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I didn't realize this until recently, but we don't actually know every chemical compound that's in our blood. As in, I don't believe there has been a study that

I didn't realize this until recently, but we don't actually know every chemical compound that's in our blood. As in, I don't believe there has been a study that takes 1 liter of blood and just documents every chemical structure found (at any concentration). Realizing that + learning about the seemingly vast gut microbiome has definitely led me to feel more humbled about what we know and can predict about human biology. I now think it's possible (but certainly not proven) that some hard to anticipate cascade of compounds (produced by gut, or foods, or environmental, or whatever) could be responsible for significantly increasing subjective feelings of hunger across the population at large, and this could lead to more calories being eaten than needed. I'm actually optimistic that this has happened, because then there might be an effective way to reverse the health problems we see... much like removing leaded gasoline seems to have helped reduce crime rates.

tamaharbor 4y ago
Why is it scientists would have us believe that they know everything definitively regarding covid, covid vaccines, climate change, etc?
- pc86 4y ago
  Literally no scientist has ever said that they know everything definitively about any topic, let alone those.
  - coding123 4y ago
    But we ascribe policy as if they do know 100%.
    - pc86 4y ago
      The fact that politicians are idiots, in addition to surprising approximately zero people, shouldn't be used to impugn science.
    - Spivak 4y ago
      I think there's a difference between "we make and adjust policy based on the strongest theory we have with an extra dose of caution" and "we think science is infallible."
- darkteflon 4y ago
  Go over to the Atlantic (https://www.theatlantic.com https://www.theatlantic.com) and read through their coronavirus coverage starting all the way back at the beginning of 2020. You have been sold a lie in your TikTok bubble.
netizen-936824 4y ago
The complexity of life is nuts. Once you start learning about how things work, you can see that we only know a tiny fraction of what's going on
- zionic 4y ago
  I mean sure, I’d love a scalpel but right now we don’t even have a hammer. It would be fantastic to do something even as simple as shut off the hunger signal for set intervals. Imagine if you literally couldn’t feel hunger from say… 10am to 6pm. There’s all sorts of cool hacks we do to improve humanity if we could get a grip on cravings.
- eastbound 4y ago
  Organic growth is like “Throw bits into the computer and see whether they make NPM.” …And the complexity of an NPM project is nuts, actually.
throwaway1777 4y ago
Highly doubt there is a silver bullet. There are likely a myriad of reasons because diets and genetics are so diverse. Sugar is the obvious villain though.
r3trohack3r 4y ago
Have you come across the environmental theory of obesity? https://slimemoldtimemold.com/2021/11/23/a-chemical-hunger-part-x-what-to-do-about-it/ https://slimemoldtimemold.com/2021/11/23/a-chemical-hunger-p...
adamrezich 4y ago
there is this sort of modern attitude toward science that tacitly assumes that we understand some sufficient majority of the nature of reality, when in fact reality is apparently infinitely fractal.
- throwaway4aday 4y ago
  I think most of the gaps in our understanding of biology stem from the scale at which we exist. Most biology takes place at the cellular or even the molecular level, we only see the very far removed macro-scale effects of a myriad of intertwined processes.
- mirceal 4y ago
  hah. not even close. we had moderate success in understanding and modeling some phenomena, but in the grand scheme of things we don’t know much. which is both scary and great if you have a curios mind
mirceal 4y ago
not only that, but our gut is literally the 2nd brain of our bodies. Read somewhere that there are more than 200 million in our gut. To put it in perspective, that’s more neurons that all the neurons in a dog’s brain.
layer8 4y ago
> a study that takes 1 liter of blood and just documents every chemical structure found (at any concentration) That’s because we don’t actually have the technology to do that. You can test for specific compounds that you know how to test for, and if their concentration is high enough. But there’s currently no way to e.g. go through a given sample molecule by molecule.
- DantesKite 4y ago
  Both these comments are a great way of putting it. I never thought about this before. Very interesting.
- daanlo 4y ago
  I thought you would be able to do this with a mass spectrometer. Although you would probably need a lot of blood :)
  - gxt 4y ago
    Exactly, IBM can make movies using individual atoms, surely we aren't too far from being able to look at molecular structures and deduce what compounds are in a sample of blood.
  - heavyset_go 4y ago
    You'd typically need reference samples if you're trying to get a typical lab to analyze compounds via mass spectrometry, which would make identification of unknown substances in blood hard for non-researchers.
  - montecarl 4y ago
    A mass spectrometer by itself, will tell you the mass to charge ratio of ions in a sample. In most samples the molecules themselves are not ions naturally and need to be ionized. This can be done using a number of techniques, but a common one is electron impact ionization, where electrons are slammed into molecules causing them to fragment into charged ions. This smashes the molecules up into small charged chunks which can then be analyzed by the mass spec. These mass spectra are good fingerprints for the original molecule and can be mapped back to what molecule must have been smashed to produced them. However, if you try to analyze the mass spectrum of a mixture of molecules that are similar you will not be able to deconvolute the result into any unique answer, i.e. there will be many possible mixtures of molecules that could have resulted in the mass spectrum. This limitation of mass spectrometry can be overcome by first separating out the mixture of molecules you want to analyze into different fractions before they are ionized and enter the mass spectrometer. One common way to do this is to use a gas chromatography column. This works by first heating the sample so that it turns into a gas, and then passing it through a long column that is packed with a material that will interact with the gas and slow some molecules more than others. Often it is packed with silica. In this way you get the technique called GC-MS (gas chromatography/mass spectrometry). GC-MS is a fantastic technique for analyzing complex mixtures but it will have its limits if there are too many different types of molecules in the mixture. In blood there will be tiny molecules like O2 and CO2 and giant macro-molecules like DNA. There is no technique I know of that can analyze such a wide range of molecular masses in one go. Plus mass spectrometry doesn't directly give you the structure just the masses of the fragments after you blow up the molecules (or the total mass if a more gentle ionization technique is used as is sometimes done for macromolecules). I write all this just to explain how there aren't any analytical instruments that you just inject a sample into and out pops all the chemicals and their concentrations. Blood is a amazing soup of different elements and molecules and a full analysis requires a large number of steps and different analytical techniques to get even close to fully characterizing.

