Relationship between the Preference for Sake (Japanese rice wine) and the Movements of Metabolic Parameters Coinciding with Sake Intake

Abstract

Selection of foods by animals largely depends on their physiological condition. In this paper, we reported how physiological changes in rats after ingestion of sake (Japanese rice wine) affected their preference for different kinds of sake. Rats could discriminate among various kinds of sakes in a two-bottle choice test, even after adjustment of the glucose concentration or alcohol concentration of the sake, suggesting that the choice of a sake by animals was based on more than one ingredient. To identify effect of a rat’s physiological condition on the selection of sake, we monitored the levels of blood glucose, nonesterified fatty acids (NEFA), and ketone bodies in serum in mice after forced intragastric ingestion of sake that had previously been offered to the rats in a two-bottle choice test. Blood glucose levels in mice were not different between the rats fed the palatable and unpalatable sakes, and the NEFA level and ketone level were high in rats fed the unpalatable sake. To further clarify the relationship between physiological condition and preference for sake, rats were offered eight kinds of Junmai-syu, which is made with only rice and no sub-ingredient. Rats could still discriminate among Junmai-syu. Furthermore, with two exceptions, the preference for a sake was significantly correlated with the ketone level. The order in the ratio of blood insulin level to blood glucagon level, which is an indicator of metabolism, was correlated with the order in preference to sake. These results suggest that some physiological factors besides oral stimulation also are important factors in the selection of a sake.