FYI: Is monosodium glutamate (MSG) bad for you?

PUBLISHED : Sunday, 11 November, 2007, 12:00am
UPDATED : Sunday, 11 November, 2007, 12:00am

Cold sweats, lung spasms, migraines - these are just a few of the side-effects attributed to the innocent-looking flavour enhancer known as MSG, which has a presence on dinner tables worldwide but is especially beloved in Asia.

First, to dispel a common misconception, MSG is not a chemical cooked up in a dimly lit corporate lab, but the salt form of an amino acid occurring naturally in the human body and high-protein foods such as beans, cheese and fish. It was isolated from seaweed a century ago by University of Tokyo researcher Kikunae Ikeda, who singled it out as the agent giving many Japanese dishes the unique, savoury flavour he termed umami.

Just as it was in Ikeda's day, MSG is drawn from natural sources such as beets and sugarcane through a fermentation process similar to those used to produce beer and soy sauce. Ajinomoto, the company set up to commercialise Ikeda's discovery, still dominates the MSG market, producing about one-third of the global supply.

A decades-long debate has raged over whether MSG is, as Ajinomoto argues, part of a well-balanced diet or a few short steps away from poison. In 1959 the United States Food and Drug Administration (FDA) classified the substance as 'generally recognised as safe', just like salt, vinegar and baking powder. The European Union has given consumers the green light to ingest as much MSG as they can handle, as has the United Nations Food and Agriculture Organisation, which has placed the additive in its most risk-free category of food ingredients.

But there's also ample anecdotal evidence that MSG is responsible for at least some discomfort among the world's diners. A report in the prestigious New England Journal of Medicine in 1968 first raised the spectre of 'Chinese restaurant syndrome', with a Dr Ho Man-kwok detailing a 'strange' ailment every time he ate MSG-laden Chinese food. It was characterised by 'numbness at the back of the neck, gradually radiating to both the arms and the back, general weakness and palpitations'.

Nearly three decades later, the FDA admitted MSG could produce allergy-like symptoms and said it was considering stricter labelling requirements for products containing it, though it has yet to come up with any.

Groups such as the Truth In Labeling Campaign have accused regulators of being under the thumb of the processed-food industry and cited tests linking MSG to headaches and asthma in humans and nerve disorders in animals. But agencies such as the FDA (and companies such as Ajinomoto, naturally) insist these tests weren't controlled experiments and there is no conclusive evidence MSG causes any health problems.

So whether MSG is perfectly healthy or a hazard remains a decision left largely to the individual. Anyone who consumes it and experiences one or more of what the FDA has listed as possible signs of MSG intolerance - tingling skin, difficulty breathing, headaches, drowsiness or nausea - should steer clear of it.

Those who do decide to avoid MSG completely will soon discover it's no easy task. The additive is present in one form or another in everything from instant noodles to tinned soup and potato crisps. And since a lot of manufacturers are conscious of the suspicion surrounding MSG, glutamates are often given aliases in ingredient lists, including 'natural flavourings', 'yeast extract', 'gelatin' and 'textured protein'.