The Select Committee notes that the new information on long-term oral administration of monosodium glutamate (MSG) is the diet to varios animal species has revealed no adverse effects, while data showing neuropathological lesions in neonatal animals resulting from subcutaneous or forced oral dosing of MSG has thus far been confirmed only in rodents. The administration of protein or carbohydrate products concurrently with MSG has been shown to lower plasma glutamate levels, and in two recent studies, to reduce the incidence of hypothalamic lesions in mice. In pregnant monkeys, glutamate does not appear to readily cross the placental barrier. From comparisons of plasma glutamate levels, healthy term and premature infants have already developed the capability to metabolize glutamates. Ingestion of MSG solutions has been demostrated to cause transient clinical symptoms resembling those of "Chinese Restaurant Syndrome" and there is evidence that some individuals may respond to relatively small doses. Similar symptoms can be evoked by certain other food substances. The use of MSG in restaurant and/or home-prepared foods not fall within the purview of the Select Committee since it is limited in its considerations to the use of glutamates as ingredients of processed foods. According to industry sources, MGS is not added to infant and junior foods. Because, however, a proportion of the consuming public may be sensitive acute responders, even though the unpleasant symptoms are transient, the Selected Committee believes there should be some constraint placed on the addition of MSG to processed foods.
In light of the foregoing studies on the biological effects of monosodium glutamate and the information considered in its previous report on glutamates, the Select Committee concludes that: There is no evidence in the available information on L-glutamic acid, L-glutamic acid hydrochloride, monosodium L-glutamate, monoammonium L-glutamate, and monopotassium L-glutamate that demonstrates, or suggests reasonable grounds to suspects, a hazard to the public when they are used at levels that are now current and in the manner now practices. However, it is not possible to determine, without additional data, whether a significant increase in consumption would constitute a dietary hazard.