Could a hot cup of matcha stop you from sneezing?

Hay fever sufferers have attempted various treatments and techniques. They have tried antihistamines, nasal sprays, air purifiers, and staying indoors when pollen counts are at their highest. The number of partial solutions is extensive. A recent study by Hiroshima University in Japan, however, indicates a very nonclinical solution: matcha, the finely powdered green tea originating in Japan and used in everything from lattes to baked goods.

Professor Osamu Kaminuma from the Research Institute for Radiation Biology and Medicine conducted the research. He discovered that after receiving matcha over a course of several weeks, mice engineered to express symptoms of hay fever showed a dramatic decrease in sneezing. The amount was reduced to almost zero.

What was more remarkable was where the effect seemed to originate. It did not appear to originate from any immune response.

Also known as allergic rhinitis, hay fever is typically classified as an issue of the immune system. Allergens enter through the nasal passages and cause the body to trigger an excessive response. This leads to a chain of events including the release of IgE antibodies, mast cells, and T cells.

These substances are the target of most current treatments for hay fever. Overall, the matcha had no impact on any of these immune responses.

The study’s authors did not find any change in the amount of IgE antibodies, mast cells, or T cells present in the treated mice compared to the untreated mice after they consumed matcha. Furthermore, none of the other theories for how matcha could potentially work to treat hay fever could be substantiated by the data collected from the study.

All of the usual pathways checked by the authors came back negative. Instead, they observed activity in the brainstem.

“The fact that consuming matcha by mouth resulted in less sneezing when there was not a notable difference in the major immune markers,” Kaminuma noted. “On the contrary, it greatly reduced the activation of neurons in the brainstem responsible for the sneeze reflex.”

The researchers examined a part of the brainstem called the ventral spinal trigeminal nucleus. This area of the brainstem processes signals from the nose and helps trigger sneezing.

Researchers measured neurological activity by examining how much the brain region lit up through the use of c-FOS, a gene that indicates how active a neuron is. This measurement was conducted in allergic mice when they were presented with allergens.

When c-FOS levels were examined in the brains of untreated allergic mice, activity in this area increased dramatically from normal levels. When the mice were given matcha, the amount of c-FOS activity remained close to its baseline level.

This finding indicates that the neural signal responsible for sneezing weakened before it could reach its full activation level.

Matcha differs from regular green tea. Regular green tea is brewed by steeping tea leaves in hot water and discarding the used leaves. In contrast, matcha is produced by grinding the entire leaf into a fine powder.

Consuming matcha means ingesting the entire tea leaf rather than only the brewed extract. Because of this, a larger amount of bioactive compounds found in green tea can be absorbed by the body.

Research has previously shown that some compounds found in matcha, such as catechins, L-theanine, caffeine, and various polyphenols, produce neurological effects. Matcha has also been shown to reduce stress responses in clinical studies and animal models through changes to the autonomic nervous system.

The sneeze reflex can be influenced by either the autonomic nervous system or nerve activity. This provides one possible explanation for how matcha could affect the response.

Part of Kaminuma’s research investigated whether matcha reduced sneezing caused by histamine or by a compound called substance P in healthy mice. Matcha appeared to reduce sneezing caused by both substances. However, the results were not statistically significant and had several limitations.

The experimental design followed a structured approach. Mice were sensitized to a common allergen over four weeks through injections.

After that period, the mice were exposed to the allergen directly through the nose for five consecutive days to induce symptoms of hay fever. The mice received matcha extract orally two to three times per week for five weeks prior to allergy exposure.

After receiving the matcha extract, the mice showed a decrease in immediate sneezing after allergen exposure. Nasal hyperresponsiveness following exposure was also reduced.

There were no changes in general health or body weight in the mice during the duration of the study.

Kaminuma cautioned against making overly broad conclusions from the study. The findings are limited to experiments conducted in mice.

Hay fever in humans involves similar physiological mechanisms to those seen in mice. However, whether matcha affects the neural response to allergens in the same way in humans remains unproven.

Sample sizes in some assays were small. Larger and more statistically powered studies will be required before the findings can support clinical use.

“The goal is to find a way to help provide food-based options that improve or complement current treatments of allergic rhinitis symptoms,” Kaminuma said.

This research helps guide future studies aimed at developing food-based therapies for allergic rhinitis. The intention is not to replace standard treatments such as antihistamines or other medications. Instead, researchers aim to explore whether certain foods may provide complementary benefits through mechanisms not previously considered in allergy treatment.

If the findings are proven effective in humans, neural suppression of the sneeze reflex could offer people with allergic rhinitis another method of managing their condition.

Most current therapies target immune responses. They focus on systemic immune pathways and reduce inflammation after the allergic response has already begun.

A food-based compound that prevents the neuron-driven sneeze reflex before the inflammatory cascade begins would represent a different approach to treatment.

If confirmed, the findings could benefit roughly 400 million people worldwide who suffer from allergic rhinitis. Matcha is widely available and generally recognized as safe for regular consumption.

Translating laboratory results into practical treatments will require additional research. However, the mechanism identified in this study highlights a previously unexplored direction for allergic rhinitis research.

Research findings are available online in the journal npj Science of Food.

The original story "Could a hot cup of matcha stop you from sneezing?" is published in The Brighter Side of News.

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