Digging the root | Is picky eating a "bad habit"? Subverted! Picky eating may be a way for the immune system to protect the body!

gossip

"If you don't eat, you won't grow taller."

"You don't want to eat this, and you don't want to eat that, so don't eat it!"

When we were young, we were often criticized for being picky eaters. Many people have always believed that being picky eaters is a "bad habit" because it may limit an individual's nutritional intake and may even cause embarrassment in social situations.

However, the latest scientific research provides a new explanation and understanding for the phenomenon of picky eating.

analyze

Recently, two studies published in the journal Nature revealed a surprising fact: picky eating may not only be a matter of personal taste, but our immune system is at work to help us avoid consuming potentially harmful foods. This discovery not only overturns our traditional understanding of picky eating, but also opens up a new perspective for us to understand and utilize this phenomenon.

Allergies trigger a disgust response, prompting food avoidance

Researchers at Yale University sensitized mice with ovalbumin (OVA) (that is, they were made to have an allergic reaction the next time they encountered OVA). They found that the sensitized mice licked ovalbumin less frequently and preferred to lick water. However, the non-sensitized control group mice did not have this phenomenon and licked ovalbumin more frequently than water. [1]

From reference [1]

A single allergen challenge can activate the nucleus tractus solitarius (NTS), lateral parabrachial nucleus (elPBN), and central amygdala (CeA) in the mouse brain, which are involved in aversive responses to unpleasant stimuli. [1]

From reference [1]

These explain why the sensitized mice were reluctant to touch ovalbumin, but how does ovalbumin located in the intestine stimulate activation of brain areas?

Here we have to mention mast cells in the intestinal immune response.

A complex mechanism with mast cells at its core

Researchers at Heidelberg University[2] uncovered the mystery through experiments.

(1) Mast cells play a central role

The researchers used non-sensitized mice, sensitized mice that lacked mast cells, and sensitized normal mice for comparison and found that:

Unsensitized mice showed a strong preference for water containing ovalbumin, regardless of mast cell deficiency;

Sensitized normal mice, which almost exclusively chose to drink regular water, would avoid drinking water containing ovalbumin;

Mice that were sensitized but lacked mast cells did not show avoidance behavior toward water containing ovalbumin. The study also found that the number of mast cells in the stomach and small intestine of normal mice after immunization increased significantly, especially in the epithelial cells of the small intestine.

From reference [2]: Each dot represents a mouse

(2) Mast cells regulate avoidance behavior through the immune-brain axis

Mast cells display a diverse and complex mechanism in regulating avoidance behavior, rather than relying on a single factor. After ingesting allergens, mast cells not only work closely with IgE, but also work together with elements such as leukotrienes and Th2 cytokines to promote this process.

Even more strikingly, the researchers proposed an unprecedented theory that there may be an "immune-brain axis" in which mast cells are able to communicate with the brain and thus directly influence the individual's behavior.

Results should be interpreted with caution

There is still a long way to go from mice to humans

These two studies provide us with a whole new perspective on the phenomenon of picky eating. It is no longer a simple "bad habit", but a complex biological mechanism through which our bodies can identify and avoid substances that may be harmful to us.

This new understanding opens up a new area of ​​research that may help us better understand and exploit this natural protective mechanism. It also provides us with a more scientific and rational perspective on picky eating and may lead to more personalized and effective nutrition and dietary advice.

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However, we still need to interpret the conclusions of these two studies with caution, because they were both conducted on mouse models, which may deviate from the mechanisms in humans, which means we need more time and research to determine whether these findings can be directly applied to humans.

in conclusion

These two studies have overturned the public's traditional view of picky eating and provided us with a more scientific and rational perspective on picky eating. However, the experiments are currently only conducted on mouse models, and whether they can be directly applied to humans still needs further research by scientists.

However, what can inspire us is that when children do not want to eat a certain food, perhaps we can try not to force them, but to find a safer and more delicious food as a substitute.

Author: Mr. Ayuan, an internist

Reviewer: Wang Qiang, deputy chief physician, Department of Gastroenterology, Peking Union Medical College Hospital

References:

[1] Florsheim EB, Bachtel ND, Cullen JL, et al. Immune sensing of food allergens promotes avoidance behavior. Nature. 2023;620(7974):643-650.

[2]Plum T, Binzberger R, Thiele R, et al. Mast cells link immune sensing to antigen-avoidance behavior. Nature. 2023;620(7974):634-642.

Planning丨Zhong Yanping

Editor: Zhong Yanping

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