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Thesis (Ph. D)--UCLA, 2007. / Vita. Includes bibliographical references.

Made available in DSpace on 2014-06-11T19:35:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-10-27Bitstream added on 2014-06-13T20:07:19Z : No. of bitstreams: 1 cardone_ib_dr_rcla.pdf: 865526 bytes, checksum: cfb758eeff51189ee9007d1f02cd68c0 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / O alto curso do rio Corumbataí (SP) possui grande diversidade de loricariídeos do gênero Hypostomus (Ostariophysi, Loricariidae), conhecidos popularmente por cascudos. As espécies coletadas neste trecho do rio foram: Hypostomus strigaticeps, H. albopunctatus, H. ancistroides, H. regani, Hypostomus sp. C e Hypostomus sp. B. Foi constatada a grande dominância de H. strigaticeps. Há homogeneidade na dieta quanto ao consumo e importância de sedimento grosso, sedimento fino, hifas de fungo, Tecamoeba e diatomáceas, como resultado daquilo que as espécies encontram no ambiente e consomem ao raspar o substrato. Diferentemente das demais, observou-se a preferência de H. albopunctatus por material vegetal. O Coeficiente de Sobreposição Alimentar de Morisita-Horn, indicou alta sobreposição alimentar entre todas as espécies em todas as estações do ano, embora H. albopunctatus tenha apresentado menor similaridade trófica. As espécies foram agrupadas de acordo com as semelhanças de suas características morfológicas relacionadas à dieta utilizando-se Distância Euclidiana. As matrizes de similaridade trófica e morfológica foram testadas pelo teste de Mantel e constatada correlação entre elas. As características da morfologia trófica das espécies relacionam-se ao ambiente bentônico do rio e a dieta iliófaga-detritívora das espécies. A ingestão de material vegetal na dieta de H. albopunctatus tem relação com seu intestino proporcionalmente menos longo se comparado aos das demais espécies mais iliófagas e menos herbívoras. A similaridade na dieta pode explicar a supremacia em biomassa de H. strigaticeps. É possível que a maior segregação ecológica seja relacionada aos micro-habitats utilizados pelas espécies. As discretas diferenças na dieta das espécies estudadas neste trabalho podem sugerir locais diferentes para forrageamento. / The Corumbataí River (SP) possess great diversity of Hypostomus (Ostariophysi, Loricariidae), commonly known as armored catfishes. The species collected in the Corumbataí River uplands were Hypostomus albopunctatus, H. ancistroides, H. strigaticeps, H. regain, Hypostomus sp. C and Hypostomus sp. B. It was also noticed a great dominance of H. strigaticeps. There is a homogeneity of the fish diet, when consisting of small and great sediment particles, fungi hifas, Tecamoeba and diatoms, as a result of the most common material the species find in the environment and consume by grasping the substratum. A preference of H. albopunctatus for vegetal debris was also observed. The Feeding Superposition Coefficient of Morisita-Horn showed a high overlap of the food consumed by all the species at all the year seasons. Besides this overlap, H. albopunctatus presented the lowest index of trophic similarity. Species were grouped according to their morphologic similarity, using the Euclidian Distance. The trophic and morphologic similarity matrices were tested using the Mantel test which showed a correlation among them. The morphologic characters of the species are related to the benthic environment in the river and to the iliophagic-detritivorous diet the species present. The distinct ingestion of vegetal debris observed for H. albopunctatus may be related to its comparatively shorter intestine when compared to all other species, more iliophagics and less herbivorous. The diet similarity may be a fact to explain the biomass supremacy of one of them, which is H, strigaticeps. Though not observed in this study, a spacial segregation may happen, the species using distinct micro-habitats. The discrete distinctions of food components found in the distinct fish guts may indicate distinct places explored by them.

