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- Creators: Barrett, The Honors College
- Creators: Sweazea, Karen
- Status: Published
Description
ABSTRACT The hormone leptin is an important regulator of body weight and energy balance, while nitric oxide (NO) produced in the blood vessels is beneficial for preventing disease-induced impaired vasodilation and hypertension. Elevations in the free radical superoxide can result in impaired vasodilation through scavenging of NO. Omega 3 is a polyunsaturated fatty acid that is beneficial at reducing body weight and in lowering many cardiovascular risk factors like atherosclerosis. The present study was designed to examine the change in plasma concentrations of leptin, nitric oxide, and the antioxidant superoxide dismutase in addition to examining the association between leptin and NO in healthy normal weight adult female subjects before and following omega 3 intakes. Participants were randomly assigned to either a fish oil group (600 mg per day) or a control group (1000 mg of coconut oil per day) for 8 weeks. Results showed no significant difference in the percent change of leptin over the 8 week supplementation period for either group (15.3±31.9 for fish oil group, 7.83±27 for control group; p=0.763). The percent change in NO was similarly not significantly altered in either group (-1.97±22 decline in fish oil group, 11.8±53.9 in control group; p=0.960). Likewise, the percent change in superoxide dismutase for each group was not significant following 8 weeks of supplementation (fish oil group: 11.94±20.94; control group: 11.8±53.9; p=0.362). The Pearson correlation co-efficient comparing the percent change of both leptin and NO was r2= -0.251 demonstrating a mildly negative, albeit insignificant, relationship between these factors. Together, these findings suggest that daily supplementation with 600 mg omega 3 in healthy females is not beneficial for improving these cardiovascular risk markers. Future studies in this area should include male subjects as well as overweight subjects with larger doses of fish oil that are equivalent to three or more servings per week. The importance of gender cannot be underestimated since estrogen has protective effects in the vasculature of females that may have masked any further protective effects of the fish oil. In addition, overweight individuals are often leptin-resistant and develop impaired vasodilation resulting from superoxide-mediated scavenging of nitric oxide. Therefore, the reported antioxidant and weight loss properties of omega 3 supplementation may greatly benefit overweight individuals.
ContributorsAlanbagy, Samer (Author) / Sweazea, Karen (Thesis advisor) / Johnston, Carol (Committee member) / Shepard, Christina (Committee member) / Lespron, Christy (Committee member) / Arizona State University (Publisher)
Created2014
Description
For animals that experience annual cycles of gonad development, the seasonal timing (phenology) of gonad growth is a major adaptation to local environmental conditions. To optimally time seasonal gonad growth, animals use environmental cues that forecast future conditions. The availability of food is one such environmental cue. Although the importance of food availability has been appreciated for decades, the physiological mechanisms underlying the modulation of seasonal gonad growth by this environmental factor remain poorly understood.
Urbanization is characterized by profound environmental changes, and urban animals must adjust to an environment vastly different from that of their non-urban conspecifics. Evidence suggests that birds adjust to urban areas by advancing the timing of seasonal breeding and gonad development, compared to their non-urban conspecifics. A leading hypothesis to account for this phenomenon is that food availability is elevated in urban areas, which improves the energetic status of urban birds and enables them to initiate gonad development earlier than their non-urban conspecifics. However, this hypothesis remains largely untested.
My dissertation dovetailed comparative studies and experimental approaches conducted in field and captive settings to examine the physiological mechanisms by which food availability modulates gonad growth and to investigate whether elevated food availability in urban areas advances the phenology of gonad growth in urban birds. My captive study demonstrated that energetic status modulates reproductive hormone secretion, but not gonad growth. By contrast, free-ranging urban and non-urban birds did not differ in energetic status or plasma levels of reproductive hormones either in years in which urban birds had advanced phenology of gonad growth or in a year that had no habitat-related disparity in seasonal gonad growth. Therefore, my dissertation provides no support for the hypothesis that urban birds begin seasonal gonad growth because they are in better energetic status and increase the secretion of reproductive hormones earlier than non-urban birds. My studies do suggest, however, that the phenology of key food items and the endocrine responsiveness of the reproductive system may contribute to habitat-related disparities in the phenology of gonad growth.
