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Plastic cutting boards are mostly just plain undyed polyethylene (HDPE)- which is just a fully saturated perfectly straight hydrocarbon, similar to saturated fa

by _yb2s 2y ago

Plastic cutting boards are mostly just plain undyed polyethylene (HDPE)- which is just a fully saturated perfectly straight hydrocarbon, similar to saturated fat or wax and lacks the kind of reactive functional groups that make other plastic polymers toxic. I think it is quite unlikely that HDPE in particular is toxic or endocrine disrupting to humans in the way a lot of other plastics seem to be. It's also basically just a very viscous fluid and I suspect would flow into grooves when a knife blade hits it, without releasing particles like harder more solid plastics would. Personally, I try to avoid having most plastics contact my food and water, but make an exception for HDPE. In general, each plastic polymer is very different from another chemically, and it makes sense to consider their safety independently, and not group all plastics together.

_DeadFred_ 2y ago
The problem is cutting boards break off little bits of plastic with use and your body has evolved zero mechanism for disposing of microplastics once they are in your system. https://www.ewg.org/news-insights/news/2023/10/making-meals-without-microplastics-tips-safer-cutting-boards https://www.ewg.org/news-insights/news/2023/10/making-meals-... https://phys.org/news/2024-12-microplastics-multiple-human-tissues-lesions.html https://phys.org/news/2024-12-microplastics-multiple-human-t...
- _yb2s 2y ago
  I've looked a bit, and not been able to find evidence of HDPE getting into cells, or exhibiting biological toxicity, whereas there seems to be quite a bit of evidence of this for almost every other type of plastic. Still, I wouldn't blame someone for just avoiding all plastic food contact by the precautionary principle. The first study you linked is interesting- it does seem to confirm what I suspected, that HDPE does flow on knife impact causing it to release less plastic debris than other plastics, but still not zero. The second one seems to be a fairly low quality review article looking at what does sound like a concerning issue, but doesn't really consider different types of plastic independently. It might be useful in the sense of citing a lot of papers in this area that could be looked at directly.
timr 2y ago
> Plastic cutting boards are mostly just plain undyed polyethylene (HDPE)- which is just a fully saturated perfectly straight hydrocarbon, similar to saturated fat or wax and lacks the kind of reactive functional groups that make other plastic polymers toxic. This is all just completely made up -- starting with the assertion that "plastic polymers" (whatever those are; you're not being specific enough to have a debatable claim) are "toxic" in the first place.
- _yb2s 2y ago
  Everything I said are basic facts about plastic chemistry you can verify yourself, but I can elaborate more if that is helpful. If you'd like a more specific example of what I am talking about, take for example Bisphenol A (BPA), one of the monomers used in making polycarbonate - which most people have heard of, and has now been eliminated from consumer products like water bottles (edited per correction from reply below). It is chemically similar enough to steroid hormones, that it can bind to steroid hormone receptors (in particular estrogen receptors), making it a potential endocrine disruptor. HDPE does not contain complex functional groups that are likely to mimic natural hormones and bind to receptors or enzyme active sites in a living system. In general, molecules that contain a lot of aromatic rings, or reactive functional groups are more likely to exhibit drug like effects or toxicity. Such properties are systematically enriched for in chemical libraries used for drug discovery, but if trying to avoid unintended biological effects, it makes sense to exhibit more caution with such molecules.
  - BadHumans 2y ago
    > take for example Bisphenol A (BPA), one of the monomers used in making polycarbonate - which most people have heard of, and has now been almost universally eliminated from things that contact food and water for human consumption. Why did they find large amounts of BPA in more than a few foods they tested if it has been eliminated from food manufacturing process?
    - _yb2s 2y ago
      Good point- what I said is wrong, it was removed from consumer goods like water bottles but is still legal and used in food manufacturing equipment in the USA. It has been banned in the EU from all food contact. I have edited my post above to correct this.
kleton 2y ago
Silicon dioxide is not chemically toxic. But you can put microfiber crystals of it in a mammal's lungs and get tumors that grow around them. It is not a huge stretch of the imagination from there to hypothesize that nano- and micro-particles of a nontoxic polymer could also cause problems.
- _yb2s 2y ago
  True- I don't think they are likely to specifically exhibit the drug like toxicity that some other plastics are responsible for, but you are right that doesn't rule out other potential issues from a small, hydrophobic, physical object. I'm not 100% sure HDPE is safe- and if not it might depend on how it is used, but I am less concerned about it than a lot of other plastics.
- wlesieutre 2y ago
  Since plastic vs wood cutting boards is what kicked this discussion off, I’d also point out fine wood particles will give you lung cancer too
bilsbie 2y ago
That’s a good point. Why do they say water bottles are so bad? Can’t they use something like hdpe?
- tomjakubowski 2y ago
  HDPE Nalgenes (branded "Ultralite") are my standard water bottle. Unlike the clear plastic sort, they're not see-through, nor very heat/impact resistant, but they weigh next to nothing. Just don't use 'em as a hot water bottle.
  - _yb2s 2y ago
    Same here, although they sadly discontinued the narrow mouth version.
  - dublinben 2y ago
    The soft HDPE bottles are actually more heat and impact resistant than the rigid clear polycarbonate ones. They’re the standard recommendation for winter hiking. https://momgoescamping.com/water-bottles-insulators-winter/ https://momgoescamping.com/water-bottles-insulators-winter/
- _yb2s 2y ago
  Honestly the water bottles are probably fine as they likely don’t leach much BPA unless something happens to break the polymer apart- like contact with a strong chemical solvent. Although BPA is an endocrine disruptor, it is likely that normal use of a polycarbonate water bottle is fine. They stopped selling them because people got afraid and stopped buying them. I still see no reason to use one given the uncertainty. You can get really good HDPE, stainless steel, and glass water bottles with a silicon impact cover.
  - dehrmann 2y ago
    There's an argument that polycarbonate is very well-studied and the BPA released is low, while some of the alternatives have unknown risks.

