Are Dishwashers Toxic? Uncovering the Hidden Health Risks of Everyday Use

Dishwashers are a common convenience in both homes and commercial kitchens, making cleaning dishes faster and easier. However, recent research has raised concerns about potential health risks associated with dishwasher use, particularly with commercial models. This article explores these risks, discusses whether they extend to household dishwashers, and separates theory from reality.

The Toxicity Question: What Chemicals Are Involved?

Dishwasher detergents and rinse agents, whether used in commercial or household models, contain chemicals designed to clean and sanitize dishes. These include phosphates, chlorine, and alcohol ethoxylates, which help remove grease and grime quickly. While effective for cleaning, they may pose health risks if residues remain on dishes.

Commercial dishwashers—typically used in restaurants and large-scale kitchens—operate with short, high-temperature cycles:

1. Detergent Wash: A high-pressure, hot water wash that uses detergent to clean dishes quickly.
2. Rinse Cycle: This applies a rinse agent that helps dishes dry faster.

A recent study from the Swiss Institute of Allergy and Asthma Research (SIAF) linked with the University of Zurich (UZH) highlighted that many commercial dishwashers do not include an additional rinse cycle. This can leave residues, particularly from alcohol ethoxylates, on dishes. The study’s findings suggest that when ingested over time, these residues could damage the gut lining, leading to inflammation and potentially increasing the risk of chronic diseases.

Are Household Dishwashers Safer?

Household dishwashers, designed for longer cycles and more thorough rinsing, generally reduce the amount of residue left on dishes compared to commercial models. However, this does not mean they are entirely without risk:

1. Chemical Residue: Even in household dishwashers, traces of detergent and rinse agents may remain, especially when using products with strong cleaning agents like phosphates.
2. Microbial Contamination: Both types of dishwashers create warm, moist environments that can harbor bacteria and fungi, such as E. coli and Candida. Regular cleaning is necessary to prevent dishes from becoming contaminated.
3. Plastic Leaching: Washing plastic items at high temperatures—common in both commercial and household settings—can cause chemicals like bisphenol A (BPA) to leach into food.
4. Airborne Chemicals: The drying phase of dishwashers may release volatile organic compounds (VOCs). Long-term exposure to these compounds could potentially affect respiratory health.

Is There Evidence of Actual Health Issues?

While the theoretical risks presented by the study sound concerning, it is crucial to approach the findings with a balanced perspective:

• Laboratory Findings vs. Real-World Evidence: The study conducted by the Swiss team used high concentrations of chemicals to observe effects on gut cells in lab conditions. These findings provide a plausible mechanism for how damage could occur, but they do not prove that these effects happen in everyday situations where exposure levels are far lower.
• No Documented Cases—Yet: To date, there are no recorded instances of gut issues or chronic diseases directly linked to eating from dishes washed in commercial dishwashers. However, it is important to recognize that just because such cases have not been documented does not mean they do not exist. Since this issue has not been previously recognized, it is possible that the connection has been overlooked. More research is needed to explore whether there is a higher association between toxic chemicals and gut health than currently understood—or if the risk remains minimal.
• The Need for More Research: Given the potential for both outcomes, more comprehensive studies in real-life conditions are necessary to determine the true extent of any risks. These studies could help identify whether there is a significant health impact or if the current use of dishwashers remains safe.

Reducing Risk: Practical Tips for Safe Dishwasher Use

Whether you encounter commercial or household dishwashers, there are practical steps you can take to minimize health risks:

• Choose Eco-Friendly Detergents: Products with fewer harsh chemicals are less likely to leave harmful residues.
• Run an Extra Rinse Cycle: If possible, adding an extra rinse phase can help wash away residual chemicals.
• Clean the Dishwasher Regularly: Keeping the dishwasher clean can prevent microbial buildup that could contaminate dishes.
• Avoid Washing Plastic Items: Hand washing plastic dishes can reduce exposure to chemicals like BPA, especially at high temperatures.

Conclusion

While the study from the Swiss Institute suggests potential risks from dishwasher chemicals, it’s important to balance this with the reality that current evidence is limited and preliminary. It is possible that the risks are higher than currently understood, but it is also possible that these risks remain minimal. More research is needed to explore these possibilities thoroughly. For now, both commercial and household dishwashers offer a generally safe way to clean dishes, as long as they are used and maintained properly. By taking simple precautions, you can continue to enjoy their convenience without unnecessary worry.

References

• Akdis, C.A., et al. “Gut epithelial barrier damage caused by dishwasher detergents and rinse aids.” The Journal of Allergy and Clinical Immunology 2023 Feb;151(2):469-484 doi: 10.1016/j.jaci.2022.10.020.
• Shavit, J. “Researchers find a surprising link between dishwashers and chronic illnesses.” The Brighter Side of News.