Sodium glutamate is rather controversial substance. It is used to enhance the flavour of food, to bring out the umami. While it's not banned by any laws or even have any regulations from food and health authorities some organizations have banned it's usage in their food production and many food companies have been advertising eagerly their glutamate free products.
Sure, sodium glutamate, or MSG, also known as E621 can kill you. While not as dangerous as sodium chloride you will be in grave danger if you'd consume over 1 kg of it. Why is it then that this MSG is so feared while the other is present in almost every food? Nobody is suggesting banning sodium chloride, except maybe your doctor who actually knows salt is bad for tour blood pressure.
Glutamate is actually essential to our brain functions. There has been claims that MSG has cause symptoms like headache and it doesn't take long for somebody to connect the dots. Clearly it must be affecting our glutamine levels in our brains negatively, or something. At the same time somebody saw the opportunity and started selling "magic" brain boosting pills based on the same substance. And of course either does work as the consumed glutamine never reaches your brains.
So what do they put in the food now that MSG is so bad for you? That other flavour enchanting poison I mentioned earlier, other glutamine containing extracts not named MSG or E621 like yeast extract. Nothing has changed, the stuff is just made from something else. Something, which health effects and safety hasn't been as comprehensively studied.