MSG — monosodium glutamate — might be the most successfully slandered molecule in food history.
The backstory: in 1968, a single speculative letter to a medical journal coined 'Chinese Restaurant Syndrome,' blaming MSG for headaches and numbness. The idea stuck, carrying more than a little xenophobia along with it, and decades of avoidance followed.
The science that followed didn't cooperate with the panic. Controlled, blinded studies could not reliably reproduce reactions to MSG, even in people who identified as sensitive; responses appeared at the same rates with placebo [1]. The FDA classifies MSG as generally recognized as safe [2]. And here's the kicker: glutamate is everywhere nature wants food to taste good — parmesan, tomatoes, mushrooms, breast milk. Your body treats glutamate from a shaker and glutamate from a tomato identically.
Does that mean nobody ever reacts to a heavily seasoned meal? People react to meals for lots of reasons — portions, fat, salt, alcohol, expectation. But the specific 'MSG causes it' claim has failed its trials for fifty years.
Why rootd still lists MSG on scan results: transparency, not alarm. Some people prefer to avoid it, and that's their call to make — but it sits in our 'worth knowing' tier, not the danger tier. The real lesson is the pattern: a scary story about an ingredient can outlive decades of evidence against it. It's why we cite sources instead of vibes.