Abstract/Summary

Scientific evidence suggests that wild blueberry (WBB) polyphenols elicit benefit for cognitive function in humans. In this thesis, the effects of acute WBB consumption will be explored in participants across different age groups. The aim is to understand how cognitive function is affected in the immediate period post-dosing and to examine how different age groups show sensitivity to WBB in different cognitive domains. Whilst acute effects are interesting, repeated daily dosing is required to have long-term impact and to delay cognitive decline. To explore this further, the consumption of WBB for three months will be explored in a healthy ageing population. The aim of this is to further our understanding related to the cognitive effects of chronic WBB consumption, and to understand which cognitive domains show sensitivity following chronic consumption. This thesis will also investigate how vascular and cerebral blood flow parameters are affected following acute consumption across the life-course and following chronic consumption in healthy older adults. The aim of this is to elucidate the mechanisms of action behind observed cognitive effects. Furthermore, the assessment of polyphenol metabolites in plasma and urinary samples will be measured to help provide evidence into the bioavailability of metabolites in the human body. Lastly, recent investigations are beginning to demonstrate that polyphenols impact the gut microbiome. To explore this further, the microbial composition following three months consumption of WBB in healthy older adults will be assessed Benefits for episodic memory, visuo-spatial working memory, and executive function were found following acute consumption across different age groups. Secondly, chronic WBB consumption demonstrated improvements for episodic memory and executive function in healthy older adults. No treatment-related effects were observed for parameters of cerebral blood flow in either study. Both acute and chronic WBB consumption revealed increases in the level of metabolites, when compared to placebo consumption. However, analyses of microbiome revealed no significant differences in alpha or beta diversity following WBB consumption. As a whole, the results observed from this thesis support the current evidence for WBB and cognitive function. The implications of these findings are of great importance and may be translated into our everyday lives as a way of enhancing cognitive function.