[tptacek]

People say things like this about gluten sensitivity, too, often with very detailed self-reporting. But in a controlled setting, outside of celiac, there's not a lot of evidence for NCGS, and it's very likely that a significant fraction of people who report NCGS are not in fact gluten-sensitive. As with MSG, people also have weird ideas about their gluten intake, and as with MSG there's widespread and easily illustrated sensitivity to other aspects of gluten-rich food (for instance, for a lot of people, rapid intake of lots of refined carbs will have immediate insulin effects).

The difference, of course, is that there is an underlying condition that makes gluten problematic for a small number of people --- celiac disease. There is no known "celiac of MSG", despite decades of searching for it.

Anything is possible, but the evidence overwhelmingly suggest that if you're having a reliable reaction to foods with MSG in them, it's something else in those foods you're sensitive to --- most likely salt! --- not MSG.

[1053r]

Just to expand on one of the parent's points, Celiac is pretty rare, and affects under 1% of the population. However, Fructose Malabsorption is much less rare, and affects closer to 5% in the US. In spite of the name, Fructose Malabsorption has little to do with dietary fructose, and instead has to do with a class of molecules called fructooligosaccharides (FOS).

Overconsumption of FOS causes bloating, nausea, "brain fog," lower GI upset, and a whole raft of other symptoms that sound an awful lot like what many self-diagnosed NCGS folks report. For folks with Fructose Malabsorption, the threshold consumption of FOS that causes symptoms is less than 10% the level that causes symptoms in the general population.

The confounding thing is that wheat is rich is FOS. So folks who believe they have NCGS stop eating wheat and sometimes feel better. They probably have Fructose Malabsorption, or are suffering from insulin spiking effects from refined carbs, or some other effect. But they heard gluten was bad for you, and when they ate the package of bread that said "gluten free," and stopped eating the normal wheat bread, they started feeling better.

"Middlebrow dismissals" of their condition don't really help them either. True, gluten is almost certainly not their problem. But gluten free food, as a side effect of lacking wheat, often helps them feel better! What are the chances that something similar is happening with MSG? Perhaps added MSG is often found along side other ingredients/contaminants that cause headaches and other reported "MSG symptoms"?

[kazinator]

> Perhaps added MSG is often found along side other ingredients/contaminants that cause headaches and other reported "MSG symptoms"?

MSG is a clear common denominator. Many people report that if they avoid anything with MSG (under any of its names), they avoid the associated problems. That doesn't mean it's MSG.

Why do studies focus on the MSG? Because they are sparked by the motivation to clear MSG's name (which could actually be right). They don't care about finding the root cause of these symptoms.

The proper scientific approach is to ignore the MSG hypothesis of the self-reported sufferers and get to the root cause, not simply to test that hypothesis and be done.

> "Middlebrow dismissals" of their condition don't really help them either.

Exactly; same in this MSG situation.

[tptacek]

Here we find ourselves hypothetically dismissing all the studies ever done on MSG based on broad classes of study design concerns.

[kazinator]

> Something else in those foods you're sensitive to --- most likely salt! --- not MSG.

Can you point to studies which confirm salt as the cause of these symptoms that MSG is unfairly blamed for?

I can eat consume copious amounts of salt without any ill effects, like finishing huge bowls of soup to the last drop.

I exercise a lot so I use salt liberally, and add it to water. If I don't supplement the salt intake, I start getting muscle cramps and a kind of lethargic feeling, particularly in hot weather.

I did an experiment, though, about 8 months ago: I started drinking bouillon. I prepared about a mug of hot water with a teaspoon of the soup stock. On one mug per day, I was okay. When I went up to three, the headaches and nausea showed up. I felt like crap, so I cut it short.

There is salt in that stuff, but that can't be it.

[pharrington]

The symptoms you're describing are also primary symptoms of dehydration.

A more reliable exploration would be, after diligently logging your food and drink intake (with time and quantities) along with your physical feelings for a couple months, add a daily regime of a specific amount of pure MSG. Start small, and increase the MSG intake until you start feeling adverse symptoms. Assuming symptoms manifest, then increase your daily hydration levels (obviously not to the point of giving yourself hyperhydration) and note when/if the adverse symptoms previously noted diminish.