19 computer generated image.
The coronavirus is continuing to circulate despite lockdown restrictions having ended in England. (Stock, Getty Images)

"A person's nutrition impacts immunity and the immune system plays a key role in an individual's susceptibility and response to infectious diseases, including COVID-19," said study author Dr Marilyn Cornelis.

Read more: Green tea compound may combat severe COVID

"Besides following guidelines currently in place to slow the spread of the virus, we provide support for other relatively simple ways in which individuals can reduce their risk – and that is through diet and nutrition."

The Northwestern scientists analysed the dietary data of nearly 38,000 participants – aged 40 to 70 – of the UK Biobank study, self-reported between 2006 and 2010.

This information was linked to the participants' coronavirus test results, submitted to Public Health England from March to November, 2020 – before vaccines were rolled out.

Read more: Simple habits that could ward off coronavirus

Nearly two in five (17%) of the participants swabbed positive for the coronavirus via a polymerase chain reaction test, considered the gold-standard method of diagnosis.

The health pros and cons of coffee have long been debated. Although high in caffeine, the popular pick-me-up also contains anti-inflammatory and antioxidant compounds.

"Coffee is a major source of caffeine, but there are also dozens of other compounds that may potentially underlie the protective associations we observed," said Dr Cornelius.

The participants who ate among the highest amounts of vegetables were also 12% less likely to catch the coronavirus as those who consumed the least fresh produce.

Those who ate the most processed food were 14% more likely to test positive than those who consumed the least, the results show.

Perhaps surprisingly, being breastfed as a baby was linked to a 9% lower risk of catching the coronavirus in later life. Breastfeeding has long been associated with a stronger immune system.

The results remained the same after the scientists adjusted for each participant's estimated coronavirus exposure, based on where they lived. Other factors that raise the risk – like obesity and underlying health – were also accounted for.

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While lifestyle habits may play a role, officials have stressed vaccines are the most effective way of warding off coronavirus complications.

The Northwestern scientists have also pointed out the study was observational, and therefore does not prove cause and effect.

Nevertheless, they concluded: "Although these findings warrant independent confirmation, adherence to certain dietary behaviours may be an additional tool to existing COVID-19 protection guidelines to limit the spread of this virus."