The administration of monosodium glutamate at a dose of 30 mg/kg body weight was associated with development of excessive contents of low and middle molecular weight substances with reduced ability of kidneys to excrete toxic products.
30mg/kg, a typical guy weighs 70kg, so that's 2.1g.
They fed rats that much for 14 and 30 days, that's msg intake every single day for half a month or a full month.
The estimated average daily MSG intake per person in industrialized countries is 0.3– 1.0 g, but it depends on the MSG content in foods and an individuals’ taste preferences.
There are studies indicated that MSG intake at a dose of 3 g per day is dangerous to human health.
I weighed out 3g of MSG with a precision scale (yeah, the enclosed type), that's a lot. That's more than just a pinch which is what people use in typical cooking.
If you use that much MSG for meals
every single day, you have an issue. The issue is you don't know how to cook properly and rely on something artificial to bring flavours. Skill issue. Learn how to cook.
Parmesan cheese, mushrooms and tomatoes are all very high in glutamate. Parmesan contains like 1.7g/100g, a risotto uses how much of that? Cured pork is high in MSG, so is ham. A pasta meatballs dish sounds like a killer combo, give me a break.
Stop worrying about this dumb shit and eat healthy.
Keep salt intake to below 4g a day and only use a pinch of MSG when cooking, a normal person should never exceed an average intake of MSG that's remotely above 1g. You must be eating greasy Chinese takeaway for every single meal to achieve such high levels. I would wager that even a diet of Asian takeaway slop shouldn't reach 3g of msg a day.