Here is a comment on protein isolate which are found in protein shakes, drinks and bars. It is taken from the article linked above. The article is on coffee, which is pretty interesting.
Here is the low down on coffee (to find the particulars of the whys go to the linked article). Coffee should be organic and ground fresh (just before brewing). No sugar should be used. Coffee is acid forming so make sure you include a lot of fruits and veggies in your diet. Don't have decaffeinated coffee. Coffee also acts like MSG when ingesting excessive amounts so don't ingest too much. Coffee supposedly helps you stay young if you only have one cup at the most in a day. The water you use makes a big difference (this point was not in the article, but I have read other places that the fluoride and chlorine and such in water can do a lot of damage)."First of all, eat whole foods," Ori says. "Do not ever eat protein isolate… protein isolate doesn't have the alkalizing mineral co-factors that are needed to balance the acidity of the protein. This means that you should stay away from all whey isolate, hemp isolate, or soy isolate. These are extremely acidifying. If you keep using them in large amounts unbalanced by alkalizing foods, you risk metabolic acidosis.
Coffee inhibits this glutamate reabsorption. And when caffeine intake is too high and chronic, it can cause glutamate excitotoxicity. Glutamate excitotoxicity is also caused by MSG. MSG, when consumed in large amounts, creates glutamate toxicity, which causes brain cells' mitochondria to literally pop inside out…glutamate toxicity rapidly accelerates brain cell death...
But let's not panic. This is true only when MSG or caffeine intake is chronically high. If too much caffeine is being chronically absorbed, there is a high likelihood that similar to MSG, it could cause glutamate toxicity and related damage in certain areas of your brain."