Effects of Freeze-Dried Whole Grapes on Cognitive Performance in Postmenopausal Women

Abstract

Objectives Neuropsychological and emotional symptoms associated with menopause are a major concern of women. The present study explored whether daily consumption of freeze-dried whole grape powder (GP) would improve cognitive abilities, and emotional symptoms. Methods In this double-blind, placebo-controlled trial, 40 postmenopausal women (1 to 5 years past menopause), not on hormone therapy, were randomly assigned to consume either 46 g of GP or grape placebo powder for 12 weeks. Subjective memory, objective cognitive performance, and depression and anxiety symptoms were assessed at baseline and after the 12-week GP supplementation. A mixed-effects model (PROC MIXED) was used to examine the effects of time, group, and the interaction between time and group. P < 0.05 was considered statistically significant. Results Thirty-two women successfully completed the study. There was a significant time x group interaction effect observed for movement time (P < 0.05) and reaction time (P < 0.05) and a borderline significant time x group interaction effect observed for spatial working memory total error (P = 0.07). In addition, a significant time effect was found for memory strategy (P < 0.05) and a borderline significant time effect observed for rapid visual processing A′ (P = 0.09), but without significant impacts of time and time x group interaction. Neither GP nor placebo powder significantly influenced the performance of digit span, paired associates learning task, subjective memory ability, or contentment with memory. There were no remarkable effects on depression and anxiety symptoms. Conclusions Our findings demonstrated that the 12-week supplementation of GP enhanced movement time and reaction time performance by 5% and 8%, respectively in comparison with the placebo. Larger follow-up studies are needed to ensure the validity of these findings. Funding Sources This research was funded by the California Table Grape Commission. Funders had no role in the study design, data collection, data analysis or interpretation, or writing of the abstract.