Characterising the Response to Blueberry Dietary Interventions Aimed at Improving Cognition and Vascular Function

Wang, Yueyue (2021) Characterising the Response to Blueberry Dietary Interventions Aimed at Improving Cognition and Vascular Function. Doctoral thesis, Northumbria University.

Preview

Text (Doctoral thesis) wang.yueyue_phd_17024727.pdf - Submitted Version Download (7MB) | Preview

Abstract

Inter-individual variations exist in response to dietary factors and to the pathophysiologic development of endpoints related to vascular diseases and cognitive impairment. Therefore, the evaluation and characterisation of responses to a dietary intervention targeting vascular and cognitive health is of importance. A series of investigations were set out. Firstly, previous evidence of randomised controlled trials (RCTs) supplementing fruit and targeting vascular and/or cognitive improvement was sought and evaluated by systematic reviews incorporating meta-analyses. Collectively, the reviews have shown that the consumption of berries with dosage ranging from 22 to 45 g powder, 150 to 300 g frozen berry and 100 to 500 ml juice resulted in a 3.68 mmHg reduction on systolic blood pressure and 1.68 mmHg reduction on DBP. A human dietary intervention with 37 participants was performed comparing two forms of blueberry; either whole fresh blueberry (160 g), freeze-dried blueberry powder (20 g) or placebo control (microcrystalline cellulose) in a 1-week single-blinded cross-over RCT in a relatively young outwardly healthy population. There was no significant effect of either blueberry intervention to improve either vascular function or cognition. No significant putative discriminating urinary metabolites between interventions were found using supervised multivariate analysis. The response to the intervention was calculated for each endpoint using percentage change (+ / -%) compared to the baseline. Extensive inter-individual variation was found in vascular health parameters (- 141 % - + 525 %) and cognitive domains (- 114 % - + 96 %) post-interventions, but there was no consistent response following the two interventions between and within participants. Although several discriminatory metabolites were found between responder (RS) and non-responder (NRS) groups it was not possible to identify predictors of response using receiver-operator-curve analysis. To conclude, we did not find a predictive urinary metabolite as a potential biomarker for differentiating between RS and NRS and no consistent individual responses following both blueberry and blueberry powder interventions were found. This is the first blueberry intervention applying quartile division to characterise response in vascular and cognitive endpoints following a specific dietary intervention. The overall approach for defining a metabolic signature of response could be used in the future for tailoring personalised nutritional advice.

Actions (login required)

View Item

Downloads