An international team of experts has met to consider new evidence on the safety of the food additive, monosodium glutamate (MSG), which is used to enhance flavour in Chinese food and some processed food and beverage products. The resulting consensus was intended to replace a similar exercise published in 1997.
Total intake of glutamate from food in European countries was found to be stable at between 5 to 12 g/day. New evidence on immune function was scarce. In one study, 109 people with asthma were tested after consumption of oriental food or oral glutamate to establish tolerance. No adverse reactions were noted. Two studies investigating the impact of glutamate on lung function found no effect. There was no new evidence to support the idea that specific individuals experience sensitivity to glutamate.
Turning to concerns about the metabolic fate of glutamate, the expert panel spent some time considering whether the blood brain barrier (which restricts passage of substances from the bloodstream to the brain) was vulnerable to high intakes of MSG. It was agreed that, provided the blood brain barrier was intact, passive influx of glutamate into the brain was likely to be insignificant. However, several diseases are known to impair the blood brain barrier and it can’t be ruled out that a single high dose of glutamate may have adverse effects in such cases. At present, there is no data to suggest that raised blood levels of glutamate would translate into high brain glutamate concentrations.
The expert panel regarded a dose of 16,000 mg/kg body weight (or 16 g/kg body weight) to be a safe maximum intake of MSG for adults. It was concluded that current use of glutamate salts (monosodium-L-glutamate and others) as food additives was “harmless for the whole population” and, at low doses, could help to improve appetite in the elderly.
Source: The European Food Information Council (EUFIC)