Gut epithelial barrier damage caused by dishwasher detergents and rinse aids

[r1ch]

From my understanding, this article is only about professional dishwashers used in restaurants and hotels etc. that use much higher concentrations and less rinsing than consumer dishwashers. They specifically mention that they could not repeat their findings on consumer dishwashers.

[sschueller]

Yes but isn't this even worse? I can control what I use at home. I can't when I eat or drink out.

So I get to pick between PFAS soaked throwaway single use cardboard cups or epithelial barrier damaging glass/ceramic ware.

[mikkom]

> They specifically mention that they could not repeat their findings on consumer dishwashers.

this should be the top comment

[0x00_NULL]

This is not correct. It is about all dishwashers, but professional ones seem to lack a cleansing cycle after rinse aid is applied, thus the concentration of resulting rinse aid is higher. A consumer dishwasher is also used in their tests, but the concentration was much less than the professional dishwasher - however, they tested with 20g of rinse aid and used assumptions of the number and volume of washing cycles from their test dishwasher. A deviation of 10% difference in since water could increase the concentration significantly, by a factor of ~2 or more depending on the final rinsing stage.

So, in their example, the results in consumer dishwashers fell in the 1:40,000 - 1:80,000 dilution range. But, that does not necessarily apply to a different brand of dishwasher with a different method of rinsing. A 10% savings in the rinse cycle water might move that ratio into the 1:20,000 - 1:40,000 range (which is within the range of having an significant effect). So, I interpret this as not dismissing of consumer dishwashers, but rather indicating more careful study is needed.

[brundolf]

Every once in a while I grab a water cup, usually at a coffee shop, and I notice the cups smell a bit like bleach. Always struck me as weird, but I figured they wouldn't put them out that way if it wasn't safe

I might be more careful now

[the-dude]

I had over 10 years of eczeme/sensitivity between my fingers after operating a professional dishwasher for under a year.

I always thought the reason was the handling of the hot, sprayed tableware. It set on pretty quickly too : couple of months.

[chiefalchemist]

> When individual components of the rinse aid were investigated separately, alcohol ethoxylates elicited a strong toxic and barrier-damaging effect.

To clarify a bit, it's not professional dishwashers (the machines) but the soap / chemicals used for commercial dishwashing. Minor but important when thinking about the broader problem.

Mind you, it gets diluted but those end up in the water supply, as does many other knows and unknowns. For me, the question has not be what effect does Compound X or Compound Y have individually, but when in the wild what happens when you combine A to Z+? Then what?

[LargoLasskhyfv]

Did you do the 'sniff-test'? I did, and do again from time to time, when elsewhere. In my experience I can smell that stuff on the dishes and glassware, even after having cleaned them by hand before, and even after a second run without detergent. On every consumer dishwasher, so far.

That alone was reason for me to avoid them, since decades. And this hasn't changed. And I have no 'super-nose'(I think).

[Turing_Machine]

I knew a guy who had an ugly, painful ulcer on the top of his foot for a few months after dripping some liquid commercial dishwasher detergent on his sneaker while refilling the dispenser.

That stuff is nasty.

[nottorp]

Another interesting question is what countries they got their detergents from. Formulas may vary across the world based on what's allowed and what's not.

[z7]

Correct, but the question remains if the lower concentrations in consumer dishwashers might also affect health on some level.

[TedDoesntTalk]

I don’t see any mention of that in the article. Where did you read it?

[m463]

Most residential dishwashers seem to have a rinse-aid dispenser that you fill up with usually finish jet-dry.

It seems to have the alcohol ethoxylates mentioned in this paper:

https://www.ewg.org/guides/cleaners/2994-FinishJetDryRinseAg...

I expect it is also in the finish dishwasher detergent pods.

digging deeper the wikipedia article on ethoxylation says:

Ethoxylated fatty alcohols are often converted to the corresponding organosulfates, which can be easily deprotonated to give anionic surfactants such as sodium laureth sulfate.

https://en.wikipedia.org/wiki/Ethoxylation

I had trouble with SLS (sodium lauryl sulfate) and switched to toothpaste, shampoo and laundry detergents without this.

This chemical has gotten a bad rap and a lot of formulas were changed to use sodium laureth sulfate mentioned above. (I avoided that too)

I'll bet they are all trouble.

[danw1979]

Get yourself a big old tub of anhydrous citric acid from Amazon or wherever, make up a 10% solution and use that in place of rinse aid. Just check with your dishwasher manufacturer that it’s not going to cause issues first.

I got a new Miele unit a few months ago and the manual specifically advises the use of such a solution, with caution not to make it any stronger.

It’s been working like a charm.

