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Title: Determination of the impact of wholegrain on intestinal and systemic markers of human health and disease
Author: Connolly, Michael Leo
ISNI:       0000 0004 2716 8284
Awarding Body: University of Reading
Current Institution: University of Reading
Date of Award: 2011
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Epidemiological studies have reported an inverse association between wholegrain and risk of cardiovascular disease, diabetes, obesity and some forms of cancer. However, the mechanisms of wholegrain protection against these diseases are poorly understood. Two characteristics of wholegrain that may impact on health are the glycaemic index (GI) and potential to modulate the colonic microbiota. A diverse population of microorganisms resides in our colon, known as the gut microbiota. These bacteria may play an important role in these diet-associated diseases and the diet microbe interaction is a topic of specific interest. Consumption of most wholegrains results in a low insulin response (low glycaemic index (GI)). Processing often leads to detrimental effects on this beneficial attribute and may in turn also alter potential to modulate the gut microbiota. A number of in vitro experiments were performed to investigate how processing and cooking of oat, wheat and wholegrain pasta impact on the ability of these foodstuffs to beneficially modulate the gut microbiota. Processing and cooking impacted negatively on favourable bacteria and short chain fatty acid profiles in the in vitro faecal microbiota fermentations. Using in vivo and in vitro methods, a low glycaemic index, potentially prebiotic whole grain oat (WGO) breakfast cereal was identified. Effects on markers of cardio-metabolic risk and colonic microbiota after 6-week daily consumption of WGO were explored in subjects, who had either or both, slightly elevated levels of fasting glucose and total cholesterol. Numbers of total bacteria, Bifidobacterium and Lactobacillus significantly increased, while a significant decrease in total cholesterol was observed after the WGO compared with a control cereal. This thesis shows that processing of wholegrain adversely affects GI and reduces their potential as prebiotic food. Furthermore, consumption of a low GI, prebiotic WGO cereal was observed to successfully modulated the gut microbiota towards a favorable composition and resulted in hypocholesterolaemic effects. This supports the hypothesis that microbiota modulation may confer cardio- metabolic health benefit.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available