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One Major Effect Coffee Has on Your Immune System, New Study Says

Researchers have found a powerful association between coffee and COVID-19 prevention.
FACT CHECKED BY Faye Brennan

How much do you love coffee—should we count the ways? Recently, we shared new insight about the beneficial effect of coffee on your liver health… but now, in perhaps an even more timely discovery, a team of medical researchers has just identified a strong link between how much coffee an individual drinks and how likely that person is to come down with COVID-19. We explain it.

In a study just published in the peer-reviewed scientific journal, Nutrients, a group of researchers at Northwestern University's Feinberg School of Medicine accessed dietary data on 38,000 participants from the UK's Biobank. Keep reading to learn what they found about the effect of coffee on your immune system; specifically in fighting COVID-19. Also, catch up on One Major Side Effect of Drinking Your Coffee Before Breakfast, Expert Says.

The researchers compared self-reported diet habits against COVID-19 infection records.

Patient is being tested in his vehicle on a drive-through coronavirus COVID-19 testing location
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To start, the researchers referred back to self-reported baseline diet data that 37,988 participants had shared for the UK Biobank between 2006 and 2010, when they each were between the ages of 40 and 70 years old. Then, the research team accessed COVID-19 test results of these same individuals via the U.K. government agency, Public Health England, from between March and November 2020.

RELATED: COVID Surging in These Hotspots, Experts Warn

Then, they looked at food groups.

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The researchers analyzed the participants' consumptions patterns of coffee, tea, processed meat, red meat, fish rich in omega-3 polyunsaturated fatty acids, fruit, and vegetables.

Coffee was strong.

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Of those foods and beverages, coffee came out among the top preventative dietary factors in preventing COVID-19. As the researchers reported, consumption of coffee—as well as vegetables—was "favorably associated with incident COVID-19." This means individuals who regularly had these two items saw a lesser chance of infection.

Looking at coffee specifically, the researchers reported that "habitual consumption of 1 or more cups of coffee per day was associated with about a 10% decrease in risk of COVID-19 compared to less than 1 cup/day."

This effect seems to be due to the nutritional benefits of coffee.

The researchers stated that the benefit of coffee in preventing COVID-19 comes down to science. They cited several past studies demonstrating other nutritional effects on immunity when they conclude:

Coffee is not only a key source of caffeine, but contributes dozens of other constituents; including many implicated in immunity. Among many populations, coffee is the major contributor to total polyphenol intake, phenolic acids in particular. Coffee, caffeine, and polyphenols have antioxidant and anti-inflammatory properties. Coffee consumption favorably correlates with inflammatory biomarkers … which are also associated with COVID-19 severity and mortality. Coffee consumption has also been associated with lower risk of pneumonia in elderly.

RELATED: One Surprising Effect Coffee Has on Your Hair, According to a Dermatologist

Another key insight about coffee and COVID-19 prevention, based on this study…

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Interestingly, the study found that coffee was associated with a lesser risk of COVID-19 infection even when individuals had been exposed to the virus.

RELATED: Dr. Fauci Just Issued New COVID Warning

Another beverage appeared to be worth drinking.

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The researchers state that "moderate tea" intake was also "significantly associated with lower odds of COVID-19 positivity."

RELATED: The #1 Best Green Tea to Drink, According to Experts

There was a third most significant diet factor in preventing COVID-19.

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Also shown to be associated with COVID-19 prevention? Having been breast-fed as a baby. (On the subject, be sure to read Alarming New Study Finds Harmful Chemicals From Food Packaging Are Present in Breast Milk.)

On the other hand…

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One particular food was clearly associated with higher risk of COVID-19 infection: Processed meat (which happens to be known for another major side effect, according to a recent study).

As if you needed another reason to love your coffee routine! Keep reading:

Krissy Gasbarre
Krissy is a senior news editor at Eat This, Not That!, managing morning and weekend news related to nutrition, wellness, restaurants and groceries (with a focus on beverages), and more. Read more