El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / Studies assessing the association between vegetarianism and mental health have found divergent results. Evidence from adolescents in developing countries is scarce. To evaluate the association between a vegetarian diet and emotional symptoms in 15-year-old adolescents from Ethiopia, India, Peru and Vietnam. A cross-sectional, secondary analysis of the Young Lives cohort study was used. The exposure variable was the self-report of being a vegetarian (yes or no). The outcome was the level of emotional symptoms, numerically evaluated using the score obtained in the subscale "Emotional Symptoms" of the Strengths and Difficulties Questionnaire (SDQ). We calculated crude and adjusted coefficients (β) with 95% confidence intervals (95% CIs), using generalized linear models of the Gaussian family, considering each sentinel site as a cluster. The analysis was stratified by country. Additionally, we made a global analysis including the four countries. A total of 3484 adolescents were analyzed. The overall prevalence of vegetarianism was 4.4%, but it varied between countries (from 0.4% in Vietnam to 11.5% in India). The average emotional symptoms score was 3.5 [standard deviation (SD) 2.3] points. The scores were not statistically different between vegetarians and non-vegetarians (p > 0.05). In the adjusted analysis, in Vietnam, vegetarians had lower emotional symptoms scores on average than non-vegetarians [β: -1.79; 95% CI: -3.05 to -0.55]. No differences were found neither in the other countries nor in the overall sample. There was no association between a vegetarian diet and emotional symptoms in the analyzed adolescents of four developing countries. / Revisión por pares

The recently accepted phenomenon of adult neurogenesis is important for basic biological research and, potentially, can have major implications for the treatment of age-related cognitive decline and disease. Investigation into the mechanisms of adult neurogenesis and its ability to replenish brain circuits with new functional neurons requires whole animal models.  Zebrafish, a diurnal vertebrate, has robust cell proliferation in several neurogenic niches, including the cerebellum and dorsal telencephalon, the latter bearing homology to mammalian hippocampus. Because zebrafish demonstrate rapid regeneration in all tissues, including successful repair following brain traumas, they are promising as a model for designing therapies for human brain traumas or stroke. Their long lifespan and gradual aging also makes them an interesting model for the role of neurogenesis in counteracting human neurodegenerative disorders of aging. In different models, it has been found that cell proliferation in adult brain can be significantly affected by behavioral and environmental factors. Among those is nutrition, impacting adult neurogenesis through the amount of caloric intake, meal frequency, and meal content. The study presented here addressed the effects of nutritional factors on adult neurogenesis in a zebrafish model of premature aging due to excessive caloric food intake since early development. Fish were exposed to fasting, different diets and feeding schedules, with the rate of cell proliferation documented in two largest neurogenic niches of the zebrafish brain, the cerebellum and dorsal telencephalon. Here we show that, under normal conditions, fish with premature aging demonstrate dramatic decline in adult neurogenesis in both niches, when compared to age-matched control. The present findings establish an effect of nutrition on neurogenesis in the cerebellum and dorsal telencephalon of adult zebrafish. Zebrafish maintained on HFD, subjected to fasting, or fed only in the evenings showed significant changes in neurogenesis in two distinct neurogenic niches from that of control fish. Remarkably, the two brain regions under investigation displayed partially different responses to nutrition related factors. This was reflected in the cerebellar niche in which neurogenesis was significantly increased by 24h fast/24h refeed, high fat diet, and evening feeding conditions.  Neurogenesis of the cerebellum was significantly decreased in 24h fast, 42h fast/refeed conditions.  In the dorsal telencephalon, neurogenesis was significantly amplified by high protein, and similar to the cerebellum, high fat diet and evening feeding conditions.  In contrast, neurogenesis of the dorsal telencephalon was significantly attenuated only in the 72h fasting condition. This study provides evidence that nutrition plays important role in the modulation of adult neurogenesis in zebrafish, and presence of niche-specific responses to nutritional factors. This further suggests that zebrafish can serve as a model for studying the effects of specific diets, metabolic factors and drugs that affect metabolism in search for prophylactic and therapeutic measures for age-related cognitive decline or neurodegenerative disorders.

