Aug. 10, 2022 – Intermittent fasting was not linked with a smaller chance of getting COVID-19, but it was linked with getting a less severe infection, according to the findings of a new study.

The study was done on men and women in Utah who were, on average, in their 60s and got COVID before vaccines were available.

Roughly 1 in 3 people in Utah fast from time to time – higher than in other states. This is partly because more than 60% of people in Utah belong to the Church of Jesus Christ of Latter-day Saints, and roughly 40% of them fast – typically skipping two meals in a row.

Those who fasted, on average, for a day a month over the past 40 years were not less likely to get COVID, but they were less likely to be hospitalized or die from the virus.

"Intermittent fasting has already shown to lower inflammation and improve cardiovascular health," lead study author Benjamin Horne, PhD, of Intermountain Medical Center Heart Institute in Salt Lake City, said in a statement.

"In this study, we’re finding additional benefits when it comes to battling an infection of COVID-19 in patients who have been fasting for decades,” he said.

The study was published in BMJ Nutrition, Prevention & Health.

Intermittent Fasting Not a Substitute for a COVID-19 Vaccine

Importantly, intermittent fasting shouldn’t be seen as a substitute for getting a COVID vaccine, the researchers stress. Rather, periodic fasting might be a health habit to consider, since it is also linked to a lower risk of diabetes and heart disease, for example.

But anyone who wants to consider intermittent fasting should consult their doctor first, Horne stressed, especially if they are elderly, pregnant, or have diabetes, heart disease, or kidney disease.

Fasting Didn’t Prevent COVID-19 but Made It Less Severe

In their study, the team looked at data from 1,524 adults who were seen in the cardiac catheterization lab at Intermountain Medical Center Heart Institute, completed a survey, and had a test for the virus that causes COVID-19 from March 16, 2020, to Feb. 25, 2021.

Of these patients, 205 tested positive for COVID, and of these, 73 reported that they had fasted regularly at least once a month.

Similar numbers of patients got COVID-19 whether they had, or had not, fasted regularly (14%, versus 13%).

But among those who tested positive for the virus, fewer patients were hospitalized for COVID or died during the study follow-up if they had fasted regularly (11%) than if they had not fasted regularly (29%).

Even when the analyses were adjusted for age, smoking, alcohol use, ethnicity, history of heart disease, and other factors, periodic fasting was still an independent predictor of a lower risk of hospitalization or death.

Several things may explain the findings, the researchers suggest.

A loss of appetite is a typical response to infection, they note.

Fasting reduces inflammation, and after 12 to 14 hours of fasting, the body switches from using glucose in the blood to using ketones, including linoleic acid.

"There’s a pocket on the surface of SARS-CoV-2 that linoleic acid fits into – and can make the virus less able to attach to other cells,” Horne said.

Intermittent fasting also promotes autophagy, he noted, which is "the body’s recycling system that helps your body destroy and recycle damaged and infected cells."

The researchers conclude that intermittent fasting plans should be investigated in further research "as a complementary therapy to vaccines to reduce COVID-19 severity, both during the pandemic and post pandemic, since repeat vaccinations cannot be performed every few months indefinitely for the entire world and vaccine access is limited in many nations."

Show Sources

Intermountain Healthcare: "New Intermountain Healthcare Study Finds People Who Practice Intermittent Fasting Experience Less Severe Complications from COVID-19."

BMJ Nutrition, Prevention & Health: "Association of periodic fasting with lower severity of COVID-19 outcomes in the SARS-CoV-2 prevaccine era: an observational cohort from the INSPIRE registry"

Intermountain Healthcare Biological Samples Collection Project and Investigational Registry (INSPIRE).

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