Urbanization is characterized by profound environmental changes, and urban animals must adjust to an environment vastly different from that of their non-urban conspecifics. Evidence suggests that birds adjust to urban areas by advancing the timing of seasonal breeding and gonad development, compared to their non-urban conspecifics. A leading hypothesis to account for this phenomenon is that food availability is elevated in urban areas, which improves the energetic status of urban birds and enables them to initiate gonad development earlier than their non-urban conspecifics. However, this hypothesis remains largely untested.
My dissertation dovetailed comparative studies and experimental approaches conducted in field and captive settings to examine the physiological mechanisms by which food availability modulates gonad growth and to investigate whether elevated food availability in urban areas advances the phenology of gonad growth in urban birds. My captive study demonstrated that energetic status modulates reproductive hormone secretion, but not gonad growth. By contrast, free-ranging urban and non-urban birds did not differ in energetic status or plasma levels of reproductive hormones either in years in which urban birds had advanced phenology of gonad growth or in a year that had no habitat-related disparity in seasonal gonad growth. Therefore, my dissertation provides no support for the hypothesis that urban birds begin seasonal gonad growth because they are in better energetic status and increase the secretion of reproductive hormones earlier than non-urban birds. My studies do suggest, however, that the phenology of key food items and the endocrine responsiveness of the reproductive system may contribute to habitat-related disparities in the phenology of gonad growth.
ContributorsDavies, Scott (Author) / Deviche, Pierre (Thesis advisor) / Sweazea, Karen (Committee member) / McGraw, Kevin (Committee member) / Orchinik, Miles (Committee member) / Warren, Paige (Committee member) / Arizona State University (Publisher)
Created2014
Description
Reproduction is energetically costly and seasonal breeding has evolved to capitalize on predictable increases in food availability. The synchronization of breeding with periods of peak food availability is especially important for small birds, most of which do not store an extensive amount of energy. The annual change in photoperiod is the primary environmental cue regulating reproductive development, but must be integrated with supplementary cues relating to local energetic conditions. Photoperiodic regulation of the reproductive neuroendocrine system is well described in seasonally breeding birds, but the mechanisms that these animals use to integrate supplementary cues remain unclear. I hypothesized that (a) environmental cues that negatively affect energy balance inhibit reproductive development by acting at multiple levels along the reproductive endocrine axis including the hypothalamus (b) that the availability of metabolic fuels conveys alterations in energy balance to the reproductive system. I investigated these hypotheses in male house finches, Haemorhous mexicanus, caught in the wild and brought into captivity. I first experimentally reduced body condition through food restriction and found that gonadal development and function are inhibited and these changes are associated with changes in hypothalamic gonadotropin-releasing hormone (GnRH). I then investigated this neuroendocrine integration and found that finches maintain reproductive flexibility through modifying the release of accumulated GnRH stores in response to energetic conditions. Lastly, I investigated the role of metabolic fuels in coordinating reproductive responses under two different models of negative energy balance, decreased energy intake (food restriction) and increased energy expenditure (high temperatures). Exposure to high temperatures lowered body condition and reduced food intake. Reproductive development was inhibited under both energy challenges, and occurred with decreased gonadal gene expression of enzymes involved in steroid synthesis. Minor changes in fuel utilization occurred under food restriction but not high temperatures. My results support the hypothesis that negative energy balance inhibits reproductive development through multilevel effects on the hypothalamus and gonads. These studies are among the first to demonstrate a negative effect of high temperatures on reproductive development in a wild bird. Overall, the above findings provide important foundations for investigations into adaptive responses of breeding in energetically variable environments.
ContributorsValle, Shelley (Author) / Deviche, Pierre (Thesis advisor) / McGraw, Kevin (Committee member) / Orchinik, Miles (Committee member) / Propper, Catherine (Committee member) / Sweazea, Karen (Committee member) / Arizona State University (Publisher)
Created2018
Description
Dogs' health and wellbeing is of great importance to their owners. The most common nutritional problem for pet dogs is obesity, with 22-40% of pet dogs being classified as overweight or obese. With many adverse health effects associated with obesity, this is a major concern for owners and veterinarians. The degree to which dogs enjoy consuming certain foods can have substantial implications for their body weight, so it is important to understand which aspects of foods make them appealing to dogs. This study aimed to determine whether nutritional aspects of commercial dog foods predict dogs' preferences for those foods. It was found that consumption preference is positively correlated with protein content (p < .001), therefore implying that the protein content of commercial dry dog foods may predict dogs' consumption preferences. Consumption preferences were not predicted by other available measures of food content or caloric value. Dogs' preference for foods high in protein content may be due to the satiating effect of protein. Since foods high in protein both reduce the amount of energy consumed and are found to be palatable to dogs, high-protein dog foods may offer a way for dog food manufacturers, veterinarians, and pet owners to combat obesity in pet dogs.
