According to a Mount Sinai study, fasting in mouse models can have a detrimental impact on the body's ability to fight illness.
A recent study from the Icahn School of Medicine at Mount Sinai suggests that fasting may be harmful for fighting off illness and may raise the risk of heart disease. The study, which concentrated on mouse models, is one of the first to demonstrate that skipping meals causes the brain to react in a way that harms immune cells. The findings, which centre on breakfast, were released in the Immunity journal on February 23 and may help researchers better understand how long-term fasting may influence the body.
Scientists were interested in learning more about how fasting, from a mild few-hour fast to a more severe 24-hour fast, affected the immune system.
Importance of breakfast and immune system
Two mouse groups were examined. The major meal of the day for one group, breakfast, was consumed immediately after waking up, while breakfast was skipped by the other. When the mice first awoke in both groups (baseline), four hours later, and eight hours later, blood samples were taken.
The fasting group showed a clear change in the blood test, according to the researchers. The quantity of monocytes, which are white blood cells produced in the bone marrow and circulate throughout the body and play a variety of vital roles in everything from fighting infections to heart disease to cancer, was specifically where the researchers noticed a difference.
All mice had an equal number of monocytes at the beginning.
Monocytes in the mice from the fasting group, however, were significantly impacted after four hours.
Ninety percent of these cells were discovered to have vanished from the bloodstream, and at eight hours, the number continued to fall.
The non-fasting group’s monocytes, however, were unaffected.
Researchers found that during fasting, monocytes returned to the bone marrow to hibernate. The bone marrow’s capacity to produce new cells also declined at the same time. The bone marrow’s normally transient monocytes underwent considerable alteration. They aged differently than the monocytes that remained in the blood and lived longer as a result of remaining in the bone marrow.
After fasting the mice for up to 24 hours, the researchers reintroduced food. Within a few hours, the cells that were hiding in the bone marrow exploded back into the bloodstream. This increase caused the inflammation to increase. These changed monocytes were more inflammatory than anti-infective, weakening the body’s ability to fight infection.
Relationship between the brain & immune cells during fasting
The relationship between the brain and these immune cells during fasting has just recently been discovered, according to this study. Researchers discovered that some parts of the brain were in charge of regulating the monocyte response to fasting.
This study showed that fasting causes the brain to go into a stress response, which is what causes people to feel “hangry” (hungry and angry). This immediately causes a large-scale migration of these white blood cells from the blood to the bone marrow, and they return to the bloodstream shortly after food is consumed.
The researchers underlined that although there is evidence for the metabolic advantages of fasting as well, this new study represents an important step forward in our knowledge of the body’s systems.
The National Institutes of Health and the Cure Alzheimer’s Foundation provided money to support this study.
Parvathy Sukumaran 
