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ABSTRACT
Journal of Nutrition. 2000;130:1049S-1052S.
Supplement
The Safety Evaluation of Monosodium Glutamate
Ronald Walker and John R. Lupien*
School of Biological Sciences, University of Surrey, Guildford GU2 5XH, Surrey, UK
and *Food and Nutrition Division, FAO, 00100 Roma, Italy
L-Glutamic acid and its ammonium, calcium, monosodium and potassium
salts were evaluated by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) in 1988.
The Committee noted that
intestinal and hepatic metabolism results in elevation of levels in systemic circulation
only after extremely high doses given by gavage (>30mg/kg body
weight). Ingestion of monosodium glutamate (MSG) was not associated
with elevated levels in maternal milk, and glutamate did not readily pass
the placental barrier. Human infants metabolized glutamate similarly
to adults. Conventional toxicity studies using dietary administration
of MSG in several species did not reveal any specific toxic or carcinogenic effects nor were
there any adverse outcomes in reproduction and teratology studies.
Attention was paid to central nervous system lesions produced in several
species after parenteral administration of MSG or as a consequence of very high
doses by gavage. Comparative studies indicated that the neonatal mouse was most
sensitive to neuronal injury; older animals and other species (including primates) were
less so. Blood levels of glutamate associated with lesions of
the hypothalamus in the neonatal mouse were not approached in humans even after bolus doses
of 10 g MSG in drinking water. Because human studies failed to confirm an involvement
of MSG in "Chinese Restaurant Syndrome" or other idiosyncratic intolerance, the JECFA
allocated an "acceptable daily intake (ADI) not specified" to
glutamic acid and its salts. No additional risk to infants was
indicated. The Scientific Committee for Food (SCF) of the European Commission reached
a similar evaluation in 1991. The conclusions of a subsequent review by
the Federation of American Societies for Experimental Biology (FASEB) and
the Federal Drug Administration (FDA) did not discount the
existence of a sensitive subpopulation but otherwise concurred with the
safety evaluation of JECFA and the SCF.
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