In addition to its established role in bone health, vitamin D (2S(OH)D) may also have a role in modulating immune function and early life development. Despite recent advances, there is a lack of consensus with regards to the optimal vitamin D cut-offs for multiple health outcomes and this uncertainty is further compounded by the wide measurement variability for the vitamin. Consequently, the work described in this thesis aimed to explore these areas of controversy. Using data from ongoing studies at the University of Ulster, a comparison study (n 131), of vitamin D status in the two most widely used methods (liquid chromatography mass spectrometry (LC-MS/MS) and enzyme immunoassay (ELISA)) of measurement was undertaken. Significant variation in definition of status was observed, with overestimation of vitamin D concentrations by ELISA >2S% compared to LC-MS/MS. In a second study, using LC-MS IMS, the vitamin D status and markers of bone health of a sample of older Irish adults (n 1936) form the Trinity, Ulster Department of Agriculture (TUDA) study was assessed. A total of 16% were vitamin D deficient «2Snmolll) and 42% were deemed to be insufficient (2S-S0nmolll). These levels of nonoptimal vitamin D concentrations were coupled with high rates of impaired bone health (31 % classified as osteopenic and 18% osteoporotic from BMD measures). A higher prevalence of impaired bone health and vitamin D inadequacy was observed in females compared to males while individuals who were vitamin D deficient or insufficient were significantly more likely to be osteoporotic than those who were sufficient (>SO nmol/l). These data provide additional evidence to support the recent 10M recommendation of a 2S(OH)D concentration of 50 nmol/l for optimal bone health. In a third study, the association between vitamin D status, immune markers of inflammation and the ratio of pro: anti-cytokines was investigated in a sub-sample of TUDA participants (n 998). Vitamin D was significantly correlated with pro-inflammatory markers and a 25(OH)D concentration >75nmol was associated with an improved inflammatory (profile as determined by the pro:anti cytokine ratio) compared to individuals with a 25(OH)D status <25 or 25-75nmol/l. In a fourth study, vitamin D status was assessed within a sample (n 260) of pregnant women from a sunny equatorial country (5degS) (Seychelles). Maternal vitamin D status was observed to be >75nmol/l through all sample periods of pregnancy and was significantly associated with higher birth weight and length with no apparent upper limit of effect. These results demonstrate the importance of optimal vitamin D status during pregnancy and the need for adequate dietary recommendations in order to achieve this level within far latitude populations that are exposed to low UVB sun light. In conclusion, the results within the current thesis suggest concentrations of vitamin D greater than recently recommended cut-offs for bone health (50nmol/l) are associated with extra-skeletal health benefits. Furthermore, consideration needs to be given to the current vitamin D dietary recommendations within the UK and Ireland in order to address the high level of deficiency observed in the older adult population and to achieve the optimal vitamin D concentration in terms of benefits for bone health, immune function and neonatal health outcomes for the whole population

Cardiovascular disease (CVD) is the most common cause of death globally; yet, its pathogenesis and early development are poorly understood. Atherosclerosis begins early in life and is associated with CVD risk factors including diet. This thesis investigated associations between diet and atherosclerosis development. Participants in an RCT investigating effects of supplementation with DHA – an n- 3 fatty acid – provided a convenience sample for this epidemiological dietary study. The primary RCT outcome was brachial artery endothelial function measured using vascular ultrasound (FMD). Secondary outcomes were conventional CVD risk factors. A food frequency questionnaire (FFQ) was used to derive dietary patterns and relationships between dietary patterns and outcomes were investigated. A FFQ for assessment of n-3 LC PUFA was designed. Red cell fatty acids were used to validate the FFQ and investigate relationships of n-3 fatty acids with atherosclerosis development. A healthy dietary pattern was associated with lower carotid artery intima media thickness in women in the highest compared with the lowest quintile for this dietary pattern score (mean difference: -0.07mm, 95% CI: 07 -0.1, -0.03, P = 0.002). This pattern was also associated with lower CVD risk. Dietary patterns were not directly related to FMD. Higher DHA status was associated with lower FMD in women (mean difference in absolute amounts: -0.08 mm, 95% CI: -0.1, 0.03; P = 0.001). FMD was lower in DHA supplemented compared to control groups (mean difference in absolute amounts: -0.03 mm; 95% CI: -0.005 to -0.06 mm; P = 0.02). In secondary analysis this effect was confined to men. Triglyceride (mean difference: -28%, 95% CI: -40% to -15%; P<0.0001) and VLDL concentration were significantly lower in DHA supplemented individuals compared to controls. Findings suggest that diet protects against atherosclerosis development via reductions in conventional CVD risk factors.

