Even though MSG is technically gluten-free, many people have a similar reaction as with gluten. The theory is that some symptoms of autism are made worse because of glutamate receptor disfunction. There is a lot of chemistry involved, and I don't understand all of it, but there are some simple rules:
Foods rich in glutamate and aspartate:
1) Grains: Wheat, barley, and oats are highest. Corn and rice are lower than wheat but higher than potatoes.
2) Dairy Products: All Cheeses are very high. Casein is very concentrated in cheese and is about 20% glutamic acid. (That is one reason why ASD kids respond to GFCF, according to the theory.)
3) Beans: Especially Soy, but really all of them.
4) Seeds: Including Sunflower, sorry.
5) Peanuts: Very high in glutamate. Also cashews (sorry), and almonds. You can't eliminate these, but you can enjoy in moderation.
6) Diet drinks: Try to stay away because of aspartate (aspartame/NutraSweet)
7) Prepared foods, and especially soups can be loaded with MSG
8) Meats: All meats are naturally rich in glutamate and aspartate. Turkey is pretty high, but eggs are pretty low. If you must eat meat, try lamb.
So what can you eat?
5) Tree nuts (pecans and walnuts for example, are lower than peanuts and cashews).
Don't go crazy, though. You can't eliminate glutamate from your diet. The best you can do is cut back. Many people find that the more they cut back, the better they feel, but not everyone notices any difference.
For me, for example, I don't notice anything. But my son has dramatic improvements when we limit his glutamate.
This is an interesting article and a good reason to shop at Whole foods and not Walmart.
MSG makes my son hyper just after eating outside in restaurants like Panda Exp.. as they are fond of adding MSG to their food like other chinese restaurants to improve taste. It's definitely better to avoid them.
It is easy to avoid MSG (eg in soy sauce and as an additive) in diet by cooking at home using as much organic stuff as possible but as mentioned above removing glutamate is impractical nor healthy. There are about a half a dozen compelling reasons why removing milk is a good idea but I wouldn't rank glutamate as one of the top reason at least not for us. For us removing dairy milk makes a big difference but not gluten. It is trial and error to figure out. Removing all additives and MSG is the easy part.