Experience-induced changes in taste identification of monosodium glutamate.

Taste sensitivity for a given subject generally has been thought to be genetically determined and not plastic. Yet experience-inducible changes in human taste and olfactory sensitivities have been reported. To test a taste induction hypothesis, we exposed 17 Americans/Europeans to monosodium glutamate (MSG) in food and then compared their ability to identify MSG taste with that of 2 control groups (18 Americans/Europeans without MSG exposure and 18 Japanese). When tested on Day 11 or 12, the Americans/Europeans exposed to MSG were able to identify MSG at significantly lower concentrations than the Americans/Europeans without MSG exposure. Moreover, Japanese subjects who had prior extensive experience with MSG in Japanese food were able to identify MSG at significantly lower concentrations than the two American/European groups. The differences in identification ability between the two American/European groups challenge the notion of taste sensitivity as stable over time and support the hypothesis of an experience-inducible component in human taste.