by _yb2s 2y ago

_DeadFred_ 2y ago

The problem is cutting boards break off little bits of plastic with use and your body has evolved zero mechanism for disposing of microplastics once they are in your system. https://www.ewg.org/news-insights/news/2023/10/making-meals-without-microplastics-tips-safer-cutting-boards https://www.ewg.org/news-insights/news/2023/10/making-meals-... https://phys.org/news/2024-12-microplastics-multiple-human-tissues-lesions.html https://phys.org/news/2024-12-microplastics-multiple-human-t...

_yb2s 2y ago
I've looked a bit, and not been able to find evidence of HDPE getting into cells, or exhibiting biological toxicity, whereas there seems to be quite a bit of evidence of this for almost every other type of plastic. Still, I wouldn't blame someone for just avoiding all plastic food contact by the precautionary principle. The first study you linked is interesting- it does seem to confirm what I suspected, that HDPE does flow on knife impact causing it to release less plastic debris than other plastics, but still not zero. The second one seems to be a fairly low quality review article looking at what does sound like a concerning issue, but doesn't really consider different types of plastic independently. It might be useful in the sense of citing a lot of papers in this area that could be looked at directly.

timr 2y ago

> Plastic cutting boards are mostly just plain undyed polyethylene (HDPE)- which is just a fully saturated perfectly straight hydrocarbon, similar to saturated fat or wax and lacks the kind of reactive functional groups that make other plastic polymers toxic. This is all just completely made up -- starting with the assertion that "plastic polymers" (whatever those are; you're not being specific enough to have a debatable claim) are "toxic" in the first place.

_yb2s 2y ago
Everything I said are basic facts about plastic chemistry you can verify yourself, but I can elaborate more if that is helpful. If you'd like a more specific example of what I am talking about, take for example Bisphenol A (BPA), one of the monomers used in making polycarbonate - which most people have heard of, and has now been eliminated from consumer products like water bottles (edited per correction from reply below). It is chemically similar enough to steroid hormones, that it can bind to steroid hormone receptors (in particular estrogen receptors), making it a potential endocrine disruptor. HDPE does not contain complex functional groups that are likely to mimic natural hormones and bind to receptors or enzyme active sites in a living system. In general, molecules that contain a lot of aromatic rings, or reactive functional groups are more likely to exhibit drug like effects or toxicity. Such properties are systematically enriched for in chemical libraries used for drug discovery, but if trying to avoid unintended biological effects, it makes sense to exhibit more caution with such molecules.
- BadHumans 2y ago
  > take for example Bisphenol A (BPA), one of the monomers used in making polycarbonate - which most people have heard of, and has now been almost universally eliminated from things that contact food and water for human consumption. Why did they find large amounts of BPA in more than a few foods they tested if it has been eliminated from food manufacturing process?
  - _yb2s 2y ago
    Good point- what I said is wrong, it was removed from consumer goods like water bottles but is still legal and used in food manufacturing equipment in the USA. It has been banned in the EU from all food contact. I have edited my post above to correct this.

kleton 2y ago

Silicon dioxide is not chemically toxic. But you can put microfiber crystals of it in a mammal's lungs and get tumors that grow around them. It is not a huge stretch of the imagination from there to hypothesize that nano- and micro-particles of a nontoxic polymer could also cause problems.

_yb2s 2y ago
True- I don't think they are likely to specifically exhibit the drug like toxicity that some other plastics are responsible for, but you are right that doesn't rule out other potential issues from a small, hydrophobic, physical object. I'm not 100% sure HDPE is safe- and if not it might depend on how it is used, but I am less concerned about it than a lot of other plastics.
wlesieutre 2y ago
Since plastic vs wood cutting boards is what kicked this discussion off, I’d also point out fine wood particles will give you lung cancer too

bilsbie 2y ago

That’s a good point. Why do they say water bottles are so bad? Can’t they use something like hdpe?

tomjakubowski 2y ago
HDPE Nalgenes (branded "Ultralite") are my standard water bottle. Unlike the clear plastic sort, they're not see-through, nor very heat/impact resistant, but they weigh next to nothing. Just don't use 'em as a hot water bottle.
- _yb2s 2y ago
  Same here, although they sadly discontinued the narrow mouth version.
- dublinben 2y ago
  The soft HDPE bottles are actually more heat and impact resistant than the rigid clear polycarbonate ones. They’re the standard recommendation for winter hiking. https://momgoescamping.com/water-bottles-insulators-winter/ https://momgoescamping.com/water-bottles-insulators-winter/
_yb2s 2y ago
Honestly the water bottles are probably fine as they likely don’t leach much BPA unless something happens to break the polymer apart- like contact with a strong chemical solvent. Although BPA is an endocrine disruptor, it is likely that normal use of a polycarbonate water bottle is fine. They stopped selling them because people got afraid and stopped buying them. I still see no reason to use one given the uncertainty. You can get really good HDPE, stainless steel, and glass water bottles with a silicon impact cover.
- dehrmann 2y ago
  There's an argument that polycarbonate is very well-studied and the BPA released is low, while some of the alternatives have unknown risks.