Alzheimer’s Disease (AD) is the most common neurodegenerative brain disease worldwide. It primarily affects older adults and is characteristically marked by memory loss correlated with loss of functional brain tissue. As the human lifespan increases and without effective treatment, the number of people at-risk for AD will rise dramatically in the near future. Identifiable genotypic risk factors or causes are only present in a small number of AD patients, and thus environmental factors potentially exacerbating the disease should be examined. Here I reviewed the results of clinical trials examining the role of nutritional components in AD with the following conclusions. First, there are still not enough trials on nutrients affecting onset and progression of AD. Reasons include ethical difficulties of randomized studies controlling for nutrients that are important for overall human health. Thus, conclusions about cognitive benefits of such nutrients remain unknown. Second, the dosages, treatment lengths, and disease time points investigated are varied between studies, with varying results as well. However, studies that examined the role of dietary intervention in early-stage patients report more significant benefits. Third, the interaction of multiple facets of nutrition and general lifestyle factors may act in synergy to affect disease onset and progression. Finally, and perhaps most importantly, this review reiterates that neuronal loss, i.e. advanced AD, currently cannot be cured. Instead, the prevention and slow-down of the disease should be approached from as many angles as possible, including nutrition, exercise and social activities, as these factors influence human life every day over many years, affecting the health of the entire body, including the brain.

Interest in the ketogenic diet and its potential to treat obesity and type 2 diabetes has been steadily growing in recent years. With a very limited amount of calories coming from carbohydrates (typically < 50 gm/day), and the majority of calories coming from fat, this diet leads to a states of physiological ketosis, in which ketone bodies replace glucose as the primary source of energy. Early clinical trials found this to lead to a spontaneous reduction in calories consumed, and it has been suggested that a state of ketosis has appetite suppressing properties. There are a few studies evaluating self-reported decrease in hunger while consuming a ketogenic diet, as well as the changes in hormone levels associated with appetite, but this evidence is limited. The primary determinant of weight change is the difference between calories consumed and calories burned, however there is some suggestion that the macronutrient composition of the ketogenic diet may have a specific metabolic advantage for weight loss separate from the total number of calories in deficit. Multiple diet comparison studies have found the ketogenic diet to be effective for weight loss in the short term, particularly when compared to low fat diets. It is questionable whether the ketogenic diet is sustainable in the long term, particularly without frequent nutritional counseling and monitoring. Still, there is preliminary evidence that the ketogenic diet can lead not only to a large amount of weight loss, but may also be effective in treating and reversing type 2 diabetes. Clinical trials have shown decreases in HbA1c, fasting glucose, and reduction of antiglycemic medication requirements, though it is unclear if these effects are primarily due to weight loss itself, or the specific composition of the ketogenic diet. These benefits need to be weighed against the risks, and a common criticism is its high fat content which can adversely affect serum lipid levels and thus risk of cardiovascular disease. Consuming a ketogenic diet with a high intake of saturated fat has been found to increase LDL cholesterol, however this effect can be mitigated by favoring polyunsaturated or monounsaturated fats instead. While the above findings provide a preliminary understanding of the effects of the ketogenic diet, more research is needed to further elucidate the effectiveness and safety of the diet for treating obesity and type 2 diabetes.

Two clinical trials investigating the effect of modulating two dietary components, tea containing polyphenols and vitamin D aimed at improving non-haem iron absorption and iron status recovery, were carried out in a cohort of healthy and iron deficient UK women, respectively. Tea has been shown to be a potent inhibitor of non-haem iron absorption but it remains unclear whether the timing of tea consumption relative to a meal influences iron bioavailability, with limited published evidence, especially in human trials. The aim of the first study was to investigate the effect of tea consumption on non-haem iron absorption and to assess the effect of time interval of tea consumption on non-haem iron absorption relative to an iron-containing meal, in a cohort of healthy female participants using a stable iron isotope (57Fe).

