Dishwashers used by professionals leave rinse aid residue, which damages the protective layer of the intestine, on cutlery after cleaning, according to a Swiss study.
- The intestinal epithelial barrier is the layer of cells that lines the intestinal tract and controls what enters the body.
- A disruption of this barrier is associated with food allergies, gastritis, diabetes, obesity, cirrhosis of the liver, rheumatoid arthritis, multiple sclerosis, autism, chronic depression and Alzheimer’s disease.
Restaurants, school canteens, barracks… In these different establishments, there are professional dishwashers. These machines can clean, rinse and dry a large volume of plates, glasses and cutlery in a few minutes. Problem: the use of these household appliances used by professionals is not without risks for our intestinal health. This was revealed by researchers from the Swiss Institute for Allergy and Asthma Research, which is associated with the University of Zurich.
“Potentially toxic substances remain on the dishes”
To reach this conclusion, they carried out a study published in the journal The Journal of Allergy and Clinical Immunology. “The increased prevalence of many chronic inflammatory diseases linked to leaky gut epithelial barrier prompted us to investigate the role of heavy use of dishwasher detergents,” wrote the scientists.
They recalled that a typical cycle for a commercial dishwasher involves circulating hot water and detergent for about 60 seconds at high pressure. Then there is supposed to be a second 60 second wash and dry cycle where water and rinse aid are applied. “What is particularly alarming is that in many appliances there is no additional wash cycle to remove the remaining rinse aid. This means that potentially toxic substances remain on the dishes, where they dry then on the spot, explained Cezmi A. Akdis, author of the research and professor of allergology and immunology, in a statement.
Gut Health: Alcohol Ethoxylate Triggers Inflammatory Responses
As part of this work, the authors used a recently developed technology: human intestinal organoids and intestinal cells on microchips. The tissue forms a cluster of cells that resembles the intestinal epithelium in humans. The team used various biomolecular methods to analyze the effect of detergents and rinse aids on these cells. They diluted these substances to reflect the amounts that would be present on clean, dry dishes.
According to the results, dishwashers were not rinsing cutlery properly and leaving chemical residue on clean plates. In detail, high doses of rinse aids killed intestinal epithelial cells and lower doses made them more permeable. The team also observed the activation of several genes and proteins likely to trigger inflammatory responses. According to their more detailed analysis, alcohol ethoxylate, a component of rinse aids, was responsible for this reaction.
“We suspect that defective epithelial barriers play a role in triggering two billion chronic diseases. It is important to inform the general public of this risk, because alcohol ethoxylate seems to be very present in products used for commercial dishwashers, concluded Cezmi A. Akdis.