Commercial dishwashers can damage the intestines and lead to chronic disease

According to researchers at the Swiss Institute for Allergy and Asthma Research who work with organelles, rinsing aid residue on dishes after washing them in specialized dishwashers can damage the natural protective layer of the gut and contribute to the development of chronic disease.

Commercial dishwashers are a convenient way to quickly clean and dry dishes, cups, and cutlery in a variety of settings, such as restaurants, schools, and barracks. However, a recent study by researchers at the Swiss Institute for Allergy and Asthma Research (SIAF), an institute associated with the University of Zurich (UZH), revealed that these devices do have risks. The study found that an ingredient in commercial rinse aids has a toxic effect on the digestive system.

Chemical residues on clean panels

The typical cycle in a commercial dishwasher involves circulating hot water and detergent for 60 seconds at high pressure. This is followed by a second wash and dry cycle of 60 seconds in which water and rinse aid are applied. “Particularly concerning is that in many devices there is no additional washing cycle to remove remaining rinse aid,” says Sesme Akdis, professor of allergy and experimental immunology at the University of Uzbekistan and director of SIAF, who led the study. “This means that potentially toxic substances remain on the dishes, where they then dry in place.” When you use the dishes next time, this dry chemical residue can easily end up in your digestive tract.

This inspired the Akdis research team to investigate the effect of ingredients in commercial detergents and rinse aids on the epithelial barrier of the intestine, which is the layer of cells that lines the intestines and controls what enters the body. A defect in this barrier is associated with conditions such as food allergies, gastritis, diabetes, obesity, cirrhosis, rheumatoid arthritis, multiple sclerosis, autism spectrum disorders, chronic depression, and[{” attribute=””>Alzheimer’s disease.

Similar protective layers are also present on the skin and in the lungs. As numerous studies have shown, many additives and chemicals that we encounter in everyday life can damage these layers. “We assume that defective epithelial barriers play a role in triggering the onset of two billion chronic illnesses,” says Akdis. This connection is explained by the epithelial barrier hypothesis, which Akdis has helped develop during his more than 20 years of research in this field.

Toxic substances in rinse agents

The researchers used a newly developed technology for their study – human intestinal organoids and intestinal cells on microchips. The tissue forms a three-dimensional clump of cells that is very similar to the intestinal epithelium in humans. The team used various biomolecular methods to analyze the effect that commercial detergents and rinse aids have on these cells. They diluted these substances to reflect the amounts that would be present on dry dishes (1:10,000 to 1:40,000).

The result was that high doses of rinse agents killed the intestinal epithelial cells and lower doses made it more permeable. Researchers also observed the activation of several genes and cell signaling proteins that could trigger inflammatory responses. A more detailed analysis showed that one component of the rinse agent – alcohol ethoxylates – was responsible for this reaction.

According to Akdis, these findings have significant implications for public health. “The effect that we found could mark the beginning of the destruction of the gut’s epithelial layer and trigger the onset of many chronic diseases,” he says. Akdis calls for an immediate response: “It is important to inform the public about this risk since alcohol ethoxylates seem to be commonly used in commercial dishwashers.”

Reference: “Gut epithelial barrier damage caused by dishwasher detergents and rinse aids” by Ismail Ogulur, Yagiz Pat, Tamer Aydin, Duygu Yazici, Beate Rückert, Yaqi Peng, Juno Kim, Urszula Radzikowska, Patrick Westermann, Milena Sokolowska, Raja Dhir, Mubeccel Akdis, Kari Nadeau and Cezmi A. Akdis, 1 December 2022, Journal of Allergy and Clinical Immunology.
DOI: 10.1016/j.jaci.2022.10.020