Fasting may compromise the immune system, study finds

Skipping meals triggers a response in the brain that negatively affects immune cells, according to a study in mice, which finds that fasting may be detrimental to fighting infections and lead to an increased risk of heart disease.

Source: Efe

The research, focused on breakfast and led by the Icahn School of Medicine at Mount Sinai (United States), is published in the journal Immunity and could help to better understand how chronic fasting can affect the body in the long term, the authors point out.

“There is increasing awareness that fasting is healthy and, in effect, there are abundant evidence of its benefits. Our study offers a caveat, suggesting that fasting may also come at a cost that carries a health risksays lead author Filip Swirski.

The work shows that there isA conversation between the nervous and immune systems”he adds in a statement.

The goal was to better understand how fasting—from a relatively short fast of just a few hours to a more severe 24-hour fast—affects the immune system.

For it, the scientists analyzed two groups of mice. One group ate breakfast as soon as they woke up (breakfast in this experiment was the largest meal of the day) and the other group did not.

The researchers collected blood samples from both groups when the mice woke up, four hours later, and eight hours later. When they examined them, they saw a clear difference in the fasting group.

Specifically, they found a difference in the number of monocytes, white blood cells that are produced in the bone marrow and travel throughout the body, where they perform many critical functions, from fighting infections to heart disease and cancer.

At the beginning, all the mice had the same number of monocytes, but after four hours, these white blood cells of the mice in the fasting group were drastically affected.

The researchers found that 90 percent of these cells disappeared from the bloodstream, and the number was still declining at eight hours; on the other hand, the monocytes of the group that did not fast were not affected.

In the fasting mice, the researchers found that the monocytes returned to the bone marrow to hibernate; there they survived longer and aged differently than the monocytes that remained in the blood.

In addition, they found that the production of new blood cells in the bone marrow decreased.

The experiment The mice were fasted for 24 hours and then fed.

The hidden cells in the bone marrow then returned to the bloodstream within a few hours, an increase that led to further inflammation.

Instead of protecting against infection, these altered monocytes were more inflammatory, making the body less resistant to fighting infection.

This studio is one of the first to establish the connection between the brain and these immune cells during fasting, the authors saywho discovered that specific brain regions controlled the monocyte response during fasting.

Research showed that fastingor it causes a stress response in the brain (it’s what makes people feel hungry and angry), which instantly triggers a large-scale migration of these white blood cells into the bone marrow, and then back into the bloodstream shortly after food is reintroduced.

“While there is also evidence for the metabolic benefits of fasting, this new study represents a useful advance in the full understanding of the body’s mechanisms,” concludes Swirski.