Saudi Cultural Missions Theses & Dissertations
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Item Restricted Enhancing iron bioavailability from cereals as a strategy to reduce iron deficiency: in vitro digestion studies and a randomised control trial in UK females(Saudi Digital Library, 2023-12-24) Arafsha, Sarah Mohammed; Sharp, PaulBackground and hypothesis: Iron deficiency (ID) is the most common nutritional deficiency worldwide, and progress towards prevention of this disorder is slow. Plant foods are important sources of minerals in the United Kingdom. For example, 50% of iron is provided by cereals and a further 15% by vegetables. However, physical encapsulation within plant cells and the presence of absorption inhibitors such as phytic acid limit the availability of iron from plants for absorption in the human small intestine. The overall hypothesis for this project is physical disruption of wheat flour cell walls will increase the release of iron (i.e. the bioaccessibility) from foods during digestion and thereby enhance the bioavailability of iron from wheat-based foods. If successful, this change in milling of flour may provide a strategy to reduce the incidence of ID. Materials and methods: Studies were carried out using wheat flour produced by either standard milling or by micro-milling to reduce flour particle size. Mineral content of foods were determined by ICP-OES. The effects of cooking (boiling and baking), digestive enzymes, and pH on iron bioaccessibility from wheat-based foods following in vitro digestion was measured by ICP-OES. Food digests were applied to intestinal Caco-2 cells and iron bioavailability was assessed using ICP-MS. A human study was also carried out to assess the bioavailability of iron wheat breads made from standard and micronized flour. Results and conclusion: Micro-milling reduced flour particle size by 3-times. Foods made from micronized flour had higher iron bioavailability. This was particularly evident following gastric digestion when pH was low. In summary, the results suggest that micro-milling may increase iron bioaccessibility and bioavailability of iron from wheat flour. If endogenous iron in wheat-based foods was more bioavailable this might decrease the incidence of ID seen in some population groups in the UK.14 0Item Restricted Determination of the Urinary Components of Nitrogen Excretion in Premature Infants(Saudi Digital Library, 2017) Arafsha, Sarah Mohammed; Eaton, SimonBackground: Although several researchers have conducted nitrogen balance studies in premature infants in the past, very few have partitioned urinary nitrogen into its components. Determination of the urinary components of nitrogen excretion in premature infants will help in evaluating the ideal protein requirements for infant growth. Aims: To investigate the components of nitrogen excretion, including urea, protein, creatinine, uric acid and ammonia in premature infants. To Identify the unknown nitrogen compounds which account for the TUN. Findings from the study could have important implications for infant growth. Methods: Thirty-nine urine samples from healthy premature infants. Total urinary nitrogen of the samples was measured by a chemiluminescent nitrogen analyser. Protein, urea, uric acid, creatinine, nitrite and nitrate levels were measured using different assays. Urine samples were fractionated (e.g. acid soluble, acid insoluble, hydrophilic, hydrophobic fractions) and the nitrogen content of each fraction measured in order to elucidate the components of nitrogen excretion in urine. Results: the average UUN/ TUN ratio in preterm infants is 48.8%. Therefore, UUN cannot be used by its own to measure TUN. The average UUN/TUN ratio varies among different groups and across all samples from the same infant. By using HPLC I attempted to identify the components by comparing the retention times or peaks of samples with those of known compound. For proteins and pellets, the p value showed a significant relationship, but the r2 value did not show a strong correlation (r2 = 0.2660, p = 0.0042). Conclusion: All the data collected in the study indicates that UUN/TUN ratio is low and the ratio of UUN/TUN between samples is variable. Therefore, UUN on its own is not an accurate measurement for TUN in healthy premature infants. Underdetermined nitrogen components remain an area for further investigation.21 0