ContributorsPrevost, Emily Danielle (Author) / Wynne, Clive (Thesis director) / Hall, Nathaniel (Committee member) / School of Life Sciences (Contributor) / Department of Psychology (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Brown adipose tissue (BAT) is thought to be important in combating obesity as it can expend energy in the form of heat, e.g. thermogenesis. The goal of this study was to study the effect of injected norepinephrine (NE) on the activation of BAT in rats that were fed a high fat diet (HFD). A dose of 0.25 mg/kg NE was used to elicit a temperature response that was measured using transponders inserted subcutaneously over the BAT and lower back and intraperitoneally to measure the core temperature. The results found that the thermic effect of the BAT increased after the transition from low fat diet to a high fat diet (LFD) yet, after prolonged exposure to the HFD, the effects resembled levels found with the LFD. This suggests that while a HFD may stimulate the effect of BAT, long term exposure may have adverse effects on BAT activity. This may be due to internal factors that will need to be examined further.
ContributorsSion, Paul William (Author) / Herman, Richard (Thesis director) / Borges, Chad (Committee member) / School of Molecular Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
Background: The prevalence of childhood obesity has disproportionately affected Latino youth and can be seen with an increase incidence of Type 2 Diabetes. This increase in obesity can be attributed to physical inactivity. Increases in social support and self-efficacy are independently related to increases in physical activity. A lifestyle intervention can lead to increases in social support, self-efficacy and physical activity. Objective/Hypothesis: The objective of this study was to determine whether a 12-week lifestyle intervention could increase social support, self-efficacy and physical activity in obese Latino adolescents that participated in the intervention. It was hypothesized that adolescents that participated in the intervention would increase self-efficacy, social support from family and friends, and physical activity compared to their control counterparts. Study Design/Participants: In a randomized control trial, there were 125 Latino (n= 60 experimental group; n= 65 control group; mean age = 15.17 +- 1.65 Males n = 60; n = 65 females) participants included in this study. Participants were also required to have a BMI percentile >= 95th percentile for age and gender or BMI >= 30 kg/m2. Methods: The intervention, which was developed using the Social Cognitive Theory had components focusing on social support and self-efficacy and also consisted of nutrition education classes and physical activity sessions for 12 weeks. The psychosocial constructs of self-efficacy and social support were measured using the Adolescent Self-Efficacy for Diet and Activity Behaviors and Adolescent Social Support for Diet and Exercise Survey, respectively. Physical activity was assessed by the 3-day Physical Activity Recall. Results: We found significant increases in social support in family (p = 0.042) and vigorous physical activity (p = 0.001). There was also a significant difference between control and treatment group for moderate to vigorous physical activity after the intervention (p = 0.027). There were no changes in social support from friends or self-efficacy. Conclusion: We concluded that a 12-week lifestyle intervention did lead to changes in social support and physical activity behaviors. These changes could have been influenced by the intervention as they were measured these constructs pre/post intervention.
ContributorsRahman, Hanna (Author) / Shaibi, Gabriel (Thesis director) / Hoffner, Kristin (Committee member) / School of Nutrition and Health Promotion (Contributor) / School of Social and Behavioral Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Epigenetic mechanisms such as DNA methylation have been found to affect metabolic processes, which leads to conditions like type 2 diabetes and obesity. The aim of this project was to validate differentially methylated cytosines (DMCs) identified in skeletal muscle from seven obese, non-diabetic women pre- and 3 months post- Roux-en-Y gastric bypass surgery. DNA samples extracted from skeletal muscle were sent to the Mayo Genotyping Core to undergo reduced representation bisulfite sequencing (RRBS). Differentially methylated cytosines at chr14.105353824 of the gene CEP170B, chr19.16437949 of the KLF2 gene, chr7.130126082 of MEST, and chr15.62457572 of C2CD4B were captured from the RRBS analysis using MethylSig. Bisulfite sequencing PCR (BSP) was performed on all DMCs listed above which resulted in no significant changes in methylation post-surgery. It was concluded that an alternate, more precise method should be used for validation of the RRBS, such as pyrosequencing.
