[HN Gopher] Cysteine depletion triggers adipose tissue thermogen...
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       Cysteine depletion triggers adipose tissue thermogenesis and weight
       loss
        
       Author : bookofjoe
       Score  : 81 points
       Date   : 2025-06-05 16:33 UTC (6 hours ago)
        
 (HTM) web link (www.nature.com)
 (TXT) w3m dump (www.nature.com)
        
       | zajio1am wrote:
       | (In mice)
        
         | myst wrote:
         | (So far)
        
           | r2_pilot wrote:
           | (also observed to be lethal in cases)
        
         | mbil wrote:
         | This 2012 study in humans says
         | 
         | > Since this was also a noninterventional study, two
         | possibilities for interpretation of the findings were either
         | that a high cysteine somehow promotes obesity or that obesity
         | influences cysteine turnover, thereby raising plasma tCys.
         | 
         | https://onlinelibrary.wiley.com/doi/full/10.1038/oby.2011.93
        
       | jdnier wrote:
       | An overview of other studies investigating cysteine and glycine
       | sources and effects (from 2023; video or transcript):
       | 
       | https://nutritionfacts.org/hnta-video/how-to-get-less-cystei...
        
       | jostmey wrote:
       | This should only act as a clue into driving weight loss.
       | Depleting of cysteine is severe. It would be depriving a team
       | from writing html and discovery the code runs faster... very
       | drastic imposition
        
       | LPisGood wrote:
       | Cysteine is also an irreplaceable building block of vital
       | proteins required to sustain life. It's unclear if there is any
       | potential benefit of applying these findings to the problem of
       | human weight loss or fitness.
        
         | kens wrote:
         | Cysteine is not an essential amino acid. Humans can synthesize
         | it from methionine.
        
           | bell-cot wrote:
           | Wikipedia's disclaimers on that: "Cysteine can usually be
           | synthesized by the human body under normal physiological
           | conditions if a sufficient quantity of methionine is
           | available."
        
         | gus_massa wrote:
         | I agree, for example Pepsin[1] that is the protein inside the
         | stomach that split proteins has Cysteine [2]
         | 
         | > _Pepsin forms three between the sulfur atoms of cysteine
         | residues in the peptide chain which hold important roles in the
         | folding of the protein and stabilizing the two domains_
         | 
         | [1] https://en.wikipedia.org/wiki/Pepsin
         | 
         | [2]
         | https://biology.kenyon.edu/BMB/jsmol2021/Cat_Marko/index.htm...
        
         | User23 wrote:
         | I would make a stronger statement and say that this belongs
         | squarely on the effect and not the cause side.
         | 
         | I could be wrong, but I doubt it. Amino acid depletion sounds
         | way more likely to be due to some kind of disruption in
         | homeostasis rather than dietary intake.
        
       | readthenotes1 wrote:
       | "Systemic cysteine depletion in mice causes lethal weight loss"
       | 
       | I didn't read much after that
        
         | dr_kiszonka wrote:
         | Maybe you should have.
        
       | bilsbie wrote:
       | Is this the same as homocysteine?
        
       | poirot2 wrote:
       | Funny because cysteinuria doesn't do this (pee out cysteine)
        
       | RS-232 wrote:
       | Cysteine protease inhibitors could be used to reduce free
       | cysteine available to cells. Some natural sources of those are
       | papaya, kiwi, pineapple, fig, apples, and rice.
        
         | meew0 wrote:
         | Cysteine proteases are named after their reaction mechanism,
         | which involves a key cysteine residue within the _enzyme_. It
         | doesn 't have anything to do with the amino acids in the
         | cleaved proteins.
        
       | riknos314 wrote:
       | The phrasing of the title and paper steer the interpretation
       | towards reducing cysteine as a method for increasing weight loss,
       | however I think that the much more interesting takeaway is this:
       | 
       | > Notably, restoration of up to 75% cystine levels in the diet of
       | Cth-/- CysF mice that were undergoing weight loss was sufficient
       | to completely rescue the body weight
       | 
       | This might indicate that cysteine depletion could be one
       | mechanism present in some wasting diseases, and that strategic
       | supplementation of cysteine may be beneficial in reducing
       | excessive weight loss in such diseases. I would be quite
       | interested to see future research in this area.
        
       | biomcgary wrote:
       | Cysteine plays a key role in redox metabolism and removing
       | reactive oxygen species (ROS). During brown fat burning, high
       | flux of electrons increases the NADH/NAD+ and FADH2/FAD ratios --
       | shifting redox state toward a more reduced environment, which is
       | exactly what you would need if deprived of cysteine.
        
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       (page generated 2025-06-05 23:01 UTC)