3 ms·

Uh. I actually have an MSG sensitivity which took me forever to figure out what it was. For decades I'd occasionally be eating in a restaurant and my lips, tong

Uh. I actually have an MSG sensitivity which took me forever to figure out what it was. For decades I'd occasionally be eating in a restaurant and my lips, tongue and/or back of my throat would go numb. It wasn't until I bought MSG and started putting it on pretty much everything in larger doses that I realized it was the culprit. I can reproduce it pretty easily by simply putting nothing but MSG on my tongue. It takes a good bit to do it however and seems to cause me no other problems so I tend not to worry about it, but it is clearly some kind of sensitivity or allergy which is easily reproducible and not the slightest bit vague (lips going numb is a pretty easily identifiable sensation). Claiming it is all completely made up seems a bit premature.

ricardobeat 13y ago
It is said that the human body itself produces up to 50g of glutamate every day; an allergy to it should result in much more terrible effects than superficial numbness. Someone already posted a longer explanation: http://www.metafilter.com/131105/Dorito-Powder#5147903 http://www.metafilter.com/131105/Dorito-Powder#5147903
- Aloisius 13y ago
  It could also be the large amount of sodium that gets released when it touches my tongue as well, but the effect is undeniable.
- ars 13y ago
  > produces up to 50g of glutamate every day But not as free glutamic acid, and that makes a HUGE difference.
  - brianleb 13y ago
    Really? Please observe the differences between https://en.wikipedia.org/wiki/File:L-Glutamate_Structural_Formulae.png https://en.wikipedia.org/wiki/File:L-Glutamate_Structural_Fo... and https://upload.wikimedia.org/wikipedia/commons/f/ff/Glutamins%C3%A4ure_-_Glutamic_acid.svg https://upload.wikimedia.org/wikipedia/commons/f/ff/Glutamin... . The only difference is the relocation of hydrogen ions, which is a normal and expected occurrence of all molecules in the presence of other molecules. The equilibrium of these different forms of the same molecule is mediated by pH, among other things. They are in fact the same molecule. The word "acid" only means that it likes to give up a hydrogen ion when given the opportunity.
    - ars 13y ago
      You understood me in reverse. In the body the glutamate (acid or not) is bound up with other things, i.e. not free. I said acid because my understanding was the MSG disassociates from the sodium once ingested.
      - tptacek 13y ago
        I read some glutamate metabolism papers last night and I don't think this is likely to be true at all. I think it's a manifestation of the naturalist fallacy: you believe the "free glutamic acid" released by the dissolution of MSG to be artificial and are trying to rationalize a distinction for the glutamates that the body produces that doesn't exist. In reality, glutamic acid isn't simply an amino acid that happens to be present in the human body. It is fundamental to the way our bodies work; it's required for nitrogen metabolism! Glutamate toxicity seems very unlikely.
        ars 13y ago
        > ... naturalist fallacy: you believe ... distinction ...that doesn't exist. I believe no such thing. I don't know what you read, but in the body glutamic acid doesn't just float around randomly, it's carefully stored near the nerves that need it. Excess glutamic acid where it doesn't belong causes nerve problems. It's like the difference between sucrose and starch. Chemically they are the same, but the effects are very different because one needs more digestion than the other.
        tptacek 13y ago
        Your body can't metabolize nitrogen without glutamic acid. It's part of how you, and I think maybe all the rest of your siblings in phylum chordata, build proteins. I don't see a lot of reason to believe that it causes "nerve problems" in the human body, but would welcome a citation to the literature that shows that. It gets worse for your argument. Here's a paper that demonstrates that very large oral doses of MSG in both mice and humans don't even significantly raise the plasma concentration of glutamates. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3136011/ http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3136011/ This should probably be unsurprising. Your body is designed to deal with consumption of glutamates; in fact, even though it's so vital to your system that you produce it yourself, humans get most of their glutamic acid from dietary sources. Hypersensitivity to dietary glutamate would be maladaptive. The idea that your body has carefully delineated locations where it's safe to have glutamic acid (probably not coincidentally in the nervous system, the most complex part of the body), and that ingesting "artificial" sources of glutamic acid throws that out of whack, is again I think a manifestation of the naturalistic fallacy.

ricardobeat 13y ago

It is said that the human body itself produces up to 50g of glutamate every day; an allergy to it should result in much more terrible effects than superficial numbness. Someone already posted a longer explanation: http://www.metafilter.com/131105/Dorito-Powder#5147903 http://www.metafilter.com/131105/Dorito-Powder#5147903

Aloisius 13y ago
It could also be the large amount of sodium that gets released when it touches my tongue as well, but the effect is undeniable.
ars 13y ago
> produces up to 50g of glutamate every day But not as free glutamic acid, and that makes a HUGE difference.
- brianleb 13y ago
  Really? Please observe the differences between https://en.wikipedia.org/wiki/File:L-Glutamate_Structural_Formulae.png https://en.wikipedia.org/wiki/File:L-Glutamate_Structural_Fo... and https://upload.wikimedia.org/wikipedia/commons/f/ff/Glutamins%C3%A4ure_-_Glutamic_acid.svg https://upload.wikimedia.org/wikipedia/commons/f/ff/Glutamin... . The only difference is the relocation of hydrogen ions, which is a normal and expected occurrence of all molecules in the presence of other molecules. The equilibrium of these different forms of the same molecule is mediated by pH, among other things. They are in fact the same molecule. The word "acid" only means that it likes to give up a hydrogen ion when given the opportunity.
  - ars 13y ago
    You understood me in reverse. In the body the glutamate (acid or not) is bound up with other things, i.e. not free. I said acid because my understanding was the MSG disassociates from the sodium once ingested.
    - tptacek 13y ago
      I read some glutamate metabolism papers last night and I don't think this is likely to be true at all. I think it's a manifestation of the naturalist fallacy: you believe the "free glutamic acid" released by the dissolution of MSG to be artificial and are trying to rationalize a distinction for the glutamates that the body produces that doesn't exist. In reality, glutamic acid isn't simply an amino acid that happens to be present in the human body. It is fundamental to the way our bodies work; it's required for nitrogen metabolism! Glutamate toxicity seems very unlikely.
      - ars 13y ago
        > ... naturalist fallacy: you believe ... distinction ...that doesn't exist. I believe no such thing. I don't know what you read, but in the body glutamic acid doesn't just float around randomly, it's carefully stored near the nerves that need it. Excess glutamic acid where it doesn't belong causes nerve problems. It's like the difference between sucrose and starch. Chemically they are the same, but the effects are very different because one needs more digestion than the other.
        tptacek 13y ago
        Your body can't metabolize nitrogen without glutamic acid. It's part of how you, and I think maybe all the rest of your siblings in phylum chordata, build proteins. I don't see a lot of reason to believe that it causes "nerve problems" in the human body, but would welcome a citation to the literature that shows that. It gets worse for your argument. Here's a paper that demonstrates that very large oral doses of MSG in both mice and humans don't even significantly raise the plasma concentration of glutamates. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3136011/ http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3136011/ This should probably be unsurprising. Your body is designed to deal with consumption of glutamates; in fact, even though it's so vital to your system that you produce it yourself, humans get most of their glutamic acid from dietary sources. Hypersensitivity to dietary glutamate would be maladaptive. The idea that your body has carefully delineated locations where it's safe to have glutamic acid (probably not coincidentally in the nervous system, the most complex part of the body), and that ingesting "artificial" sources of glutamic acid throws that out of whack, is again I think a manifestation of the naturalistic fallacy.