With the rise in obesity, there has been an increased interest in foods which may beneficially affect appetite. Resistant starch (RS) and whole grains (of which RS is a main dietary fibre component) have been proposed to affect satiety and therefore may be beneficial in weight management. There is little direct evidence confirming this in humans. Whilst animal data suggest a positive effect of RS on appetite, the few existing human intervention studies provide inconsistent findings. For whole grains the majority of evidence is from epidemiological work as opposed to intervention studies. Therefore a series of studies was conducted to investigate effects of RS and whole grains on appetite and food intake. Two studies were conducted using RS. The first investigated the acute (24 hours) effects of 48 g RS in healthy adult males compared with an energy and available carbohydrate matched placebo. Following RS there was a significantly lower energy intake compared with placebo. There was also a significantly lower postprandial insulin response with RS, possibly explained by increased hepatic insulin clearance determined by a higher C-peptide to insulin ratio. In the second study 40 g RS consumed daily for 4 weeks was compared with the placebo, in overweight and obese participants. Effects on food intake were assessed and a frequently sampled intravenous glucose tolerance test (FSIVGTT) was conducted. This study found no effect on either appetite or energy intake, but did find significantly higher glucose, insulin and C-peptide concentrations, measured during the FSIVGTT, with the RS compared with the placebo, possibly explained by an improved first-phase insulin response. This finding did not translate into differences in parameters obtained from modelling the FSIVGTT data, but this and the lack of appetite and food intake differences could be explained by the small participant numbers. Two intervention studies were conducted with whole grains incorporated into bread rolls. The first, a crossover study, involved 3 weeks' daily consumption of 48 g milled whole grain or control, in young healthy adults. Whilst no significant difference was found between interventions in energy intake or subjective appetite ratings, a significantly lower systolic blood pressure was observed with the milled whole grains. The second was an 8 week parallel study (48 g intact or 48 g milled whole grains or control) in overweight and obese adults. No significant difference was found between groups on energy intake, subjective appetite ratings, cholesterol or postprandial metabolite concentrations. RS appears to be a possible satiating ingredient when consumed acutely and, whilst this was not confirmed in our chronic study, effects may have been masked by small participant numbers. A novel finding from our RS studies was an effect on the insulin response. These studies suggest that RS could have a beneficial role in weight management and favourable metabolic effects. Our whole grain interventions appear not to agree with epidemiological work that suggests a beneficial role on appetite, but there maybe effects on blood pressure regulation. In all instances further investigations are required in other population groups, with more participants and for longer time periods.

