Monosodium glutamate, or MSG, mei jing, ajinomoto, Ac'cent or gourmet powder, is probably the most controversial flavouring. Some people say it is never necessary to add MSG, believing that if you use top-quality ingredients and prepare food properly it will have enough flavour. Others believe food is bland without MSG and use it indiscriminately, adding it to everything except desserts and beverages. Some blame it for ailments including migraines, shortness of breath, lethargy, tension, dizziness and backache. Others consume it with no adverse reactions.
The white, shiny crystalline substance was developed in 1908 by Japanese chemistry professor Kikunae Ikeda, who noticed that when he added dried kombu (giant kelp) to food, it made savoury dishes taste better. He believed there was something in the seaweed that enhanced the flavours of other foods and figured out a way to isolate this 'essence'. It turned out to be glutamate, which is derived from glutamic acid, one of more than 20 amino acids contained in all animal and vegetable proteins. Glutamate occurs naturally in a wide range of disparate ingredients such as human breast milk, seaweed, fish and soy sauces, meat, peas, Parmesan cheese, tomatoes and mushrooms. The glutamate's ability to increase the savouriness and 'meatiness' of foods is receiving increasing recognition as a fifth 'taste', along with bitter, sweet, salty and sour. Ikeda called this flavour umami (deliciousness).
In his essay Why Doesn't Everybody In China Have A Headache? food writer Jeffrey Steingarten tackles the question of whether MSG really is to blame for all the symptoms it purportedly causes. He points out that nobody seems to react to MSG in China and Japan, two countries where it is used widely. It is possible that people who do not show symptoms have built up a tolerance. The United States Food and Drug Administration categorises MSG as 'generally recognised as safe' for healthy people when consumed at 'customary levels', but requires food manufacturers to list it on labels. Studies have shown that the symptoms are sometimes psychosomatic, with subjects showing random results with both the placebo and MSG test samples.
Unfortunately, when we dine out, we cannot be sure we are consuming safe levels of MSG. Some restaurant cooks mix the powder into the salt and therefore add a dose of it every time they salt a dish. While I do not have a bag of MSG in my cupboard, I might add it in small amounts in the form of 'hydrolysed vegetable (or soy) protein', 'flavour enhancer', 'yeast extracts,' or 'natural flavourings'. These are just a few of the names MSG goes by in prepared food products such as canned broths, spice mixes and bouillon powders and cubes.