tamaharbor 4y ago

Why is it scientists would have us believe that they know everything definitively regarding covid, covid vaccines, climate change, etc?

pc86 4y ago
Literally no scientist has ever said that they know everything definitively about any topic, let alone those.
- coding123 4y ago
  But we ascribe policy as if they do know 100%.
  - pc86 4y ago
    The fact that politicians are idiots, in addition to surprising approximately zero people, shouldn't be used to impugn science.
  - Spivak 4y ago
    I think there's a difference between "we make and adjust policy based on the strongest theory we have with an extra dose of caution" and "we think science is infallible."
darkteflon 4y ago
Go over to the Atlantic (https://www.theatlantic.com https://www.theatlantic.com) and read through their coronavirus coverage starting all the way back at the beginning of 2020. You have been sold a lie in your TikTok bubble.

netizen-936824 4y ago

The complexity of life is nuts. Once you start learning about how things work, you can see that we only know a tiny fraction of what's going on

zionic 4y ago
I mean sure, I’d love a scalpel but right now we don’t even have a hammer. It would be fantastic to do something even as simple as shut off the hunger signal for set intervals. Imagine if you literally couldn’t feel hunger from say… 10am to 6pm. There’s all sorts of cool hacks we do to improve humanity if we could get a grip on cravings.
eastbound 4y ago
Organic growth is like “Throw bits into the computer and see whether they make NPM.” …And the complexity of an NPM project is nuts, actually.

