Overview: Even if you don’t suffer from typical food allergy symptoms, food allergens can affect your brain and behavior if you’re hypersensitive.
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The prevalence of food allergies is increasing globally and is approaching epidemic levels in some regions. In the United States alone, approximately 10% of children and adults suffer from food allergies, with allergies to milk, eggs, peanuts and tree nuts being the most common. Some patients have had mild symptoms that do not require medical attention, and these cases have not been reported.
Food allergies, or food sensitivities, result from an overreaction of the immune system to normally harmless proteins in food. They can manifest as a variety of symptoms, ranging from itching, redness, and swelling for mild reactions to vomiting, diarrhea, difficulty breathing, and other potentially life-threatening symptoms for severe reactions. .
In addition to self-reporting, food allergy can be diagnosed by exposing a patient by mouth or skin to minute amounts of the causative protein or allergen and observing the immediate reaction. More commonly, doctors use blood tests to measure levels of immunoglobulin E (IgE), a special antibody that the immune system uses to identify allergens and provoke a reaction.
Healthy people may have low IgE levels in their blood, but patients with food allergies have much higher levels that increase the risk of having a severe allergic reaction.
However, some people with a positive skin prick allergy test who have moderately elevated IgE levels may not notice any allergy-related symptoms when they eat the allergen. Also called sexual sensitization. In many cases, people with this condition may not even be aware that they have food sensitivities.
But are they really asymptomatic? Or are there effects in the body that they are unaware of?
I’m a neuroscientist who studies how the brain is affected by food allergies. I became interested in this topic when I found out that some members of my family were sensitive to cow’s milk. People who do not have severe allergic reactions occasionally eat dairy products and develop seemingly unrelated illnesses after a day or two.
What I and other researchers have discovered is that food allergens can affect the brain and behavior in cases of hypersensitivity, even without typical food allergy symptoms.
Food allergies associated with behavioral disorders
Researchers have suspected food sensitivities as a potential cause of behavioral disorders for decades.
A 1949 case report describes behavioral and mood disturbances in patients after eating certain foods such as milk and eggs. , suggesting that food sensitivity is likely to be the cause.
However, I was intrigued that patients were able to eat the offending foods until they chose to avoid them. I had the patience.
Several recent studies in people support an association between food allergies and various neuropsychiatric disorders such as depression, anxiety, attention-deficit/hyperactivity disorder, and autism. increase. They reinforce the possibility that reactions to food allergens involve the nervous system and manifest as behavioral disorders.
However, the idea that food sensitivities cause neuropsychiatric disorders remains controversial due to conflicting studies. may produce conflicting results.
More importantly, some studies included people with self-reported food allergies, while others only included people with laboratory-confirmed food allergies. This limited the investigation to symptomatic individuals only.
Food Sensitivity, Brain and Behavior
In my laboratory, we have tested whether food allergens manifest as behavioral symptoms, especially in asymptomatic sensitized individuals. We wanted to find out if eating the food causes brain inflammation and behavioral changes after sensitization.
We chose to use mice to minimize the individual differences found in human studies. We sensitized mice of the same age and genetic background to Ξ²-lactoglobulin (BLG), a common milk allergen, and fed them the same diet in the same room.
We found that BLG-sensitized mice produced moderate but significantly elevated levels of IgE but did not display immediate allergic reactions.
Eating foods containing the milk allergen for two weeks did not result in overt symptoms despite elevated IgE levels. was showing
Next, we observed whether there was a change in behavior driven by emotion. Since we were unable to ask the mice how they were feeling, we inferred their ’emotions’ by noting changes from their normal survival-oriented behavior. Rats instinctively explore their environment, seeking food and shelter while avoiding potential dangers.
However, “anxious” mice tend to spend more time hiding for safety. We identified ‘depressed’ mice by briefly holding them by the tail. Most mice will keep fighting to get out of their uncomfortable predicament, but depressed mice will give up quickly.
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Our experiment was designed to simulate a situation in which asymptomatically sensitized individuals eat either large amounts of the offending food per day or small amounts daily for several weeks.
We mimicked these situations by placing large amounts of the cow’s milk allergen directly into the stomach of sensitized mice via a feeding tube, or by giving them chow containing the allergen and sipping the allergen.
Interestingly, BLG-sensitized mice exhibited anxiety-like behavior one day after ingesting large amounts of allergens. Another group of sensitized mice exhibited depression-like behavior after eating small amounts of the allergen for two weeks.
Furthermore, BLG-sensitized mice showed signs of brain inflammation and neuronal damage, suggesting that brain changes may be responsible for behavioral symptoms.
We also investigated the long-term effects of allergen consumption by maintaining BLG-sensitized mice on an allergen-containing diet for 1 month. found that her IgE levels in sensitized mice dropped by the end of the month. In contrast, signs of inflammation in the brain persist, suggesting that the detrimental effects of the allergen remain in the brain.
chronic brain inflammation
Researchers have not yet studied long-term brain inflammation, or neuroinflammation, in people who are asymptomatically sensitized. Although known to cause diseases, the exact cause of these diseases is unknown.
A better understanding of the role allergens play in neuroinflammation will help researchers clarify whether food allergens cause chronic inflammation that can lead to these diseases.
This knowledge may be particularly important for patients undergoing oral immunotherapy.
The goal is to desensitize the immune system and reduce the incidence of anaphylaxis, or a life-threatening allergic reaction. Approved peanut allergen. However, the potential long-term effects on the nervous system are unknown.
Food allergens can affect the brain and behavior of seemingly asymptomatic people, making them less neurologically asymptomatic. The phrase βyou are what you eatβ takes on a whole new meaning.
About this allergy and psychology research news
author: Kumi Nagamoto – Combs
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contact: Kumi Nagamoto-Combs β The Conversation
image: image is public domain
