Effects of omega-3 fatty acids on working memory in rats with increased sugar intake

•Effects of omega-3 fatty acids on working memory in rats with increased sugar intake were studied.•Detrimental effects of omega-3 fatty acid deprivation on working memory were found.•Interaction of dietary components should be considered when studying effects of modified diets. The “Western” diet, with its high sugar content and low levels of omega-3 fatty acids (n-3), has been linked to various cognitive deficits and mental disorders in animal models and humans. We have examined whether a dietary deficiency in n-3 in combination with increased sugar consumption affects working memory in rats. Wistar rats were bred and fed a high-sugar diet over several generations. The animals were randomly assigned to two groups: a group receiving physiologically adequate amounts of n-3 and a group fed an n-3-deficient diet. Thirty-one male, fourth generation rats were tested in a radial arm maze in order to assess working memory performance. Compared to rats receiving a diet with sufficient n-3, the n-3-deprived animals erred more frequently on working memory tasks, indicating that n-3 reduction in rats on a sugar-rich diet may have negative effects on working memory additional to those associated with high sugar consumption.