[jasongill]

From my experience, this will eventually remove any printed on markings from your glassware; for example, all of the measuring lines on Pyrex cups, etc.

Not a huge deal, just worth noting

[heftig]

Does it have to be anhydrous? Seems like a waste to go for the more expensive stuff when you're going to dissolve it anyway. Food-grade citric acid monohydrate should be cheaper.

[walthamstow]

I'm not using rinse aid at all. Just dishwasher gel with no rinse aid included, and salt. Cheap-ish Beko dishwasher. No issues.

[mathgeek]

What are the advantages over plain vinegar? Been using that my whole life without any concern beyond wanting to avoid expensive rinse aids.

[cubefox]

According to this review, citric acid doesn't work as a rinse aid replacement:

https://www.test.de/Klarspueler-im-Test-Jeder-dritte-hinterl...

[ipqk]

I stopped using rinse-aid entirely on my 10-year old Bosch, and barely notice a difference. Maybe plastics come out a tad wetter than before, but they were never fully dry even with rinse-aid.

[derwiki]

The last time an article like this went around, I decided to do the same thing with my Miele. The metal starting becoming stained pretty soon, and just recently I decided to switch to 7th Generation organic detergent powder. YMMV but wanted to share my anecdata for anyone considering the same.

[maayank]

Doing the same for rinse aid. Didn’t find a practical alternative for the main cleaning solution.

[garblegarble]

I've found rinse aids that include citric acid end up pitting stainless steel cutlery over time, so I avoid them

[the-dude]

(2022)

1 year ago, 411 comments : https://news.ycombinator.com/item?id=33822149

Got triggered by epithelial.

[sergioisidoro]

Ok, this is posed to generate some sensationalist headlines. Do we get these concentrations with regular use in a dishwasher? Does it have cumulative exposure effects? Does it even reach the gut lining after digestion enzymes and acids?

From the summary it seems that they only investigated the dose dependent toxicity.

[rafaelferreira]

The summary says "detergent residue from professional dishwashers demonstrated the remnant of a significant amount of cytotoxic and epithelial barrier–damaging rinse aid remaining on washed and ready-to-use dishware", which might address the question about concentrations in regular use.

[pierat]

You can say that, but a lot of detergents and rinse aids use the class of nasty chemicals. But there's detergents and rinse aids that don't have it.

What you're looking for is "Alcohol ethoxylates". Avoid these.

[instagib]

https://news.ycombinator.com/item?id=33822149

11 months ago. Direct copy of linked study.

I stopped using extra shine mode on my Bosch dishwasher to save a little rinse aid. Noticed no difference. Vinegar ruined the seals and had to replace it.

[vjk800]

Can someone who understands more about chemistry tell me where exactly which detergents use alcohol ethoxylates and how do I spot them from the label? Should I be concerned about this at home?

[dellamorta]

Household dishwashers are not affected because they usually have an additional wash cycle in the end. This study is about professional machines which wash dishes in mere minutes. So you can't do anything about it if you still want to eat at restaurants and don't want to bring your own dishes.

[cubefox]

There is a detailed article in German with more information:

https://www.spektrum.de/news/klarspueler-gefahr-fuer-die-dar...

Overall, this sounds like the danger is rather low.

[mancerayder]

Anyone noticed how they wash and rinse behind bars? It can be terrifying. The ones that don't use industrial dishwashers (bad as we're learning here) also just do a rapid sub 1 second dip into one sink with detergent chemicals, a sub 1 second dip onto a second water sink, and then upside down it goes on the shelf, ready to be reused.

How naive was I to think it's both cleaning well and not leaving dangerous chemicals as residue to mix onto a water or beer.

[konamicode]

I might be generalising but in some countries (UK) it's common to not rinse soap/washing up liquid off dishes after washing them by hand. Being hypochondriac I was always curious about health aspects of this and feared something similar to what's described in the article.

[jwells89]

I’m surprised that people don’t taste that in the food/drink they consume off their soapy dishes. It’s a distinct unpleasant taste that I tend to over rinse somewhat just to avoid, especially with cups/mugs where transfer is maximized.

[cubefox]

Though rinse aid is for mechanical dishwashers only.

[londons_explore]

I really want safety tests for consumer products to not be black/white.

Instead, more and more tests should be necessary for the more people you want to sell your product to, and the more people use it.

Some toy you sell 1000 of to people at a craft fayre should require a simple declaration that you didn't knowingly use leaded paint, while something you sell 10 billion of (eg dishwasher tablets) should require a whole independent team of scientists to do every study they can think of the establish risk/benefit.

