Cerebral gustatory activation in response to free fatty acids using gustatory evoked potentials in humans

There is some evidence of specific oro-detection of FFAs in rodents and humans. The aim of this study was to record gustatory evoked potentials (GEPs) in response to FFA solutions and to compare GEPs in response to linoleic acid solution with GEPs obtained after stimulation with sweet and salty tastants. Eighteen healthy men were randomly stimulated with fatty (linoleic acid), sweet (sucrose), and salty (NaCl) solutions at two concentrations in the first experiment. Control recordings (n = 14) were obtained during stimulation by a paraffin oil mixture without FFA or by water. In the second experiment, 28 men were randomly stimulated with five FFA solutions and a paraffin emulsion. GEPs were recorded with electroencephalographic electrodes at Cz, Fz, and Pz. GEPs were observed in response to FFA in all participants. GEP characteristics did not differ according to the quality and the concentration of the solutions in the first experiment and according to the FFA in the second experiment. This study describes for the first time GEPs in response to FFA and demonstrates that the presence of FFA in the mouth triggers an activation of the gustatory cortex. These data reinforce the concept that fat taste could be the sixth primary taste.