Yet few entries in the dictionary of food additives arouse quite as much hostility as MSG, used to heighten flavour in snacks and crisps, stock cubes and packet soups, canned meat and vegetables. People cannot help associating it with Chinese Restaurant Syndrome, characterised by palpitations of the heart, dizziness, nausea, fainting, muscle pains and numbness, cold sweat around the face and armpits, vice-like headaches, migraine symptoms. Some food critics also complain that MSG is used excessively to lift cheap ingredients that have the fresh flavour knocked out of them during food processing.
The Glutamate Information Bureau in London, entrusted with improving public perception of this most unpopular additive, has come up with yet another alias. It prefers to call MSG by its Japanese name, umami - which means 'deliciousness'. In fact, the bureau's sister organisation in America already calls itself the Umami Information Centre.
It may sound like a damage limitation exercise, but the bureau's message is not just one of semantics. MSG, it points out, has been passed as safe by everyone - the British and American governments, the EC, the World Health Organisation and the United Nations Food and Agriculture Organisation. The food critics are not right, the bureau maintains, when they say MSG can be used to disguise second-rate food. Used like sugar and salt to heighten flavour, MSG cannot improve poor ingredients. It can only enhance good ones.
The Chinese Restaurant Syndrome (CRS) has been more difficult to refute, especially among people who have suffered from it. As long ago as 1968, Dr Lee Ho Man Kwok singled out the excess use of MSG in Chinese kitchens as the cause of palpitations and headaches, which he called the Chinese Restaurant Syndrome. It was also known as Kwok's disease. In London, hospitals closest to Chinatown in Soho confirmed that they often had patients coming to them after Chinese meals, complaining of these symptoms.
Must be some mistake, says the bureau. Tests in America among people claiming to be susceptible to CRS have shown they responded in a similar way to other foods such as tomatoes, oranges and coffee, suggesting they were probably hyper-allergenic types.
It is the glutamic acid in many foods that produces the savoury taste the Japanese refer to as umami. In the West, we generally accept that the taste buds discriminate between four basic flavours - sweet, sour, salt and bitter. The Japanese regard umami as a fifth flavour. Sensed by taste buds at the back of the mouth, it is essentially the flavour of a salty meat stock or broth. They have known it for centuries through the seaweed laminaria japonica, added to soups to heighten flavours. In 1908 Professor Kikunae Ikeda isolated the active chemical as monosodium glutamate, and since then it has been increasingly available in powder form.
For the consumer, the parallel with salt is a pointed one. Like sodium in salt (sodium chloride), glutamic acid in MSG occurs naturally in many foods. It is also like sugar, which is present as sucrose, fructose and lactose in fruits, honey and milk. Like sugar and salt, MSG is a concentrate. For this very reason, Alan Long, scientific advisor to the Vegetarian Society, takes a strong objection to it. 'Concentrated sugar and salt are the cause of our undoing,' he says. But he has no objection to eating foods where glutamic acid occurs naturally. 'It gives a tingle factor. Glutamic acid acts on the nervous system.' It is one reason why Italian food is so tasty. Tomatoes have particularly high levels, as does cheese - none higher than Parmesan. So do black olives and tinned anchovies. And mushrooms and celery.
MSG is made commercially by fermenting a cheap carbohydrate such as sugar beet or molasses or sage, with ammonia. It also occurs during the fermentation of the soy bean.
So fermented black bean sauces, and bean pastes like miso, have the glutamate tingle factor - as do soy and Worcester sauce. So do those pungent Thai and Vietnamese relishes, the fish sauces known as Nam Pla and Nuoc Mam. Enjoy them, says Long, recommending the Japanese Kikkomen brand of soy sauce as being the most naturally slow-fermented.
How do MSG's resolute opponents now view it? I spoke to Maurice Hanssen who compiled E for Additives, the book that first sounded alarm bells over some of the 'safe' additives nine years ago. He took a strong line against MSG in his first edition, but has modified it in later revisions, accepting much of the research put forward by the Umami Information Centre. But he is not entirely convinced of its safety, and cites animal experiments that show it can cause damage to brain cells. He is convinced that it should not be permitted in infant food, since US research in 1970 suggested it could damage the immature brain.
Hanssen is confident that the way MSG is used in the food industry is entirely safe, but is not happy about the way it is used carelessly in Chinese restaurants. 'You can be zapped by a takeway meal.' He was told the industry actually sent out instructions to restaurants, in Chinese, advising them to use it in moderation. 'As I understand it, they owned up.'
If you get CRS (even though the Bureau says you cannot get it from MSG), reassure yourself with this thought, says Hanssen: the discomfort caused by an overdose will only last while the MSG remains in the system, and is often over by the next day.
'No one has ever died from eating too much MSG,' confirms the Chinese cookery writer Yang-Kit So, author of the recent Classic Cuisine of China. But on taste grounds, she deplores its widespread and excessive use. 'I don't use it. It gives everything the same flavour. In Chinese homes, it's not used very much.' But, she concedes, it is used universally throughout the Orient. 'The Japanese swear by it. In China and Taiwan it's known as Brain Food, and it's in every recipe. Not very much, it's true, but people always use more.'
She herself experienced CRS as long ago as the 1960s, in a Chinese restaurant in Philadelphia. She also remembers a time in Britain in the 1970s when everyone was complaining about CRS in Chinese restaurants. 'But it has got much better now,' she maintains.
Yang-Kit So says she has been invited to an umami seminar, but remains sceptical about the taste claims. 'They organised tastings to show that foods with it tasted better than those without it. I take a cynical view; you can do it cleverly by providing a very good, well-made chicken soup, for example, and adding a pinch of MSG to that. I prefer to do without it.'-Reuse content