ContributorsKelley, Conley Lane (Author) / Coletta, Dawn K. (Thesis director) / Roust, Lori R. (Committee member) / School of Human Evolution and Social Change (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Obesity has become a major area of research in many fields due to the increasing obesity rate not only in The United States, but also around the world. Research concerning obesity stigma has both physical and mental health implications. Weight bias and obesity stigma represent important research areas for health professionals as they confront these issues on a daily basis in interactions with their patients. To explore how gender, ethnicity, and a person's own BMI affect the stigma of certain weight related terms, a set of 264 participant's surveys on weight related situations on the campus of Arizona State University were analyzed. Using univariate analysis to determine frequency of words deemed most or least acceptable as well as independent t-test for gender and ANOVA for ethnicity and own BMI, we found that participant's view more clinical terms such as "unhealthy BMI" and "BMI" as acceptable words for use during a physician-patient interaction. Analysis across genders revealed the highest number of differences in terms, with females generally ranking terms across the board as less acceptable then men. Differences varied little between ethnicities; however, own BMI revealed more differences between terms; underweight participants did not rank any terms as positive. We analyzed average ATOP (Attitudes Toward Obese People) scores and found that there was no significant difference in average ATOP scores between gender and a participant's own BMI, but a statistical significance did exist between ethnic categories. This study showed that the term "obese/obesity", although normally considered to be a clinical term by many was not ranked as very positive across gender, ethnicity, or own BMI. Based on these findings, new material should be created to inform physicians on how to talk about weight related problems with certain populations of patients.
ContributorsBlasco, Drew Adair (Author) / Wutich, Amber (Thesis director) / Brewis Slade, Alexandra (Committee member) / Barrett, The Honors College (Contributor) / School of Politics and Global Studies (Contributor) / Department of Psychology (Contributor) / School of Human Evolution and Social Change (Contributor)
Created2014-12
Description
This creative project examines the effectiveness of several school based nutritional education and parent based programs along with multi-component interventions. Six published articles were reviewed and summarized to identify the most successful interventions to prevent childhood obesity. In addition to these studies other resources were examined to understand the developmental levels of school-aged and adolescent students. As part of this project a narrated power point covering the key aspects of the nutritional needs of the school-aged child was developed. This power point will be utilized by future nursing students whom are working with parents in the schools or in the community on nutrition strategies. The power point will provide a context for individual or group discussions with parents to offer helpful ideas on how to work effectively with their children. The topic of nutrition and obesity in school-aged children is a current topic in health care especially in environments where nutritional resources are limited. The overall outcome of this project will be to assist in decreasing the incidence of overweight and obese youth and the prevention of the development of premature chronic diseases especially in early adolescence and young adulthood.
ContributorsLopez, Leticia Marie (Author) / Hosley, Brenda (Thesis director) / Speer, Therese (Committee member) / Storto, Pamela (Committee member) / Barrett, The Honors College (Contributor) / Arizona State University. College of Nursing & Healthcare Innovation (Contributor)
Created2014-12
Description
This project explores a variety of ways of framing the problem of obesity, beginning with a multidisciplinary assessment of genetic, environmental, cultural, nutritional, and socioeconomic factors involved in the structure and the consequences of each frame. How obesity is framed as a problem has a profound impact on the kinds of solutions that may be deemed scientifically appropriate. But frames are not entirely evidence-based, inasmuch as political and moral values infuse debates about the nature of obesity. Drawing on interdisciplinary resources from bioethics and the philosophy of science, I strive to offer strategic insight in to how to navigate the complexity of these issues.
ContributorsYanamandra, Meghana (Author) / Robert, Jason (Thesis director) / Wharton, Christopher (Committee member) / Drago, Mary (Committee member) / Barrett, The Honors College (Contributor) / School of Sustainability (Contributor) / School of Life Sciences (Contributor) / School of Human Evolution and Social Change (Contributor)
Created2014-05