The food situation in Saudi Arabia has markedly changed during the last two decades. A nutrition transition is taking place in the country in which traditional foods are being replaced by fast foods high in fat, sugar, and salt. Since one important modifiable risk factor of cardiovascular disease (CVD) is dietary intake is important to monitor these changes in order to estimate the potential effects of this dietary transition as CVD risk. Saudi Arabia has a wide geographical variation with its two major cities located in contrasting regions where local food availability is very different. Therefore, this study was designed to investigate dietary intake in two samples of adults living in different geographic locations (coastal and internal areas) of Saudi Arabia and also, those living abroad (in this case, in Newcastle, UK). 308 Saudi men and women aged 18 - 65 years were recruited from King Abdul-Aziz University, in the coastal city of Jeddah (50 men, 50 women), Umm Al Qura University, in the inland city of Makkah (73 men, 56 women) and those living abroad in Newcastle, UK (32 men, 47 women). All participants completed detailed three consecutive day food records and an assessment questionnaire that included question on lifestyle practices and socioeconomic status. Height and weight, waist and hip circumference were measured in order to calculate body mass index (kg/m2), and waist/hip ratio. The mean (SD) ages of women and men were 31.1 years (7.35) and 32.2 years (8.27), respectively. BMI was lower in men and women from the coastal region 25.1 (2.76) than the inland region 26.3 (3.21), and for Saudis in Newcastle it was 25.6 (4.36) (P < 0.05). Smoking was more prevalent in the internal area (63%) than coastal area (34%) and (26%) in Saudi immigrants (P < 0.001). Men were more physically active than women in three cities. Dietary intake data across the three locations demonstrate that subjects from the coastal city had a significantly lower energy intake and SFA intake but higher intakes of MUFA and PUFA, fibre, selenium and vitamin A (P < 0.05). In contrast they ate significantly less carbohydrates, calcium, magnesium, sodium, potassium and zinc (P < 0.05). Altogether, the diet of internal city resembled the samples in Newcastle more than the coastal city diet because the levels of key nutrient and food intakes, such as energy, SFA, carbohydrates, calcium, magnesium, potassium and vitamin A, were similar. On the other hand, MUFA and PUFA intakes were different between the three cities (P < 0.001). Fatty acids intakes differed markedly between locations, with the coastal diet higher in omega 3 fatty acids 1.3 vs. 0.37 vs. 0.78 g/day compared with internal diet and Saudi immigrants diet, respectively (P < 0.001), while internal area had highest in trans fatty acids intake (P < 0.001). It is concluded that, the results indicate that the prevalence of CVD risk factors in Saudi adults seems to be high. Food intake was statistically significantly correlated with CVD risk factors for the whole study population. There were differences between each location: people living close to the coastal area consumed more fish and therefore more total omega 3 fatty acids relative to individuals living in the internal areas of Saudi Arabia, in Makkah. This higher intake of total omega 3 fatty acids by individuals living in the coastal city of Jeddah may be one of the reasons for the city’s lower rates of CVD. Nutrition education among internal residents is needed for improving diet quality and for increasing consumption of omega 3 fatty acids.