Epidemiological studies have shown that a diet high in fruit and vegetables has an inverse association with the occurrence of various degenerative diseases such as cancer, cardiovascular disease, neuro-degenerative disease and diabetes. Clinical and animal studies using fruit and vegetable extracts have shown that polyphenols abundant in plants may account for the beneficial effect of diets high in fruit and vegetables. Following these findings, laboratories worldwide are investigating the mechanisms underlying the health effects exerted by polyphenols. Although many studies have investigated the effect of various polyphenols on cancer cells, such as inhibition of cell growth, induction of apoptosis, tumorigenesis, few studies have been carried out to examine their effect on normal cells and whether they could prevent the initiation of cancer. DNA damage, one of the early steps in the tumorigenic process, may be caused by toxicants and oxidative stress either from the environment or from endogenous sources. Therefore, to prevent such damage, multiple mechanisms are deployed by cells to combat the toxic insult and reduce oxidative stress. The CNC-bZIP transcription factor, Nrf2, is known to regulate the expression of many of the genes involved in these processes. Under homeostatic conditions, the Nrf2 protein is targeted by its inhibitor Keap1 for ubiquitination in the cytosol. Upon redox stress, induced by low molecular weight electrophiles, Nrf2 can evade ubiquitination and translocate into the nucleus, where it heterodimerizes with members of the small Maf family of transcription factors and bind to the antioxidant response element (ARE) in the promoter region of many cellular defence genes, leading to the up-regulation of their transcription. In our study, we examined whether polyphenols could affect the Nrf2-ARE signalling pathway. Preliminary screening was first carried out using AREc32 cells to find flavonoids which have ARE-inducing ability. Flavonoids, which are present in relatively high concentration in fruits and vegetables and consumed most commonly, were chosen for screening. Quercetin and kaempferol showed the highest ARE-inducing ability and these two compounds were subsequently were used to examine their effect on Nrf2 and its target gene Nqo1 in rat liver RL-34 and mouse embryonic fibroblast MEF cells. By Nqo1 enzyme activity assay, Western blotting, and Taqman experiments, our study showed that these two flavonoids increased the enzyme activity, protein expression and mRNA level of Nqo1. By using Nrf2+/+ and Nrf2-/- MEFs, we found that such increases are Nrf2-dependent. The effect of quercetin and kaempferol on Nrf2 was therefore examined. Nrf2 protein, but not mRNA, was found to be elevated by quercetin and kaempferol. By cycloheximide-chase experiment, quercetin and kaempferol were shown to stabilize the Nrf2 protein by decreasing its turnover time. Furthermore, results from cellular fractionation and immunocytochemistry experiments showed that Nrf2 predominantly resides in nucleus under both normal and stressed conditions; the two flavonoids increased the accumulation of Nrf2 in both cytosol and nucleus, although the increase of Nrf2 protein in the nucleus was more pronounced. In addition, it was found that the flavonoids inhibited the ubiquitination of Nrf2. To address how the flavonoids inhibit the ubiquitination, we carried out mutagenesis experiments with quercetin and found Cys151 in Keap1 is required for stabilization of Nrf2, which indicates that quercetin may act as an electrophile and modify the Cys151 in Keap1, ultimately leading to the disruption of the association between Keap1 and Nrf2. The involvement of ARE in the regulation of Nqo1 by quercetin and kaempferol were examined by mutagenesis experiments, the results of which showed that the ARE was involved in both the basal expression of Nqo1 and its induction by quercetin and kaempferol. Besides the ARE, the promoter region of Nqo1 contains a xenobiotic responsive element (XRE) which can mediate gene regulation by AhR. With the evidence from previous research showing that Nqo1 can be up-regulated by the AhR agonist TCDD, we examined the involvement of XRE in the induction of Nqo1 by the flavonoids in mutagenesis experiments. The absence of XRE only affected the basal level but not the inducible level of Nqo1. However, by immunocytochemistry experiments, we showed that quercetin and kaempferol can act as AhR agonists. This was confirmed by Taqman experiments showing these two flavonoids can increase the mRNA level of Cyp1a1. Lastly, the effect of quercetin and kaempferol in vivo was also examined in animals by using C57BL/6 male mice. Only quercetin showed up-regulation of Cyp1a1 mRNA in the small intestine. An effect on Nqo1 and Nrf2 by the flavonoids observed in cells was not seen in the tissues. Taken together, the data presented in this thesis shows that the flavonols quercetin and kaempferol up-regulate the Nrf2-ARE signalling pathway by stabilizing the CNC-bZIP protein; such up-regulation also leads to the trans-activation of Nqo1. In addition, the two flavonoids are AhR agonists and increase the mRNA level of Cyp1a1 which is also observed in the mouse small intestine. Such increase of Cyp1a1 may indicate their implication in the prevention of gastrointestinal cancer

Recent research has shown that ideas about the past are central to the way people think about current food and construct alternatives. Yet there has been a lack of detailed attention paid to these uses of the past, often dismissed as nostalgic and inaccurate. This thesis examines the uses of ‘heritage’ as a very particular means of engagement with the past and takes as its subject the increasingly high profile idea of ‘heritage’ vegetables. One problem facing consumers and scholars alike hoping to understand the phenomenon and its effects is that heritage discourse is being used in very different and apparently contradictory ways by a wide range of interest groups. In order to understand the ways these different social actors use heritage to negotiate a place for themselves relative to both the heritage at stake and other groups, this study analysed a corpus of around 500 heritage vegetable texts. The thesis argues that the discourse is driven by a central narrative of loss, ongoing risk and guardianship, which serves to add value to materials, by producing them as heritage. It goes on to identify a series of patterned variations in the way social actors construct heritage value, variations afforded by the mutable materiality of vegetables, seeds and plants. While some groups emphasise the practice of heritage production and consumption or the sensory experience to be enjoyed through it, other groups deploy strategies to make the heritage more materially unambiguous. The thesis then moves on to examine the importance of the concept of guardianship, and its use as a mechanism for the staking of claims to manage and thereby control heritage resources. It demonstrates that there is a distinction to be drawn between those narratives which emphasise practice, and those which emphasise material heritage ‘treasure’. The former work to construct an accessible and participatory ‘networked’ concept of guardianship. The latter reinforce the role of professional heritage experts, and the storage of heritage in secure, closed collections. The thesis makes a contribution at the intersection of food and heritage studies, at a time when heritage is being used in more and more contexts relating to consumption and lifestyle. It suggests ways in which differences in the construction of heritage value have great implications for who is empowered to access the heritage thus created, and opens the way to further research into the ways heritage is being used in healthy eating, environmentalist and urban regeneration contexts.

