The first is fairly obvious. Migraine headache, asthma, skin rash, seizures, and irritability are some of the reactions that might be noticed after eating something that contains free glutamate -- something containing monosodium glutamate, hydrolyzed pea protein, autolyzed yeast, maltodextrin, or natural flavors, for example.
More difficult to make the connection, yet still discernible, ADHD, atrial fibrillation, and tachycardia are reactions that can be caused by eating food that contains free glutamate.
But you can’t see the brain damage that is caused by free glutamate. You can't see the brain damage in progress when a neuron here and a neuron there is destroyed by consumption of just a little more free glutamate than is needed for normal body function. And you can't see the brain damage caused by free glutamate passed over the placenta to the the unborn (fetus) or the newborn by a pregnant or lactating mother -- brain damage that disrupts the endocrine system designed to regulated insulin and glucose secretion, appetite, and satiety and thus weight gain/control – the endocrine system designed to protect both males and females from reproductive disorders (such as infertility).
Monosodium glutamate, the food additive, was invented in 1908 at which time the glutamate component was produced by extracting glutamate from protein -- a slow and costly method.
It was reinvented in 1957 using genetically modified bacteria to produce glutamate. Following reinvention, virtually unlimited amounts of free glutamate became available, and great quantities of free glutamate, often in monosodium glutamate, were poured into processed foods. For the first time in history there existed the excessive amounts of free glutamate needed to produce excitotoxicity.
Since reinvention, there have been reports – and then increasing numbers of reports -- of tachycardia, arrhythmia, asthma, skin rash, depression, migraine headache, seizures, dizziness, mood swings, behavior problems in children, hyperactivity, anxiety, and more following the consumption of food containing manufactured free glutamate.
Since reinvention, there have also been increasing numbers of reports of gross obesity and reproductive disorders.
Just as a broken switch in a lamp might be fixable, a broken endocrine system might benefit from repair. But if the switch is gone, much as vulnerable brain cells are wiped out by free glutamate fed to the fetuses and neonates, the lamp will be beyond repair, just as those areas of the arcuate nucleus that have been wiped out by processed free glutamate will be beyond repair.
The young are most at risk from ingestion of free glutamate.