Browsing by Subject "bioactive"
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Item Dairy- and Soy-Derived Bioactive Peptides and the Renin-Angiotensin-Aldosterone System(2013-05) Munn, MelissaHypertension is a chronic, often asymptomatic, and highly prevalent cardiovascular disorder. Medications prescribed to lower blood pressure in hypertensive individuals are successful but are not without side effects or associated costs that render these agents inconvenient to patients. Furthermore, from a public health standpoint, a proactive approach to preventing or delaying progression into a hypertensive state in at-risk individuals is promising. Researchers have discovered bioactivity in peptides derived from food protein sources and the observed potential for blood pressure lowering effects through ACE inhibition has fueled further interest. This thesis focuses on the potential use of dairy- and soy- derived bioactive peptides in lowering blood pressure through ACE inhibition. Chapter 1 provides an overview of hypertension, including its prevalence, clinical definition, associated risk factors, and potential contributors to its complex pathophysiology, as well as current medications and a brief introduction to the use of bioactive peptides in a functional food. Chapter 2 presents a systematic review of the literature, with a strong emphasis on in vivo animal and human studies regarding the blood pressure lowering potential of dairy- and soy- derived bioactive peptides. Chapter 3 shares the findings of our study on the acute effects of whey- and soy- derived bioactive peptides administered in the form of a cookie to overweight, prehypertensive men and postmenopausal women. Finally, this thesis is concluded with a brief summary provided in Chapter 4.Item The Effects of Green Tea Catechins on Oxidative Stress and Red Wheat on Measures of Oxidative and Nitrosative Stress, Colon Cancer Risk, and Gut Microbiome Composition(2021-09) Fiecke, ChelseyThere have been very few long-term investigations of the in vivo antioxidant effects associated with consumption of green tea catechins, especially in healthy populations. In the first study, we evaluated the in vivo antioxidant effects of 12-month green tea catechin supplementation in healthy, postmenopausal women by measuring urinary excretion of secondary lipid peroxidation products. Green tea catechin supplementation reduced excretion of a nonpolar aldehyde that was identified as nonanal and/or decatrienal. Our results suggest that green tea catechins may exert modest antioxidant effects in healthy populations that do not have elevated oxidative stress.We previously reported that red wheat, the class of wheat used to make yeast bread products, reduced various colon cancer biomarkers. In the second study, we evaluated the chemopreventive effects of red wheat and the aleurone and testa layers by examining morphological markers of colon cancer risk (aberrant crypt foci; ACF), a cancer stem cell marker (doublecortin-like kinase 1; Dclk1), a marker of oxidative and nitrosative stress (3-nitrotyrosine; 3-NT), and gut microbiome composition. The number of medium ACF (3-5 aberrant crypts/ACF) was reduced by consumption of refined red wheat and the aleurone layer. Large ACF (≥ 6 aberrant crypts/ACF) were decreased by the whole and refined red wheat and refined white wheat. Refined red wheat and the aleurone and testa layers reduced 3-NT positivity in aberrant crypts. The microbiome composition differed between diet groups and was driven by altered abundances of Faecalitalea, Lactobacillus, Mucispirillum, and Phascolarctobacterium. Consumption of whole and refined red wheat resulted in enrichment of Faecalitalea and Lactobacillus and depletion of Mucispirillum. These results suggest that the aleurone and testa layers may be partially responsible for the chemoprevention by red wheat, which possibly involves reductions in oxidative/nitrosative stress and modulation of the gut microbiome. In summary, green tea catechins may exert modest antioxidant effects, even under physiological conditions of little oxidative stress. The aleurone and testa layers may play a role in chemoprevention by red wheat, which involves a reduction in oxidative/nitrosative stress and beneficial modulation of gut microbiome composition.