The aim of this study was to identify dietary patterns during pregnancy and lactation of Saudi Arabian mothers, together with infant feeding practices and identify the beliefs and other factors which lie behind these patterns. The implications for the nutritional health of mother and baby were also explored. Data was collected in three separate studies: 1. An investigation of antenatal records of 92 mothers who had given birth to normal weight babies compared with records of 46 mothers who had given birth to babies weighing less than 2.500 kg. 2. Survey of dietary patterns and beliefs of 227 women attending the first antenatal appointment, recruited in Shaban (80), Shawal (76) and Ramadan (71). 3. A follow-up study of 51 mother-baby pairs to investigate dietary patterns, infant-feeding practices and anthropometric measurements at 1, 3, 6 and 9 months postpartum. Results indicate the influence of cultural beliefs on maternal diet during pregnancy, puerperium and lactation, including some influence of hot/cold food classification. The period of Ramadan not only profoundly affected maternal eating habits in pregnancy, but was also associated with low birth weight when it fell in the second trimester of pregnancy. Based on 24-hour recall data, the diets of most mothers in pregnancy and lactation failed to meet international recommendations. Some breast feeding of infants was almost universal and prolonged by western standards, but the decline during the study period indicated that the majority would not comply with the Quranic injunction to breast feed for 2 years. Anthropometric data of infants indicated the presence of stunting/wasting in a small number of infants.

Background: Current models of appetite control embody the view that tonic and episodic inhibitory signals modulate a constant and recurring drive to eat, but the source of this excitatory drive has been poorly defined. A motivational drive arising from energy needs would appear logical, but the influence of energy expenditure on energy intake remains unclear. Furthermore, while changes in eating behaviour and body composition following acute and chronic exercise are highly variable, a greater understanding of the compensatory mechanisms that mediate this heterogeneity is needed. Methods: A multi-level experimental platform was used in which body composition, metabolism and eating behaviour were measured concurrently in overweight and obese individuals in response to either an acute bout of aerobic exercise, or 12 weeks of supervised aerobic exercise training. This approach allowed for the disclosure of any interdependent relationships between physiological and behavioural components of energy balance. Results: The key findings of this thesis are novel and demonstrated that: • Fat-free mass is a physiological source of hunger that drives day-to-day food intake at a level proportional to basal energy requirements. This homeostatic signal of energy demand was apparent under sedentary conditions, and during exercise-induced weight loss. In contrast, fat mass did not appear to exert a major influence on hunger or food intake under sedentary conditions. • Following 12 weeks of aerobic exercise, marked individual variability existed in exercise-induced weight loss. • While there was no mean change in food intake following 12 weeks of aerobic exercise, fasting hunger increased significantly following the exercise intervention. However, this increase in orexigenic drive was off-set by a parallel increase in meal-related satiety. • Some individuals experienced a greater than expected decline in resting metabolic rate following the 12 week exercise intervention (that could not be explained by changes in body composition). Importantly, these individuals also demonstrated a concomitant increase in food intake following the intervention. • Leptin was found to play a key role in co-ordinating the physiological and behavioural responses to exercise-induced weight loss, with a decline in fasting leptin (independent of fat mass) associated with a greater than expected decline in resting metabolic rate, a smaller increase in resting fat oxidation, an increase in daily hunger, and an increased liking for high fat foods following the 12 week exercise intervention. Conclusions: An important role for fat-free mass in the control of appetite was identified. Furthermore, the impact of exercise on appetite control and body weight regulation was found to be mediated through a cluster of inter-related physiological and behavioural pathways, with leptin potentially acting to co-ordinate these adaptive responses.

What people eat influences their susceptibility to disease, yet many consumers within the Western World are consuming inappropriate diets. One approach to facilitating the consumption of a healthy diet has been the development of so-called "Functional Foods" (foods that provide a health benefit beyond the traditional nutrients they contain). The ultimate aim of the thesis was to model current psychological predictors of intention to consume functional foods. A mixed method approach was utilised. Qualitative (one-to-one interviews) and quantitative (questionnaire) exploratory studies were used to inform a larger qualitative study (focus groups). Emergent key information was then used to inform a large-scale questionnaire and structural equation modelling was used to identify the predictors of intention. The interview study highlighted the important issues surrounding functional foods. The small questionnaire determined the further research on a) conditions important to consumers and b) conditions that varied along a perceived genetic scale (Alzheimer's disease, Cardio Vascular Disease and Stress). The focus groups highlighted four design rules for the successful development of functional food ('inversion', `subterfuge', `inclusiveness' and `authenticity') and three key segments of the population ('pro-science', `conditionalists', and `negatives'). The final study modelled the three health conditions (Alzheimer's disease, Cardio Vascular Disease and Stress) and three preventative health behaviours (eating functional food, a healthy diet or doing more exercise). Multi-dimensional Health Locus of Control and perceived hazard characteristics were modelled as predictors of risk perception. The main predictors of risk perception differed significantly by health condition. Intentions for the three preventative health behaviours were modelled using a Theory of Planned Behaviour framework. Good predictive utility was demonstrated, which was further improved by expansion of the model. Output from the research could be used to inform both psychological theory and the design of future communication initiatives. Findings are discussed with respect to practical and methodological implications and directions for future research.

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