Background: Celiac Disease (CD) is a chronic, autoimmune disease that prevents individuals from being able to process gluten. When individuals ingest gluten, their digestive system becomes severely damaged, leading to many adverse, health effects. It is, therefore, significantly crucial that individuals with CD adhere to a Gluten-Free diet (GFD). However, the adherence rate is well below optimal in the adult, CD population. Hence, it is crucial to identify and understand the factors that impact their ability to maintain a GFD. Objective: To develop a systematic review that critically appraises and synthesizes evidence on the facilitators and barriers that affect adherence to GFD among the adult population with CD. Data Sources: Ovid Medline, CINAHL, PsychInfo, and Embase were included, using a combination of keywords to retrieve relevant articles. The Inclusion Criteria consisted of empirical studies that focus on Adults with CD. Only English studies were considered. A coding scheme was developed to retrieve uniform information from each of the included studies, including: study design, population characteristics, facilitators and barriers presented, limitations, and a summary of each study. Results: Facilitators and Barriers were organized based on a Social ecological model, derived from the bioecological theory of development, which emphasizes that individuals make choices in their lives based on the impact of various ecological levels that exist. The ecological levels include: System, Community, Organizational, Interpersonal, and Individual. The studies included in this systematic review reported many facilitators and barriers that exist at the different ecological levels, which significantly affect adherence to GFD. Based on the frequency of articles that reported each facilitator and each of the studies’ level of evidence, the most significant facilitators were: increased patient education; celiac association membership; financial compensation/food subsidies; and increased intention/self-regulatory efficacy. When taking into consideration the frequency of articles that reported each barrier along with each of the studies’ level of evidence, the most significant barriers were: restaurant dining/supermarket shopping; poor patient education from practitioner; specific cultural factors; and low intention/motivation to adhere to a GFD. Although other factors have been reported, there was limited evidence to support them due to weak study designs, limited samples, and inconsistencies found across the different studies. It is important to understand that there are many additional facilitators and barriers retrieved in the systematic review that do not have as much evidence to support them. These are discussed in the thesis. Conclusion: Introducing policy changes at a health systems level will have the most influential impact on all the ecological layers in an individual’s life. Based on the magnitude of the results and the level of evidence of each of the studies, improvements to physician-patient communication, patient education interventions, and food subsidies, will create the most significant opportunity to positively impact the remaining ecological levels in one’s life, with the ultimate goal of improving adherence rates to a GFD among adults with CD in Canada. Registration: Prospero registration ID number is CRD42018091854.

Ballet dancing is a rigorous activity, the requisite skill acquisition for which begins at an early age. For girls, the activity requires a clearly defined body shape and composition, the attainment of which may result in low body weight and BNH, the development of eating disorders, menstrual dysfunction, and poor nutrient intake. The combination of the high levels of exercise for both sexes and the sylph-like figure required by females may have an effect upon growth and development, injury and repair, and long-term health. No evidence could be found in the literature of investigations on retired ballet dancers and the potential effects of their career upon their long-term health. Therefore, a retrospective study was carried out on sixty-three male and female dancers by means of a 'health' questionnaire. Although the results from the retrospective study showed that no serious health effects had occurred in the sample investigated, there was nevertheless a high incidence of injury amongst both sexes. During their career, the retired females were found to have had: low body weights, with many of them having been on slimming diets; a lack of knowledge concerning food and fluid intake; and poor menstrual status, including delays in menarche. It was concluded that many of the injuries sustained by the males could be attributed to their role of partnering and therefore constantly physically supporting and lifting the female dancers. No definitive work could be found on nutrient intakes of ballet dancers and no prospective studies appeared to have been carried out on the overall injury status of currently active female ballet dancers. None of the studies had concurrently assessed nutrient intake and injury status and factors which may affect this, as well as assessing their general wellbeing. Thus, thirty-eight pre-professional female ballet dancers were recruited to the prospective study. All types of injury from minor to major were recorded over a period of ten weeks, concurrent with life events and menstrual patterns. During this period, nutrient intake was also estimated over seven consecutive days using the weighed inventory method. The dancers completed a general background questionnaire; EAT-26 and BIT'E - two screening questionnaires clinically used to assess for the symptoms of anorexia and bulimia nervosa; and, a nutritional quiz compiled by the author and largely based on what the students had been taught. The dancers had significantly lower dietary intakes of energy, carbohydrate, fat, iron, and NSP than their relative DRV's. Low intakes of energy and particularly carbohydrate could reduce muscle glycogen concentrations, and thus promote fatigue. The dancers had busy schedulesw hich restrictedt heir ability to eat well and the majority of them had poor nutritional knowledge. The injury rates of the majority of the dancers were found to be high and a statistically significant correlation was found between these injury rates and fatigue. These findings suggest that the dancers needed to receive a more fruitful method of nutrition education and have less hectic schedules, a combination of which could well result in the dancers having greater opportunity to eat well and rest sufficiently to reduce their overall levels of fatigue, enhance their overall feeling of wellbeing, and thus, possibly, reduce the risk of injury.