TOKYO, Japan — New hope is on the horizon for allergy sufferers. Researchers from Tokyo University of Science have discovered a vital connection between dietary fibers, gut health, and the immune system. The study reveals a complex interaction between short-chain fatty acids (SCFAs) — produced from dietary fibers by gut bacteria — and their significant anti-inflammatory and immunomodulatory effects.
SCFAs, found in plant-based foods, are metabolized by gut bacteria, leading to the production of molecules with potent effects on the body’s immune system. The focus of this research was on how these SCFAs influence mast cells (MCs), a type of white blood cell integral to allergic responses. MCs release histamine and other substances upon detecting foreign bodies, which can cause allergic reactions.
The Tokyo University team’s experiments provided compelling evidence that two specific SCFAs, butyric acid and valeric acid, could suppress allergic reactions in mice. The study further explored this effect in MC cultures, showing that SCFAs could prevent the activation of these cells, which typically leads to allergies. This was achieved through two main pathways: interaction with the GPR109A receptor, leading to the production of prostaglandins that hinder MC activation, and epigenetic changes that reduce the cells’ sensitivity to allergens.
This dual mechanism of action suggests that SCFAs can significantly dampen allergic responses, highlighting the importance of dietary fibers in managing allergies. The study also found that non-steroidal anti-inflammatory drugs could negate the beneficial effects of SCFAs, while vitamin B-3, known to interact with the GPR109A receptor, further inhibited MC degranulation.
“The activation of mast cell is a common cause of various allergic diseases and not limited to anaphylaxis,” says study lead author Chiharu Nishiyama, professor at Tokyo University of Science, in a university release. “In addition, I think that the increasing frequency of allergic patients is associated with changes in diet in these decades. Allergies are so common that one in two Japanese people is said to have some kind of allergic disease, and the results of our study showcase dietary fibers as an effective way of treating them.”
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In the United States, there are around 200,000 visits to the emergency room due to anaphylaxis. Tokyo University of Science researchers believe their work will be able to save lives and alleviate some of the burdens on the healthcare system.
The research underscores the complex interplay between diet, gut microbiota, and immune system regulation, providing a scientific basis for dietary recommendations aimed at preventing allergies. By focusing future studies on the relationship between specific SCFAs and the mucosal environment, the team hopes to uncover further health benefits of various foods, potentially leading to improved dietary guidelines and healthier lives.
“It is important to demonstrate with scientific evidence how dietary conditions affect health,” notes Nishiyama. “This research has revealed part of the complex regulatory mechanisms involving various food-related components, including dietary fiber, SCFAs, polyunsaturated fatty acids, and vitamins.”
The study is published in The Journal Of Immunology.