Researchers discovered that people with milk allergies often have mood and behavior problems because of a chemical called histamine that builds up in the brain. In a study with mice, scientists tested a drug called thioperamide that blocks histamine’s effects in the brain. The drug helped reduce depression-like behavior and brain damage in male mice with milk allergies. This research suggests that treating the histamine problem in the brain might help people with milk allergies feel better emotionally, though more research in humans is needed to confirm these findings.

The Quick Take

  • What they studied: Whether a drug that blocks a brain chemical called histamine could improve mood problems and brain damage in mice with cow’s milk allergies
  • Who participated: Male and female laboratory mice that were specially bred to have subclinical cow’s milk allergies (allergies that don’t show obvious symptoms)
  • Key finding: The drug thioperamide reduced depression-like behavior and brain inflammation in male mice with milk allergies, though it affected male and female mice differently
  • What it means for you: If confirmed in humans, this could lead to new treatments for people with milk allergies who also experience mood problems like depression. However, this is early-stage research in animals, so it may be years before any human treatments are available

The Research Details

Scientists used laboratory mice that were genetically similar to humans and specially treated to develop milk allergies. They divided the mice into groups and gave some of them a drug called thioperamide while feeding all of them a diet containing milk protein. The researchers then tested the mice’s behavior using standard tests that measure depression-like symptoms, anxiety, and thinking ability. They also examined the mice’s brains under a microscope to look for inflammation and damage to the protective coating around nerve fibers.

The study lasted two weeks, which is a relatively short time frame. The researchers carefully tracked behavioral changes and compared results between male and female mice to see if the drug worked differently depending on sex. They also looked at immune cells called mast cells in the brain’s protective membrane to understand how the drug was working.

This research approach is important because it tests a specific theory about how allergies affect the brain. Rather than just observing that people with allergies have mood problems, the scientists investigated the actual mechanism—whether a specific brain chemical called histamine is responsible. By testing a drug that targets this chemical, they could prove whether fixing the histamine problem would fix the behavior problems. This type of research helps scientists understand the root cause of symptoms rather than just treating the symptoms themselves.

This study was published in a peer-reviewed scientific journal, meaning other experts reviewed it before publication. However, the research was conducted only in mice, not humans, so results may not directly apply to people. The study included both male and female mice, which is good because it shows the drug works differently in males and females. The researchers used established behavioral tests that are recognized by the scientific community. One limitation is that the sample size wasn’t specified in the available information, making it harder to assess statistical reliability.

What the Results Show

The main finding was that thioperamide reduced depression-like behavior in male mice with milk allergies. Male mice that received the drug showed improvements in mood-related behaviors compared to male mice that didn’t receive it. The drug appeared to work by blocking histamine’s effects in the brain, which reduced inflammation and helped protect nerve fibers from damage.

Interestingly, the drug affected male and female mice differently. While male mice showed clear improvements in behavior and brain health, female mice responded differently to the treatment. This sex-based difference is important because it suggests that the underlying biology of how allergies affect the brain may be different between males and females.

The researchers also found that male mice with milk allergies had more activated immune cells (mast cells) in the brain’s protective membrane compared to females. However, the drug didn’t reduce these immune cells in either sex, suggesting it worked through a different mechanism to improve behavior.

The study found that sensorimotor functions—basic movement and coordination—were not impaired in either male or female mice with milk allergies, suggesting that the milk allergy primarily affected mood and thinking rather than physical movement. The research also confirmed that milk allergies do indeed cause inflammation in the brain and damage to the protective coating around nerve fibers, which had been suspected but not clearly proven before. Additionally, the findings suggest that the histamine system in the brain plays a key role in connecting allergic reactions in the body to mood changes in the brain.

This research builds on earlier work by the same team showing that mice with milk allergies have elevated histamine levels in their brains and show depression-like behavior. The new study goes further by testing whether blocking histamine’s effects can reverse these problems. The findings align with clinical observations that people with food allergies often report mood and anxiety problems, though this is the first study to directly test a treatment targeting the histamine mechanism in the brain. The sex-dependent effects are particularly novel and suggest that previous research may have missed important differences between males and females.

This study was conducted only in mice, not humans, so the results may not directly translate to people with milk allergies. The study lasted only two weeks, which is a short time frame for understanding long-term effects. The exact number of mice used wasn’t specified, making it difficult to assess the statistical strength of the findings. The drug was given to mice that had subclinical allergies (allergies without obvious symptoms), so it’s unclear whether it would work for people with more severe allergic reactions. Additionally, the study doesn’t explain why the drug worked differently in male versus female mice, which limits our understanding of how to apply these findings to different populations.

The Bottom Line

Based on this research, there is currently no recommendation to use thioperamide or similar drugs in humans, as this is early-stage animal research. However, this study suggests that future human trials investigating histamine-blocking drugs for people with food allergies and mood problems may be worthwhile. Anyone with milk allergies experiencing mood or behavioral changes should discuss this with their doctor, though current treatment options remain allergy avoidance and standard mood disorder treatments. Confidence level: Low, as this is preliminary animal research.

This research is most relevant to people with cow’s milk allergies who also experience depression, anxiety, or other mood problems. It may also interest researchers studying the connection between allergies and mental health, and healthcare providers treating patients with both conditions. People without milk allergies or those with milk allergies but no mood symptoms may find this less immediately relevant. This research is not yet applicable to clinical practice but may inform future treatment development.

In this mouse study, behavioral improvements were observed within two weeks of treatment. However, if this research eventually leads to human treatments, it would likely take 5-10 years of additional research, clinical trials, and regulatory approval before any new drug becomes available. Even then, individual responses would vary, and it’s unclear how quickly benefits would appear in humans compared to mice.

Want to Apply This Research?

  • Users with milk allergies could track their mood daily using a simple 1-10 scale, noting any correlation with milk consumption or allergy symptoms. They could also log anxiety levels, sleep quality, and energy levels to identify patterns between allergic reactions and mood changes.
  • Users could use the app to maintain a detailed food and mood diary, documenting when they consume milk products and any subsequent mood or behavioral changes. This data could help them and their healthcare provider identify whether their mood problems are connected to their milk allergy, potentially supporting discussions about future treatment options.
  • Over several weeks, users could track whether avoiding milk products improves their mood, and share this information with their doctor. If new treatments become available, the app could help monitor whether medications improve both allergy symptoms and mood, providing objective data to discuss with healthcare providers about treatment effectiveness.

This research was conducted in laboratory mice and has not been tested in humans. The findings are preliminary and should not be used to guide personal medical decisions. If you have a milk allergy and are experiencing mood or behavioral changes, please consult with your healthcare provider or a mental health professional. Do not start, stop, or change any medications without medical supervision. This article is for educational purposes only and does not constitute medical advice.