Monosodium glutamate (MSG) is a white synthetic crystalline substance which is added to some foods for flavor enhancement. MSG itself does not add flavor to foods; rather, it heightens the eater's response to the flavors already in the foods. It has no nutritional or preservative value.
Although the FDA considers MSG generally safe, some people experience relatively short‐lived adverse effects. Symptoms vary from person to person, but may include:
- Burning sensation
- Dizziness
- Headache
- Palpitations
- Thirst
- Chest pain
- Drowsiness
- Nausea
- Stomach pain
- Tight chest
- Diarrhea
- Flushing
- Numbness
- Sweating
- Vomiting
Symptoms may occur very soon after consuming MSG‐treated food, if the dose is sufficiently high, and may persist for 1‐2 hours. There is still much controversy over why MSG produces these symptoms. Various biochemical effects have been investigated. Some studies even dispute the idea that MSG can cause any unpleasant side effects. The only way to determine whether or not an individual is intolerant of MSG is by a challenge procedure, in which the patient is given varying doses of MSG and symptoms are monitored.
If you want to avoid MSG, you always must read ingredient labels carefully for monosodium glutamate; in addition, other terms on food ingredient lists may indicate the presence of MSG, without using its specified name. Some types of foods do not contain this substance, but others almost always have it.
These food ingredients should be avoided because they may contain free glutamate:
- Autolyzed yeast extract
- Flavorings
- Kombu extract
- Sodium caseinate
- Baker's yeast extract
- Hydrolyzed plant protein
- Yeast extract Natural flavorings
- Calcium caseinate
- Hydrolyzed vegetable protein
- Potassium glutamate
The following list indicates which foods you should be most careful about:
- All Oriental food: Served in restaurants and purchased in grocery stores
- Frozen entrees: TV dinners, Mexican foods, pizza, meat pies
- Processed meats: Bologna, canned meats, hot dogs, lunch meats, sausages
- Vegetables: Frozen vegetables with sauces or seasoning
- Sauces/gravies: Most soy sauces (check the labels), canned/frozen/dried sauces and gravies
- Soups: Bouillon cubes, canned/dried soups, soups in restaurants
- Snack foods: Flavored chips, crackers, popcorn, puffs, etc.; frozen dairy products (such as ice cream and yogurt)
- Imitation foods: Imitation cheeses, imitation dairy products, Hamburger Helper‐type mixes, imitation meats, imitation nuts
- Beverages: Hot chocolate mixes