You'd have to be crazy to add 2.5 grams worth of MSG to a single meal. Accent calls for using like 1/10th that amount in soup. That's no different than using 10x as much salt as a recipe calls for, it's not going to turn out so great.
Depending on the size of the pot that might be about right. The problem I have with the studies referenced is that they wildly overestimated MSG intake and their threshold effect was at a level similar to eating one of those heaping tablespoons of MSG by itself with no food. I'm sure MSG produces some noticeable effect at some point but those studies make it seem like the threshold they found was consistent with the amount you could plausibly eat in a normal meal seasoned with MSG.
That's something like 40 to 50 grams. Say it's an 8 liter pot, serving 16. That's like 2.5g to 3.1g per person, ouch! Then there is glutamate in that pot already from natural sources as well as possibly ingredients like processed meats and whatnot.
No, it's actually more like 24g to ~30g depending on how "heaping" the tablespoons were, you might be thinking of the specific gravity and using that to estimate the weight but an important consideration is that it's in a small crystalline form. 1/4 tsp of MSG is 1.0g which puts a tbsp at 12g. An estimate of only 16 servings is probably a bit on the low side as well. Even assuming all of that, that still only amounts to 24 mg/kg for a 70kg person whereas the paper you referenced indicated there was a threshold effect and used doses of 150 mg/kg.
> might be thinking of the specific gravity and using that to estimate the weight but an important consideration is that it's in a small crystalline form
I'm relying on the density of MSG being similar to that of sugar, and both being in crystalline form, then working from information around the web about the mass of heaped tablespoons of sugar.
(I know that not all crystals are of the same shape and not all pack the same. Something with needle-like crystals will end up fairly fluffy, unless mechanically crushed.)
In the paper I cited there is a reference to another one by Shimada, et al. 2013. Those researchers estimate the daily intake of MSG in industrialized countries to be between 50 mg/kg and 200 mg/kg. (That reference is given in section 2.4.1, p. 76).
So you're saying that MSG doesn't cause headaches, because nobody would be crazy enough to put 2.5 grams of it into the meal consumed by a 50 kg person? Or what is the logic here?
The paper cites at least two other studies which found that 150 mg/kg daily doses caused headaches: to 100% of the subjects in one of the studies, and more than 50% in the other.
The paper you cited references three other papers. The first paper just throws out an estimate with no source or data for it, just a figure. That figure is also not in mg/kg just total dietary intake. Honestly the figure itself is believable as it claims 0.3g to 1.0g per day which works out to 4.3mg/kg to 14.3 mg/kg for a 70 kg person.
The second paper isn't listing MSG or even just free glutamate, it's listing all glutamate content which as you pointed out in another comment, is not comparable.
The third paper cited appears to be where they got their wildly wrong claim of 50 mg/kg to 200 mg/kg from but this literally just cites the first two papers. I'm assuming they just converted the glutamate figures in the second paper and assumed all of that was MSG.
Either way the claim that average daily intake of MSG is between 50 mg/kg and 200 mg/kg is just flat out unfounded and wrong. The very first source they cite lists a figure less than 1/10th that amount and obviously does not support their claim. And keep in mind, a 150 mg/kg dose for an average person is 10.5 g, that's over 20x the recommended serving size.