[Sverigevader]

Interesting! I bought metal straws a while back for use at home, and I used to clean them in the dishwasher. After a while I realized that my stomach acted up almost every time I used them (regular aspartame sweetened sodas). It stopped when I started washing them by hand. My theory: There was detergent or rinse aid left inside. About as unscientific as you can get but I'm "certain"...

[raphlinus]

If you want to understand rinse aids better, I recommend this Technology Connections video (I've set the time stamp to the rinse aid section): https://www.youtube.com/watch?v=Ll6-eGDpimU&t=1935s

[wsgeorge]

Off topic: this is my first time hearing of rinse aids. It really feels odd (to me) that such a thing would exist. I thought we all just used water and a napkin.

I also have no experience with dishwashers, so how different is dishwater detergent from regular dishwashing soap?

[beowulfey]

Rinse aid is a dishwasher-specific product. It “helps” by removing residual soap and water spots from a dishwasher cycle.

I use a brand of dishwasher tabs that are supposed to be more “natural” and never use rinse aid, to no ill effect. Personally I think the normal tablets and rinse aid are specifically designed to be used together.

[dghughes]

I thought the study meant the stuff used at the end after washing. Here in Canada bars and restaurants after washing dishes must rinse dishes in a disinfectant bath and let the dishes air dry. The rinse aid sounds like something in the soap itself that helps the soap not stick to the final clean dishes.

It also seems to be the water used about 4 liters of water in commercial dishwashers vs 12 liters for household types. Commercial use less water, more powerful detergent, no water rinse.

[SAI_Peregrinus]

Rinse aid is a detergent that helps remove the residue other detergents or minerals in the water might leave on dishes after washing. It's not needed for hand washing, where mechanical scrubbing & a rinse with clean water performs the same task.

Dishwasher detergent is a surfactant, but is not a soap. All soaps are detergents, not all detergents are soaps. Soaps form insoluble precipitates when used with "hard" water, dishwasher detergents don't do that. They're not good to touch directly (rather harsh on the skin, they'll remove all the oil) but since they don't form those precipitates they work in a wider variety of conditions than soaps do. They also tend to include some other components, like bleach. That helps them clean better without needing mechanical scrubbing, which dishwashers don't do.

[dgudkov]

From the article:

>An exciting finding of the present study is that alcohol ethoxylates that are responsible for these toxic effects can be extracted from recently washed dishware and still kept the toxicity.

Scientists.

[jongjong]

Interesting, my mother taught me to always rinse the soap off from my dishes thoroughly and look at that. Sometimes superstition is more useful than expert advice.

[poizan42]

What's superstitious about that? Soap isn't made for human consumption, it seems prudent to avoid consumption unless proven safe.

[VyseofArcadia]

I wonder if this, combined with the fact that eating out has gotten significantly more common, is a factor in rising colon cancer rates.

[peterpost2]

I wonder if putting the dishwasher in soft water mode will also reduce the risk of this. Should use less rinse aid then.

[perlgeek]

Doesn't the software/hard water mode just affect how much the ion exchanger (filled with salt) is used?

[sizzle]

How effective would vinegar and the hottest water cycle be vs these gut destroying detergents?

[londons_explore]

Anyone who has touched an unwrapped dishwasher tablet with wet hands can tell you it has stuff in to pretty rapidly dissolve human...

[causi]

Horrible title, since the study didn't actually link normal detergent to gut damage, just rinse aid.

[pattmayne]

The offending ingredient (alcohol ephoxylate) is present in both my dishwasher pods and my rinse aid.

I might start skipping the rinse aid and I'll seek out dishwasher pods that don't have that ingredient.

But apparently it's more od an issue with "professional" (restaurant) dishwashers, which use less water and more chemicals. I gathered this from other comments and I don't know if it's true.

[eejjjj82]

> Enterocytic liquid-liquid interfaces were established on permeable supports, and direct cellular cytotoxicity, transepithelial electrical resistance, paracellular flux, immunofluorescence staining, RNA-sequencing transcriptome, and targeted proteomics were performed.

tldr; they did science

[stackzero]

Is there an ELI5?

[pattmayne]

Alcohol ephoxylate, which is present in rinse aid and some dishwasher pods,damages gut tissue and causes inflammatory and immune issues.

The study looked at concentrations found in "professional" (restaurant) doses of the chemicals.

I'm not sure how much it applies to residential dishwashers. I did find that ingredient in my rinse aid and dishwasher pods.

[jacobwilliamroy]

The stuff restaurants use to wash dishes is really bad for your tummy and very often that stuff is still on the dishes, while you're eating off of them.

[refurb]

Scientists create a layer of intestinal epithelial cells in a lab, minus all the other components in your intestine, then expose them to high concentrations of detergent and rinse aid.

Turns out cells don’t like it.

Who’d a thunk it?