Phytochemicals to optimize cognitive function for military mission-readiness: a systematic review and recommendations for the field

Context: Optimizing cognitive performance and preventing cognitive impairments that result from exposure to high-stress situations are important to ensure mission-readiness for military personnel. Objective: This systematic review assesses the quality of the evidence for plant-based foods and beverages, or their phytochemical constituents, across various outcomes related to cognitive function in healthy adult populations to develop research recommendations for the military. Data Sources: PubMed, CINAHL, Embase, PsycInfo, and the Cochrane Library were searched. Study Selection: Peer-reviewed randomized controlled trials published in the English language were eligible. Data Extraction: Twenty-five trials were included and assessed for methodological quality, and descriptive data were extracted. Data Synthesis: The acceptable (n = 16) to high-quality (n = 4) studies produced either no statistically significant effect or mixed results for enhancing cognitive function. Conclusions: The evidence suggested that healthy populations do not experience significant changes in cognitive performance when consuming soy- and non-soy-sourced isoflavones or cocoa. Heterogeneity among other interventions precluded reaching formal conclusions surrounding the evidence. Research recommendations are offered, including conducting more studies on the effect of plant-based interventions on populations reflective of military populations when exposed to military-like situations.