Foods targeting gut health (probiotics and/or prebiotics) constitute one of the largest and fastest growing sectors within functional foods. The majority of probiotic products in the market are dairy-based. The increasing demands for this health enhancing products have created opportunities for the development of non-dairy probiotic formulations. Previous work has demonstrated that cereals and cereal fractions are good substrates for the proliferation of lactobacilli and bifidobacteria strains (main probiotic microorganisms). Cereals could be used to design novel cereal-based fermented beverages with probiotic characteristics if these have acceptable physicochemical and organoleptic characteristics. The purpose of this work is to study the flavour development of cereal substrates fermented with human derived lactic acid bacteria. The production of volatile and non-volatile flavour compounds, physicochemical and sensory properties will be evaluated in wheat, barley, malt and oat media individually inoculated with Lactobacillus acidophilus NCIMB8821, Lactobacillus plantarum NCIMB8826, and Lactobacillus reuteri NCIMB 11951. A considerable amount of development work was done to optimize the analytical techniques for the determination of volatiles, and a broad range of those were detected in fermented and unfermented cereal substrates. Volatile compounds that had been reported to exhibit flavour attributes in fermented products were selected. The evaluation of acetaldehyde, diacetyl, ethyl acetate, acetone and ethanol was carried out through the application of a headspace gas chromatography method (HSGC). It was observed that the values of these volatiles were specific to each substrate tested and their concentrations varied during the fermentation process. Acetaldehyde, which had been reported as an impact flavour compound in other fermented products, was detected in concentrations above its threshold in some of the cereal beverages. Diacetyl was only detected in products formulated with malt substrate. Lactic acid concentrations where always greater than the values of acetic acid which could be a positive outcome since acetic acid has flavour attributes associated with "vinegar" while lactic acid has been described to exhibit a more "mild acidic" taste. During the sensory evaluation it was found that those products formulated with L. plantarum had a greater acceptance. After correlating the chemical, physicochemical and sensory properties it was observed that malt fermented beverages had higher values of most of the chemical components and physicochemical properties evaluated. Our results showed that the acceptance of those products formulated with L. plantarum was characterized by having greater concentrations of the volatile acetaldehyde and pH values above 3.5. Of the formulations tested L. plantarum is the most preferred lactobacilli strain in the malt and barley media. The use of mixed cultures could also be considered in future work and shelf life studies should also be performed.

Groups of the UK population have poor vitamin D status, particularly those with low sun exposure and/or poor dietary intake. This study looked at the impact of fortifying more foods with vitamin D in the UK on population vitamin D intakes and status. It included: • A systematic review, which found that consumption of a wide variety of foods (including milk, orange juice and bread) fortified with vitamin D can improve vitamin D status; and that national schemes have been effective at improving status of some, but not all groups of the target population. • An update of the vitamin D content of fortified foods and supplements within the National Diet and Nutrition Survey (NONS) Nutrient Databank, which increased current population vitamin D intakes by 3%. Consideration of a standard level of 'overage' applied during fortification increased population intakes by a further 3%. • A computer-based data processing exercise to simulate the effect of fortifying flour and milk with vitamin D using NONS data. At 10µg vitamin D per 100g flour, the proportion of 'at risk' groups with vitamin D intakes below the UK Reference Nutrient Intake (RNI) was reduced from a current level of 97% to 53%, without anyone exceeding the European Tolerable Upper Intake Level (UL) for vitamin D. Fortification of flour at this level improved intakes across all socio-economic groups and was found to be more effective than fortification of milk, as well as simultaneous fortification of milk and flour. Fortification therefore provides an opportunity for improving vitamin 0 intakes and status in the UK However, there remains much uncertainty surrounding vitamin D, in particular around intake and status levels required for optimum health and the analytical methods used to determine these. Further research is therefore recommended prior to introducing a national scheme to fortify with vitamin D in the UK.

Observational studies suggest there is an independent relationship between obesity and chronic kidney disease (CKD). The mechanisms of this relationship remain unclear, although contributing factors include inflammation, insulin resistance, and hypertension. The aim of this thesis was to investigate the relationship between obesity and CKD using a range of study methodologies, deploying established and novel weight loss interventions. Participation in a structured multidisciplinary weight loss intervention may be associated with a longer event-free period for the combined outcome of all cause mortality and cardiovascular morbidity in obese patients with CKD, compared to those referred to, but not participating in the intervention. Estimated kidney function significantly underpredicted measured glomerular filtration rate in obese patients with stages 3-4 CKD. Laparoscopic sleeve gastrectomy weight loss surgery was effective for weight loss in obese patients with CKD, although, in the small samples studied in this thesis, the risk for complications and adverse events, including mortality, may be greater in patients undergoing haemodialysis than in obese patients with earlier stages of CKD. Sleeve gastrectomy resulted in significantly greater weight loss than best medical care in obese patients with CKD, and may improve kidney function by reducing hyperfiltration. Quality of life, adiponectin and insulin resistance improved following sleeve gastrectomy, compared to best medical care in obese patients with moderate CKD. The odds ratio for CKD increases with overweight and obesity in the Health Survey for England 2010, compared to healthy weight participants. Evidence of a relationship between obesity and risk of CKD in a national sample of the United Kingdom population confirms the perceived need for safe and effective weight loss interventions for obese patients with CKD in a national context.

