Skipping Breakfast can Trip Your Immunity

Fasting may be detrimental to combating illness and may raise the risk of heart disease. The study, which used mouse models, is one of the first to show that missing meals cause a brain reaction that harms immune cells. The findings, which focus on breakfast, may lead to a better understanding of how persistent fasting affects the body over time (1^✔ ✔Trusted Source
Monocytes re-enter the bone marrow during fasting and alter the host response to infection

Go to source). "There is a growing awareness that fasting is healthy, and there is indeed abundant evidence for the benefits of fasting. Our study provides a word of caution as it suggests that there may also be a cost to fasting that carries a health risk," says lead author Filip Swirski, Ph.D., director of the Cardiovascular Research Institute at Icahn Mount Sinai. "This is a mechanistic study delving into some of the fundamental biology relevant to fasting. The study shows that there is a conversation between the nervous and immune systems."

Fasting and Immune System

Researchers wanted to learn more about how fasting affects the immune system, from a short fast of a few hours to a longer fast of 24 hours. They looked at two groups of mice. The first group ate breakfast immediately after waking up (breakfast is their largest meal of the day), while the second group did not. Blood samples were taken from both groups of mice when they awoke (baseline), four hours later, and eight hours later.

As researchers examined the blood work, they observed a striking difference in the fasting group. The researchers saw a variation in the number of monocytes, which are white blood cells that are produced in the bone marrow and circulate throughout the body, where they serve a variety of important roles, from fighting infections to heart disease to cancer.

All mice had the same number of monocytes at the start. Monocytes in mice from the fasting group, on the other hand, were significantly altered after four hours. Researchers discovered that 90% of these cells vanished from the bloodstream within eight hours, and the number continued to fall. Monocytes in the non-fasting group, on the other hand, were unaffected.

Researchers discovered that in hungry mice, monocytes returned to the bone marrow to hibernate. Likewise, bone marrow cell production has decreased.

Monocytes in the bone marrow, which have a short lifespan, were considerably altered. They lived longer because they were in the bone marrow, and they aged differently than monocytes in the blood.

The researchers fasted the mice for up to 24 hours before reintroducing food. Within a few hours, the cells that had been hidden in the bone marrow were released into the bloodstream. This rise resulted in increased inflammation. Instead of protecting the body from infection, these changed monocytes were more inflammatory, making them less resistant to infection.

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This is one of the first studies to establish a link between the brain and these immune cells when fasting. The researchers discovered that certain brain areas influenced the monocyte response during fasting.

Fasting causes a stress reaction in the brain, which is what causes people to feel "hangry" (hungry and furious), and this immediately initiates a large-scale migration of these white blood cells from the blood to the bone marrow and then back to the bloodstream shortly after a food is reintroduced.

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While there is evidence of the metabolic benefits of fasting, Dr. Swirski emphasizes that this new study is a useful development in the entire knowledge of the body's systems.

The Affect of Fasting on Body

"The study shows that, on the one hand, fasting reduces the number of circulating monocytes, which one might think is a good thing, as these cells are important components of inflammation.

On the other hand, the reintroduction of food creates a surge of monocytes flooding back into the blood, which can be problematic. Fasting, therefore regulates this pool in ways that are not always beneficial to the body’s capacity to respond to a challenge such as an infection," explains Dr. Swirski. "Because these cells are so important to other diseases like heart disease or cancer, understanding how their function is controlled is critical."

Reference:

1. Monocytes re-enter the bone marrow during fasting and alter the host response to infection - (https://www.sciencedirect.com/science/article/abs/pii/S1074761323000365)

Source-Medindia