The Effect of High-Fructose Corn syrup on Ethanol Taking, Seeking, and Palatability in Rats
Many alcoholic beverages contain sweeteners, such as high-fructose corn syrup (HFCS), which has been implicated in increasing alcohol consumption and encouraging hazardous drinking patterns. Therefore, four experiments were designed to investigate whether the addition of HFCS to an ethanol (EtOH) solution could alter its intake, hedonic taste, and sensitivity to food deprivation stress in Sprague Dawley rats. Experiments 1 and 2 revealed that HFCS caused a robust increase in EtOH intake during operant intraoral self-administration (IO SA), however an equally palatable, yet non-caloric sweetener (saccharin) could not replicate this effect. This suggests the caloric value of a sweetener mediates the effect of sweeteners on EtOH intake. Experiments 3 and 4 revealed food deprivation stress increased EtOH consumption during resumption following extinction, but only when HFCS was added to the solution. The palatability of 10% EtOH and 25% HFCS was also monitored across IO SA, and under conditions of food deprivation stress. It was found that the palatability of 10% EtOH and 25% HFCS increased following acquisition. More interestingly, food deprivation stress only increased HFCS palatability. Thus, it could be the heightened palatability of HFCS under stressful conditions that contributes to increased operant responding for solutions containing HFCS during resumption in rats. These results have implications for the use of highly palatable and caloric sweeteners in EtOH beverages because of the impact they may have on excessive EtOH intake.