Out-of-home (OH) eating has been identified as one of the many contributing factors to obesity because of its increasing association with higher energy intakes. In Irish children in 2003,77% ate OH with their families at least once per week. Therefore, the aim of this thesis was to assess the role and impact of OH eating on children's diets to inform future measures that could support healthier OH food choices. National nutrition and health related policies (/155) were reviewed for guidelines on providing healthier OH food for children in the private sector. Few policies considered the private sector and those that did predominantly highlighted the impliance of providing nutrition information for consumers. Analysis of children' s menus (/1106) in the private sector revealed a paucity of healthier items for children, however this may reflect consumer demand. Subsequent discussions with parents (24 focus groups) and children (48 friendship pairs) showed that eating in the private sector was mainly viewed as a treat for families and nutritional quality was not a priority in food choice decisions. Parents also provided insight into facilitators that may improve the nutritional quality of food targeted specifically at children. Primary schools (/120) were more likely than post-primary schools (n10; P<O.OO 1) to meet the nutrient based standards (NBS) but no school met all of the NBS. This thesis has identified a number of complex challenges relating to the provision of healthier OH food choices for children in both the public and private sectors. Future initiatives aimed at the private sector should take cognisance of parents' and children's perspectives as well as the caterers ' perspective. In the public sector, an issue has been raised regarding the NBS for calcium, iron and zinc and a more targeted approach to improving these key nutrients may be more effective than implementation of further standards.

In recent years the NHS has moved towards a patient-centred approach, placing the emphasis on changing health -related behaviour and developing the communication skills of healthcare staff. Registered Dietitians (RDs) have an important role in supporting patients with health -related behaviour change and are required to communicate effectively with patients. The aim of this research, using a mixed methods approach, was to explore and develop the area of Communication Skills for Behaviour Change (CSBS) within one-to-one consultations between patients and RDs in the UK. A cross-sectional survey of British Dietetic Association (BDA) members was undertaken to ascertain their views on the use of CSBC in dietetics and preferred teaching methods at both pre- and post- registration level. A tool for the assessment of CSBC within dietetic patient consultations (DIET-COMMS) was developed and tested for its psychometric properties and utility in practice. Finally semi-structured interviews were undertaken with experienced RDs who had undertaken inter-rater reliability testing with DIET-COMMS to explore their views on best practice for CSBC in dietetics.

Malnutrition is a serious and common problem in older adults. This study aimed to determine and compare the nutritional status and factors affecting malnutrition in older adults in different care settings in the UK and Malaysia, in order to inform the development of setting and country-appropriate recommendations to reduce the prevalence and impact of malnutrition. An observational study was conducted in the UK and Malaysia involving 151 older adults aged 75 years and over in free-living, care home and hospital Data was collected using the Mini Nutritional Assessment (MNA), the Satisfaction with Food-related Life (SWFL) questionnaire, and 3-day 24hr recalls. Attitudes of 41 staff towards the nutritional care of older patients, the food access experience of 150 patients and a menu audit of 155 lunch time meals served, consumed and wasted were assessed in an additional study in hospital. Dietary data were analysed using Dietplan 6 and all data were analysed using SPSS (v16). Prevalence of malnutrition was higher among Malaysian older adults in all care settings, over their UK counterparts, while older patients in hospitals had the highest prevalence of malnutrition than other care settings in both countries. Although hospital food contained adequate levels of energy and protein, protein consumption was inadequate in the UK hospital setting, suggesting that it is the intake of hospitalised patients rather than the provision that is problematic. However energy consumption was inadequate in all care settings in both countries, suggesting that older adults are not eating enough to meet their estimated needs and the risk of malnutrition is widespread in older adults. This research has identified that the satisfaction with food-related life is the strongest unique indicator of malnutrition in this group and may present a simple early warning measure of malnutrition risk in older adults.

Beneficial health effects of anthocyanin-rich fruits and vegetables have been well documented. Subsequently extensive research on anthocyanins has been carried out to better understand the behaviour of anthocyanins. Bioavailability is one aspect which has been frequently investigated but the studies have not studied factors affecting anthocyanin bioavailability. Knowledge of the mechanism of anthocyanin absorption is also lacking. A bioavailability study was conducted with human volunteers whose urine was analysed following consumption of strawberry and red grape juice. Since anthocyanins are absorbed and present in biological fluids, their interactions with human serum albumin (HSA) were further examined. The study was then completed with an in-vitro test using Caco-2 cells to assess the uptake of anthocyanins by intestinal cells, and factors affecting uptake and the absorption mechanism through the apical cellular membrane.