Sensory cues for dietary fat: Implications for macronutrient preferences

We have shown that free fatty acids, particularly the essential, or cis-polyunsaturated, fatty acids inhibit delayed rectifying K+ channels in a variety of tissues that may play a role in fat recognition and ultimately in the control and regulation of fat intake. The inhibition of DRK channels in general would be predicted to lead to an overall increase in cell excitability since the primary role of these channels is in the repolarization of cells following activity. These channels also have been shown to play a role in stimulus transduction directly in taste cells, where they are apparently the target for inhibition, directly or indirectly, by a number of different taste stimuli, including some bitter, sweet and acidic tastants(7,9). The ability of fatty acids generated via lingual or gastric lipases to activate cells in a variety of tissues via an inhibition of DRK channels may represent a universal mechanism by which the body recognizes dietary fat. Moreover, our finding showing the inverse correlation between peripheral (i.e gustatory) fatty acid responsiveness and dietary fat preferences may be indicative of a role of these signaling pathway in a negative feedback pathway contributing to the control of ingestive behavior. Obviously, this remains speculative and will require specific experiments aimed at testing the link directly between these putative fat transduction pathways and their role in helping shape macronutrient preferences.