Why skipping breakfast can compromise the immune system

Specialists ensure that an intermittent breakfast should not be carried out without professional follow-up

Diet profoundly influences people’s health. And just as overnutrition raises disease risk through its influence on immunity and metabolism, caloric restriction and fasting appear not to be as beneficial as is believed.

According to a recent study by researchers at the Icahn School of Medicine at Mount Sinai, fasting may be detrimental in fighting infections and could lead to an increased risk of heart disease.

The research, the results of which were published in the February 23 issue of Immunity, focused on mouse models and is among the first to show that skipping meals triggers a response in the brain that negatively affects immune cells. According to the researchers, their findings could lead to a better understanding of how chronic fasting can affect the body in the long term.

“We identified a fasting-induced change in leukocyte migration that prolongs monocyte lifespan and alters disease susceptibility in mice,” the authors of the paper noted in publishing their conclusions. We show that fasting during the active phase induced the rapid return of monocytes from the blood to the bone marrow.”

In the study, the researchers sought to better understand how fasting, from a relatively short fast of a few hours to a more severe 24-hour fast, affects the immune system.

To do so, they analyzed two groups of mice: one group ate breakfast immediately after waking up, and the other group did not. The researchers collected blood samples from both groups when the mice woke up, then four hours later and eight hours later.

When examining the laboratory results they noted a clear difference in the fasting group. Specifically, the researchers saw a difference in the number of monocytes, which are white blood cells that are made in the bone marrow and travel throughout the body, where they perform many critical functions, from fighting infections to heart disease and cancer.

Filip Swirski is the study’s lead author, Ph.D., and director of the Institute for Cardiovascular Research at Icahn Mount Sinai, remarking that “there is increasing awareness that fasting is healthy and, in fact, there is abundant evidence of the benefits of fasting.

“Our study offers a caveat, as it suggests that fasting may also come at a cost that carries a health risk,” he said. This is a mechanistic study that delves into some of the fundamental biology relevant to fasting. The study shows that there is a conversation between the nervous and immune systems.”

The work is one of the first to establish the connection between the brain and these immune cells during fasting. The researchers found that specific regions of the brain controlled the monocyte response during fasting, so they deduced that “fasting causes a stress response in the brain, that’s what makes people hungry, which instantly triggers a large-scale migration of these white blood cells from the blood to the bone marrow, and then back into the bloodstream shortly after food is reintroduced.