Effect of aspartame and sucrose loading in glutamate-susceptible subjects

It has been postulated that individuals reporting an idiosyncratic symptom response after glutamate ingestion might also experience such symptoms after aspartame ingestion. Such sensitive subjects might have been missed in earlier studies of aspartame. In the present study, six subjects reporting various symptoms after glutamate ingestion, but not after placebo, were administered aspartame (34 mg/kg body weight) or sucrose (1 g/kg body weight) dissolved in orange juice in a randomized, cross-over, double-blind study. No subject reported symptoms typical of a glutamate response after either sucrose or aspartame loading. One subject reported slight nausea approximately 1.5 h after aspartame ingestion, but indicated that the symptoms were not those of a glutamate response. Plasma phenylalanine and aspartate levels were similar to those noted in normal subjects administered identical doses of aspartame. The data indicate no effect of aspartame loading in glutamate-susceptible subjects.