Researchers discover surprising link between dishwashers and chronic illnesses

A recent study has unveiled the harmful effects of an ingredient in commercial rinse agents on the gastrointestinal tract.

Residue from rinse agents is left behind on dishes after they are cleaned in professional-grade dishwashers.

Residue from rinse agents is left behind on dishes after they are cleaned in professional-grade dishwashers. (CREDIT: Creative Commons)

A recent study by researchers at the Swiss Institute of Allergy and Asthma Research (SIAF), linked with the University of Zurich (UZH), has unveiled the harmful effects of an ingredient in commercial rinse agents on the gastrointestinal tract. This discovery has significant public health implications, as the toxic substance may initiate various chronic diseases.

Commercial dishwashers, commonly used in settings such as restaurants and barracks, wash plates, glasses, and cutlery through a two-step process. The first step involves a 60-second high-pressure cycle with hot water and detergent. The second step is another 60-second cycle where water and a rinse agent are applied.

The study found that many dishwashers lack an extra wash cycle to remove leftover rinse aid, allowing potentially toxic substances to dry on the dishes. When these dishes are reused, the dried chemical residue can easily enter the gastrointestinal tract.

The research, led by Cezmi Akdis, UZH professor of experimental allergology and immunology and director of SIAF, examined the impact of components in commercial-grade detergents and rinse agents on the gut's epithelial barrier. This barrier, a layer of cells lining the intestinal tract, regulates what enters the body. Defects in this barrier are linked to conditions such as food allergies, gastritis, diabetes, obesity, liver cirrhosis, rheumatoid arthritis, multiple sclerosis, autism spectrum disorders, chronic depression, and Alzheimer’s disease.

Dose-dependent cytotoxicity in Caco-2 cells in response to professional dishwasher detergent and rinse aid. A, Cytotoxicity of monolayer-cultured Caco-2 cells treated with professional dishwasher detergent and rinse aid alone or as a mixture for 24 hours in different dilutions. (CREDIT: The Journal of Allergy and Clinical Immunology)

The study utilized human intestinal organoids and intestinal cells on microchips, a cutting-edge technology that forms a three-dimensional clump of cells resembling the human intestinal epithelium. Using various biomolecular methods, the team analyzed the effects of commercial detergents and rinse aids on these cells, diluting the substances to concentrations that would be present on dry dishes (1:10,000 to 1:40,000).

The results revealed that high doses of rinse agents killed the intestinal epithelial cells, while lower doses made the barrier more permeable. This increased permeability was accompanied by the activation of several genes and cell signaling proteins that could provoke inflammatory responses. A more in-depth analysis identified alcohol ethoxylates, a component of the rinse agent, as the culprit.

The researchers warn that this effect could lead to the gradual destruction of the gut's epithelial layer, potentially triggering numerous chronic diseases. Akdis emphasizes the need for public awareness and immediate action: “It is important to inform the public about this risk, since alcohol ethoxylates seem to be commonly used in commercial dishwashers.”

The connection between defective epithelial barriers and chronic illnesses has been explored in many studies. Akdis, who has over 20 years of research experience in this field, explains that various additives and chemicals encountered in daily life can damage these layers. “We assume that defective epithelial barriers play a role in triggering the onset of two billion chronic illnesses,” he says. This correlation is supported by the epithelial barrier hypothesis, a concept Akdis has contributed to significantly.

The rinse aid decreased TEER and increased PF in differentiated Caco-2 cells. A, C, and E, TEER was measured every 24 hours for 9 days for cells treated with detergent and rinse aid alone or as a mixture. B, D, and F, PF was measured in response to 72 hours of exposure to the detergent and rinse aid alone or as a mixture. (CREDIT: The Journal of Allergy and Clinical Immunology)

The findings underscore the importance of addressing the risks associated with commercial dishwashers, which are prevalent in many environments. The toxic effects of rinse agents on the gastrointestinal tract highlight the need for immediate public health interventions to mitigate the potential onset of chronic diseases.

These findings call for urgent public health measures to protect individuals from the harmful effects of these substances, particularly given their widespread use in dishwashers. The research highlights the critical role of the epithelial barrier in maintaining health and preventing chronic diseases, urging further exploration and mitigation of risks associated with everyday chemical exposures.

Literature:

Ismail Ogulur, Yagiz Pat, Tamer Aydin, Duygu Yazici, Beate RĂĽckert, Yaqi Penq, Juno Kim, Urszula Radzikowska, Patrick Westermann, Milena Sokolowska, Raja Dhir, Mubeccel Akdis, Kari Nadeau, Cezmi A. Akdis. Gut epithelial barrier damage caused by dishwasher detergents and rinse aids. The Journal of Allergy and Clinical Immunology.



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Joseph Shavit
Joseph ShavitSpace, Technology and Medical News Writer
Joseph Shavit is the head science news writer with a passion for communicating complex scientific discoveries to a broad audience. With a strong background in both science, business, product management, media leadership and entrepreneurship, Joseph possesses the unique ability to bridge the gap between business and technology, making intricate scientific concepts accessible and engaging to readers of all backgrounds.