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Title: Polyphenol intake, dietary patterns and psychological status
Author: Rooney, C.
Awarding Body: Queen's University Belfast
Current Institution: Queen's University Belfast
Date of Award: 2014
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Increasing evidence has suggested that dietary consumption may have the potential to influence mental health. However, few experimental studies have examined the effect of polyphenol-rich foods on psychological health. Furthermore, minimal studies exist on consumer attitudes towards polyphenol-rich foods. Thus, the main aims of this thesis were to investigate the effect of polyphenol-rich foods (FV, berries and dark chocolate) on psychological health, and to examine the behaviours, attitudes and knowledge consumers have with regards to the consumption of these foods. Firstly, results from a systematic review suggested that current evidence surrounding fruit and vegetables (FV) and psychological well-being is inconclusive. The review highlighted the need for future randomised controlled trials to investigate the relationship further. Secondly, a randomised controlled trial (PPhIT) showed mixed findings with regards to the effect of an eight week polyphenol-rich dietary pattern (FV, berries and dark chocolate) on psychological health. Improvements were observed for certain outcomes, including depressed mood and mental health (quality of life), but not for others (e.g. self-esteem and body-image). The dietary intervention led to significant increases in nutritional biomarkers, indicating good participant compliance. Overall, participants showed favourable attitudes towards the polyphenol-rich diet. Whilst a number of barriers towards the study diet foods were detected at baseline, the intervention significantly reduced some of these (e.g. ease, willingness, awareness). Similarly, a second ReT (n=30 adults), highlighted various barriers and facilitators towards FV consumption. However, in contrast to PPhIT, the four week intervention did not significantly modify these. This study also detected a lack of knowledge regarding what constitutes a portion of FV. The inconsistent findings from this thesis surrounding the effect of polyphenol-rich foods on psychological health suggest further research is warranted. Future research on the capacity for dietary interventions to reduce barriers towards polyphenol-rich foods may also be of value.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available