throwaway1777 4y ago

Highly doubt there is a silver bullet. There are likely a myriad of reasons because diets and genetics are so diverse. Sugar is the obvious villain though.

r3trohack3r 4y ago

Have you come across the environmental theory of obesity? https://slimemoldtimemold.com/2021/11/23/a-chemical-hunger-part-x-what-to-do-about-it/ https://slimemoldtimemold.com/2021/11/23/a-chemical-hunger-p...

adamrezich 4y ago

there is this sort of modern attitude toward science that tacitly assumes that we understand some sufficient majority of the nature of reality, when in fact reality is apparently infinitely fractal.

throwaway4aday 4y ago
I think most of the gaps in our understanding of biology stem from the scale at which we exist. Most biology takes place at the cellular or even the molecular level, we only see the very far removed macro-scale effects of a myriad of intertwined processes.
mirceal 4y ago
hah. not even close. we had moderate success in understanding and modeling some phenomena, but in the grand scheme of things we don’t know much. which is both scary and great if you have a curios mind

mirceal 4y ago

not only that, but our gut is literally the 2nd brain of our bodies. Read somewhere that there are more than 200 million in our gut. To put it in perspective, that’s more neurons that all the neurons in a dog’s brain.

layer8 4y ago

> a study that takes 1 liter of blood and just documents every chemical structure found (at any concentration) That’s because we don’t actually have the technology to do that. You can test for specific compounds that you know how to test for, and if their concentration is high enough. But there’s currently no way to e.g. go through a given sample molecule by molecule.

DantesKite 4y ago
Both these comments are a great way of putting it. I never thought about this before. Very interesting.
daanlo 4y ago
I thought you would be able to do this with a mass spectrometer. Although you would probably need a lot of blood :)
- gxt 4y ago
  Exactly, IBM can make movies using individual atoms, surely we aren't too far from being able to look at molecular structures and deduce what compounds are in a sample of blood.
- heavyset_go 4y ago
  You'd typically need reference samples if you're trying to get a typical lab to analyze compounds via mass spectrometry, which would make identification of unknown substances in blood hard for non-researchers.
- montecarl 4y ago
  A mass spectrometer by itself, will tell you the mass to charge ratio of ions in a sample. In most samples the molecules themselves are not ions naturally and need to be ionized. This can be done using a number of techniques, but a common one is electron impact ionization, where electrons are slammed into molecules causing them to fragment into charged ions. This smashes the molecules up into small charged chunks which can then be analyzed by the mass spec. These mass spectra are good fingerprints for the original molecule and can be mapped back to what molecule must have been smashed to produced them. However, if you try to analyze the mass spectrum of a mixture of molecules that are similar you will not be able to deconvolute the result into any unique answer, i.e. there will be many possible mixtures of molecules that could have resulted in the mass spectrum. This limitation of mass spectrometry can be overcome by first separating out the mixture of molecules you want to analyze into different fractions before they are ionized and enter the mass spectrometer. One common way to do this is to use a gas chromatography column. This works by first heating the sample so that it turns into a gas, and then passing it through a long column that is packed with a material that will interact with the gas and slow some molecules more than others. Often it is packed with silica. In this way you get the technique called GC-MS (gas chromatography/mass spectrometry). GC-MS is a fantastic technique for analyzing complex mixtures but it will have its limits if there are too many different types of molecules in the mixture. In blood there will be tiny molecules like O2 and CO2 and giant macro-molecules like DNA. There is no technique I know of that can analyze such a wide range of molecular masses in one go. Plus mass spectrometry doesn't directly give you the structure just the masses of the fragments after you blow up the molecules (or the total mass if a more gentle ionization technique is used as is sometimes done for macromolecules). I write all this just to explain how there aren't any analytical instruments that you just inject a sample into and out pops all the chemicals and their concentrations. Blood is a amazing soup of different elements and molecules and a full analysis requires a large number of steps and different analytical techniques to get even close to fully characterizing.