MSG is
generally recognized as safe to eat. A popular belief is that MSG can cause headaches and other feelings of discomfort, but
blinded tests have not provided strong evidence of this. Specifically MSG in the diet does not increase glutamate in the brain or affect brain function. A 1995 report from the
Federation of American Societies for Experimental Biology (FASEB) for the
United States Food and Drug Administration (FDA) concluded that MSG is safe when "eaten at customary levels" and, although a subgroup of otherwise-healthy individuals develop an MSG symptom complex when exposed to 3 g of MSG in the absence of food, MSG as a cause has not been established because the symptom reports are anecdotal. According to the report, no data support any role of glutamate in
chronic disease. High quality evidence has failed to demonstrate a relationship between the MSG symptom complex and actual MSG consumption. No association has been demonstrated, and the few responses were inconsistent. No symptoms were observed when MSG was used in food. Adequately controlling for experimental bias includes a blinded,
placebo-controlled experimental design and administration by capsule, because of the unique aftertaste of glutamates. A study in 2000 tested the reaction of 130 subjects with a reported sensitivity to MSG. Multiple trials were performed, with subjects exhibiting at least two symptoms continuing. Two people out of the 130 responded to all four challenges. Because of the low prevalence, the researchers concluded that a response to MSG was not reproducible. Studies exploring MSG's role in
obesity have yielded mixed results. Although several studies have investigated anecdotal links between MSG and
asthma, current evidence does not support a causal association.
Food Standards Australia New Zealand (FSANZ) MSG technical report concludes, "There is no convincing evidence that MSG is a significant factor in causing systemic reactions resulting in severe illness or mortality. The studies conducted to date on Chinese restaurant syndrome (CRS) have largely failed to demonstrate a causal association with MSG. Symptoms resembling those of CRS may be provoked in a clinical setting in small numbers of individuals by the administration of large doses of MSG without food. However, such effects are neither persistent nor serious and are likely to be attenuated when MSG is consumed with food. In terms of more serious adverse effects such as the triggering of
bronchospasm in asthmatic individuals, the evidence does not indicate that MSG is a significant trigger factor." The FSANZ MSG report says that although no data is available on average MSG consumption in Australia and New Zealand, "data from the United Kingdom indicates an average intake of 590mg/day, with extreme users (97.5th percentile consumers) consuming 2,330mg/day" (Rhodes et al. 1991). In a highly seasoned restaurant meal, intakes as high as 5,000 mg or more may be possible (Yang et al. 1997). When very large doses of MSG (>5 g MSG in a
bolus dose) are ingested, plasma glutamate concentration will significantly increase. However, the concentration typically returns to normal within two hours. In general, foods providing metabolizable
carbohydrates significantly attenuate peak plasma glutamate levels at doses up to 150mg/kg body weight. Two earlier studiesthe 1987 Joint
FAO/
WHO Expert Committee on Food Additives (JECFA) and the 1995
Federation of American Societies for Experimental Biology (FASEB)concluded, "there may be a small number of unstable asthmatics who respond to doses of 1.5–2.5 g of MSG in the absence of food". The FASEB evaluation concluded, "sufficient evidence exists to indicate some individuals may experience manifestations of CRS when exposed to a ≥3 g bolus dose of MSG in the absence of food". ==Production==