3 ms·

> Arsenic at 0.0025 mg/L That is well below the noise floor. Like the similarly toxic selenium, arsenic is an essential micronutrient in animal biology. It is

> Arsenic at 0.0025 mg/L That is well below the noise floor. Like the similarly toxic selenium, arsenic is an essential micronutrient in animal biology. It is possible to be deficient in arsenic, though rare in practice. Natural background levels are far higher in many locales with no adverse effects. I often see trace quantities of arsenic trotted out by the popular media for scaremongering purposes. Examples like the above are an immediate red flag.

nradov 5mo ago
Could you expand on what makes arsenic an essential micronutrient? What are the clinical signs and symptoms of severe arsenic deficiency? I've never heard of this before.
- selectodude 5mo ago
  It’s not hard to figure this stuff out yourself.
  - AnimalMuppet 5mo ago
    Perhaps not. At the same time, when a person makes a claim, and several (or several hundred) people read it, it seems more efficient to ask the person who made the claim to supply the documentation, rather than making the several (hundred) people all do the looking. The looking does not have to be hard for this to be true. Also, just in general debate terms, the one who makes a claim is the one who has the burden of substantiating it.
  - nradov 5mo ago
    It is hard. I did some searches before commenting and couldn't find anything about arsenic deficiency. I don't know much about arsenic biochemistry so could you kindly point us to a good source?
    - pegasus 5mo ago
      It's super easy with ChatGPT, for example. See my other reply in this thread, I've included the responses there.
- lazide 5mo ago
  It has no known physiological role in humans. Selenium has similar stuff going on. [https://en.wikipedia.org/wiki/Arsenic_biochemistry https://en.wikipedia.org/wiki/Arsenic_biochemistry]
- jandrewrogers 5mo ago
  IIRC, severe deficiency of arsenic leads to a type of wasting. The precise role is uncertain. Based on animal models the rough estimates for human requirements are similar to selenium. Humans get enough arsenic from water and other background sources that deficiency is virtually unknown. My understanding is that there was historical anecdotal evidence for rare arsenic deficiency from animal husbandry that caused it to be investigated. These days they systematically test for the trace micronutrient status of e.g. heavy metals by inducing extreme deficiency using mammal models. Most of the time nothing happens but it is difficult to eliminate the possibility of contamination creating a null signal. Probably the most surprising element for which they have suggestive evidence of biological necessity is lead.
  - nradov 5mo ago
    Could you give us some specific citations for evidence of biological necessity for arsenic and lead? I searched on PubMed but couldn't find anything.
    - jandrewrogers 5mo ago
      It is damn near impossible to search on Google for this literature today. Fortunately, some of the links have been posted to this site before, which is searchable. :) Here is the first good reference I could find, which surveys some of the other literature. It mentions lead in rat models. https://pmc.ncbi.nlm.nih.gov/articles/PMC2246629/ https://pmc.ncbi.nlm.nih.gov/articles/PMC2246629/
      - pegasus 5mo ago
        Since maybe half a year ago, the best way to search stuff like that, by a huge margin, are frontier models like ChatGPT or Gemini. Here's what they found, the TLDR is that lead is much less likely to be essential (in extremely minute amounts) than arsenic, which has been proven to be beneficial in trace amounts for a bunch of mammals. Since those experiments cannot be done on humans, we don't know if it is the same situation in our case, but the null hypothesis at this point is that it is. https://chatgpt.com/share/6a0d522f-5688-83eb-b80c-0f7b157faed5 https://chatgpt.com/share/6a0d522f-5688-83eb-b80c-0f7b157fae... https://gemini.google.com/share/e2e52489a41e https://gemini.google.com/share/e2e52489a41e

nradov 5mo ago

Could you expand on what makes arsenic an essential micronutrient? What are the clinical signs and symptoms of severe arsenic deficiency? I've never heard of this before.

selectodude 5mo ago
It’s not hard to figure this stuff out yourself.
- AnimalMuppet 5mo ago
  Perhaps not. At the same time, when a person makes a claim, and several (or several hundred) people read it, it seems more efficient to ask the person who made the claim to supply the documentation, rather than making the several (hundred) people all do the looking. The looking does not have to be hard for this to be true. Also, just in general debate terms, the one who makes a claim is the one who has the burden of substantiating it.
- nradov 5mo ago
  It is hard. I did some searches before commenting and couldn't find anything about arsenic deficiency. I don't know much about arsenic biochemistry so could you kindly point us to a good source?
  - pegasus 5mo ago
    It's super easy with ChatGPT, for example. See my other reply in this thread, I've included the responses there.
lazide 5mo ago
It has no known physiological role in humans. Selenium has similar stuff going on. [https://en.wikipedia.org/wiki/Arsenic_biochemistry https://en.wikipedia.org/wiki/Arsenic_biochemistry]
jandrewrogers 5mo ago
IIRC, severe deficiency of arsenic leads to a type of wasting. The precise role is uncertain. Based on animal models the rough estimates for human requirements are similar to selenium. Humans get enough arsenic from water and other background sources that deficiency is virtually unknown. My understanding is that there was historical anecdotal evidence for rare arsenic deficiency from animal husbandry that caused it to be investigated. These days they systematically test for the trace micronutrient status of e.g. heavy metals by inducing extreme deficiency using mammal models. Most of the time nothing happens but it is difficult to eliminate the possibility of contamination creating a null signal. Probably the most surprising element for which they have suggestive evidence of biological necessity is lead.
- nradov 5mo ago
  Could you give us some specific citations for evidence of biological necessity for arsenic and lead? I searched on PubMed but couldn't find anything.
  - jandrewrogers 5mo ago
    It is damn near impossible to search on Google for this literature today. Fortunately, some of the links have been posted to this site before, which is searchable. :) Here is the first good reference I could find, which surveys some of the other literature. It mentions lead in rat models. https://pmc.ncbi.nlm.nih.gov/articles/PMC2246629/ https://pmc.ncbi.nlm.nih.gov/articles/PMC2246629/
    - pegasus 5mo ago
      Since maybe half a year ago, the best way to search stuff like that, by a huge margin, are frontier models like ChatGPT or Gemini. Here's what they found, the TLDR is that lead is much less likely to be essential (in extremely minute amounts) than arsenic, which has been proven to be beneficial in trace amounts for a bunch of mammals. Since those experiments cannot be done on humans, we don't know if it is the same situation in our case, but the null hypothesis at this point is that it is. https://chatgpt.com/share/6a0d522f-5688-83eb-b80c-0f7b157faed5 https://chatgpt.com/share/6a0d522f-5688-83eb-b80c-0f7b157fae... https://gemini.google.com/share/e2e52489a41e https://gemini.google.com/share/e2e52489a41e