It has been testified many times on this forum that a healthier diet leads to less severe POIS symptoms, and a shorter POIS attack duration. That is not a cure in itself, but a great improvement.
This healthier diet changes includes avoiding any nasty additive like aspartame, nitrites, and of course, monosodium glutamate ( MSG), which is neurotoxic, something you really want to avoid when POIS already causes cognitive and emotional symptoms. In order to really avoid MSG, you have to be a good label reader, because it is hidden under many names. In fact, it is present in almost all processed food, to add flavor to otherwise "dead" stuff. You can find lists of those many names, like here:
http://www.truthinlabeling.org/hiddensources.html .
So,
avoid any food having this in the ingredient list, because it contains MSG for sure: Glutamic acid (E 620)2
Glutamate (E 620)
Monosodium glutamate (E 621)
Monopotassium glutamate (E 622)
Calcium glutamate (E 623)
Monoammonium glutamate (E 624)
Magnesium glutamate (E 625)
Natrium glutamate
Anything “hydrolyzed”
Any “hydrolyzed protein”
Calcium caseinate, Sodium caseinate
Yeast extract, Torula yeast
Yeast food, Yeast nutrient
Autolyzed yeast
Gelatin
Textured protein
Whey protein
Whey protein concentrate
Whey protein isolate
Soy protein
Soy protein concentrate
Soy protein isolate
Anything “protein”
Anything “protein fortified”
Soy sauce
Soy sauce extract
Anything “enzyme modified”
Anything containing “enzymes”
Anything “fermented”
Anything containing “protease”
Vetsin
Ajinomoto
Umami
Here are other possible sources , so these are suspect ingredient names possilbly containing MSG, although not 100% sure like the one above: Carrageenan (E 407)
Bouillon and broth
Stock
Any “flavors” or “flavoring”
Natural flavor
Maltodextrin
Oligodextrin
Citric acid, Citrate (E 330)
Anything “ultra-pasteurized”
Barley malt
Malted barley
Brewer’s yeast
Pectin (E 440)
Malt extract
Seasonings
You will first be amazed at how many products do contains MSG.
Don't forget that the meat flavoring called "Accent", here, is pure MSG !!! Also, commercial chicken and beef broth like Bovril contains a huge amount of MSG.
Why is there so much MSG in food ? In short, MSG stimulate a lot the taste buds, which gives life to dead, cheap food. It also have the "addictive" effect you have when eating chips. The effect of MSG is so strong on your brain that you want more of this. That's part of why it is hard to eat only one piece of chips and stop there. Powerful stuff, indeed, no wonder why all companies put this in their product, and obviously not for your better health ! In the end, again, it's all about the money. Other nasty additive like aspartame/nutrasuc have less names by which they hide, but MSG is in so much industrial food that labeling has been very creative to hide it.
So, read labels, avoid nasty artificial ingredients and toxic additives, and I assure you you will see the benefits in a few months. You cannot eat chemicals like nitrites, aspartam and MSG, artificial color and flavors, and preservatives, and have nod effect on your body. All those are upsetting your immune system, and that's not what you want if you have POIS.