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Even with the best intentions of maintaining a healthy gut, the gut lining can still be compromised by what we eat. However, it is not only the food ingredients themselves, but also what we choose to use as plates, glasses and utensils to eat with. In a 2023 study published by The Journal of Allergy and Clinical Immunology (JACI), researchers found that our gut health can be negatively impacted through dishwasher detergents and rinse aids. When detergent residue remains on dishes, it can be disruptive to the intestinal epithelium barrier. Despite eating a gut healthy diet, the negative effects caused by dishwasher detergent and rinse aids can still impair your gut lining.

“…prevent the entry of harmful bacterial components and toxins…and at the same time effectively absorb nutrients…”

Our gut lining is composed of cells tightly packed together creating a wall, formerly known as the intestinal epithelium. This barrier acts as a protective wall to microbes and harmful food components out of the bloodstream. It is controlled by molecules called intercellular tight junction proteins which are tightly regulated. Not only does this epithelial “wall” help to protect our gut-based immune cells from bacterial influences, but it is also responsible for the absorption of nutrients. A healthy gut lining will be able to prevent the entry of harmful bacterial components and toxins by forming a strong protective barrier, and at the same time effectively absorb nutrients by the epithelial cells.

However, when these cells become damaged or the tight junctions become loose, gaps will form within the wall. When these gaps form, it compromises the integrity of the intestinal epithelial barrier, causing activation of the gut-based immune system and allowing inflammatory signals and harmful molecules to enter the bloodstream. This increased intestinal permeability is commonly referred to in the lay press as leaky gut, a situation that has been implicated as a key factors in many chronic diseases.

Increased intestinal permeability is caused by many factors, but our diet plays a major role in ensuring that we fortify our gut lining. It is essential to include foods in the diet such as high fiber and probiotic rich foods that promote a healthy gut microbiome, strengthen the intestinal barrier and stimulate the microbial production of anti-inflammatory molecules, such as butyrate. Everything we eat or drink will directly impact our gut lining and intestinal permeability, so it is critical to be intentional with our dietary choices. Based on the results of this study, even being intentional with the cleaning products being used to wash our dishware is also a critical component to maintaining our gut health.

In the study, “Gut epithelial barrier damage caused by dishwasher detergents and rinse aids,” it becomes apparent that the cleaning products we choose to use on the utensils and dishes that we eat with, can have significant negative effects on our gut and body. The researchers evaluated the health hazard that exposure to dishwasher detergents and rinse aids, commonly used both in the household and for commercial use, can specifically have on the intestinal epithelium barrier.

“it becomes apparent that the cleaning products we choose to use on the utensils and dishes that we eat with, can cause significant damage to our body.”

In the study, the investigators used professional grade dishwashers. These professional dishwashers are popularly used in restaurants, hotels, hospitals, schools, and other public food consumption cafeterias. They possess the power to ensure that the dishware is thoroughly sanitized at a very fast rate, typically taking under two minutes. While the dishes are fully sanitized in this short amount of time, they do not have a second rinse following the initial cycle. This means that the rinse aid being used is more likely to remain on the utensils or dishes that are being washed.

The researchers had hypothesized that if the residue from the detergent and rinse aid is not being fully removed from the commercial dishwashers, then once they are dry, the residue would remain on the surface of the dishware and later be ingested when using the dishware to eat. The problem with leftover dishwasher residue is that it contains several potentially harmful and toxic substances, and the impact that these substances may have on gut health are not yet fully understood.

After analyzing the amount of residue remaining on the dishware after a wash cycle in a professional dishwasher, the researchers found evidence for damage being caused to the tight junctions and epithelial cells in the gut. The observed detergent toxicity was attributed to exposure to rinse aid up to 1:20,000 dilutions. This means that taking only 1 ml of the rinse aid and diluting it to 1/20 four times would still be enough to cause damage to the cells. When individual ingredients were examined closely, they found one ingredient, alcohol ethoxylates, had a particular negative effect on the epithelial barrier. The specific ingredient is commonly found in many household and commercial dishwasher detergents worldwide.

“The specific ingredient that was found to cause the damage was alcohol ethoxylates, commonly found in many household and commercial dishwasher detergents worldwide.”

It is important to emphasize that this study used professional grade dishwashers and not household dishwashers. Household dishwashers tend to have longer cycles and rinse times. The effect of how much residue remains following a dish washing cycle performed by a household dishwasher compared to a commercial dishwasher would vary based on the differences in their cycle lengths and power. Nonetheless, many commonly used household rinse aids still contain alcohol ethoxylates as an ingredient, which could cause damage if it is not fully rinsed off.

Furthermore, the dishwashers being used in areas of public food consumption were shown to leave damaging levels of residue from rinse aids containing alcohol ethoxylates. These dishwashers are the ones being used in places such as schools and hospitals. If a child is eating from their school cafeteria every day, they may be exposed to high levels of the detergent residue that become harmful to their gut health, causing an inflammatory response. This would in turn put these children at risk of developing some of the chronic diseases which make up our chronic noncontagious disease epidemic, such as obesity, metabolic disorders and inflammatory bowel diseases. The prevalence of these disorders has been increasing in younger and younger age groups.

“If a child is eating from their school cafeteria every day, they may be exposed to high levels of the detergent residue that become harmful to their gut health, causing an inflammatory response.”

If confirmed, the results of this study have significant implications for public health. The damage caused to the epithelial barrier with secondary activation of the gut-based immune system and alterations in metabolism linked to the dishwasher detergents and rinse aids being used may be an important risk factor in the development of many chronic diseases and prevention by banning some of the offending chemicals is an important step towards this goal.