The Positive Modulation Effect of a 6-Week Consumption of an Anthocyanin-Rich Mulberry Milk on Working Memory, Cholinergic, and Monoaminergic Functions in Healthy Working-Age Adults

Due to the increase of stress-related memory impairment accompanying with the COVID-19 pandemic and financial crisis, the prevention of cognitive decline induced by stress has gained much attention. Based on the evidence that an anthocyanin-rich mulberry milk demonstrated the cognitive enhancing effect, we hypothesized that it should be able to enhance memory in working-age volunteers who are exposed to working stress. This study is an open-label, two-arm randomized study. Both men and women volunteers at age between 18 and 60 years old were randomly assigned to consume the tested product either 1 or 2 servings daily for 6 weeks. All subjects were assessed for cortisol, acetylcholinesterase (AChE), monoamine oxidase (MAO), monoamine oxidase type A (MAO-A), and monoamine oxidase type B (MAO-B) in saliva, and their working memory was determined both at baseline and at a 6-week period. The results showed that the working memory of subjects in both groups was enhanced at the end of the study period together with the reduction of saliva cortisol. The suppression of AChE, MAO, and MAO-A was also observed in subjects who consumed the tested product 2 servings daily. Therefore, we suggest the memory enhancing effect of an anthocyanin-rich mulberry milk. The possible mechanism may occur primarily via the suppression of cortisol. In addition, the high dose of mulberry milk also suppresses AChE, MAO, and MAO-A.