ASU Electronic Theses and Dissertations
This collection includes most of the ASU Theses and Dissertations from 2011 to present. ASU Theses and Dissertations are available in downloadable PDF format; however, a small percentage of items are under embargo. Information about the dissertations/theses includes degree information, committee members, an abstract, supporting data or media.
In addition to the electronic theses found in the ASU Digital Repository, ASU Theses and Dissertations can be found in the ASU Library Catalog.
Dissertations and Theses granted by Arizona State University are archived and made available through a joint effort of the ASU Graduate College and the ASU Libraries. For more information or questions about this collection contact or visit the Digital Repository ETD Library Guide or contact the ASU Graduate College at gradformat@asu.edu.
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- Creators: Johnston, Carol
Description
Vitamin B12, found only in animal products, is a water-soluble vitamin important for DNA methylation, purine and pyrimidine synthesis, and the myelination of nerves. Symptoms of vitamin B12 deficiency include anemia, gait disturbances, altered vibration proprioception, impaired vision, psychosis, depression, dementia-like illness, and ultimately death. Because vegetarians and vegans consume fewer animal products in their diet than omnivores, they are inherently more at risk for developing these symptoms of vitamin B12 deficiency. Thus, the purpose of this study is to examine the correlation between nervous system markers (balance, dexterity, and vibration sensitivity) and markers of vitamin B12 nutriture (serum B12 and serum holo-transcobalamin II) in a cross-sectional study (n=38). In addition, the impact of daily oral vitamin B12 supplementation on these markers in an 8-week randomized controlled trial was also examined (n=18). The results of the cross-sectional study revealed a moderate correlation (R=-0.351, p=0.031) between serum B12 and left-hand functional dexterity. The results of the intervention study revealed no significant time*group interactions for markers of nervous system functions and biochemical values (after the removal of outliers). In addition, the time*group interaction appeared to be larger for those individuals with a baseline serum B12 of less than 303 pmol/L. These results suggest that vitamin B12 supplementation may have a more pronounced effect on those individuals who are in a state of vitamin B12 depletion (<303 pmol/L serum concentration). In addition, the results also suggest that 8 weeks of oral supplementation is not a long enough period to create significant clinical change, and it is likely that improvements in neurological measures would require long-term supplementation.
ContributorsArnold, Taylor (Author) / Johnston, Carol (Thesis advisor) / Whisner, Corrie (Committee member) / Ohri-Vachaspati, Punam (Committee member) / Lee, Chong (Committee member) / Aleck, Kyrieckos (Committee member) / Arizona State University (Publisher)
Created2016
Description
Vinegar is gaining popularity as a natural and proven treatment for common diseases and conditions ranging from high blood pressure to diabetes. While the evidence to support the benefits of vinegar is growing, few studies have considered possible negative consequences. One concern relates to the effect of vinegar on saliva pH and dental erosion. The aim of this study is to explore this relationship as well as unsubstantiated claims that vinegar, although acidic, has an alkalizing effect on the overall body, specifically looking at its effect on resting saliva pH. Healthy adults aged 18-45 were recruited for this trial. Twenty-two participants completed this eight-week, parallel-arm, randomized, double blinded study that looked at the effect that regular consumption of red wine vinegar (two tablespoons taken two times per day before a meal) had on resting salivary pH and dental erosion compared to a control (low dosage vinegar pill taken two times a day before a meal). Resting saliva pH was measured at home using the pH20H application and pH strips at week 0 and 8 of the trial. Erosion was noted using the Basic Erosive Wear Examination (BEWE) by a registered dental hygienist at week 1 and 8 of trial. Results indicate no mean difference in resting salivary pH in either treatment group after eight weeks (p value, 0.49). However, there was a statistical significant mean difference in dental erosion between the VIN and CON group (p value, 0.05). Statistical significance in dental erosion, typically a gradual process, in just eight weeks is a significant finding and warrants concern about long time use of vinegar and dental health. Further exploration into this relationship is needed.
ContributorsAnderson, Summer Lynn (Author) / Johnston, Carol (Thesis advisor) / Whisner, Corrie (Committee member) / Alexon, Christy (Committee member) / Arizona State University (Publisher)
Created2019
Description
Vitamin D deficiency has been previously associated with a higher Alzheimer’s disease (AD) risk, a condition marked by dependent living and severe cognitive impairment. AD is histologically defined by the presence of brain amyloid beta (Aβ) plaques and neurofibrillary tangles. Ways to enhance Aβ clearance have been examined in order to sustain cognition and delay AD onset. In vitro and in vivo studies suggest that vitamin D might enhance brain Aβ transportation to the periphery by up-regulating P-glycoprotein production. The purpose of this study was to examine the effect of vitamin D supplementation on plasma Aβ in an older population.
This study was a parallel-arm, double-blinded, randomized control trial. Participants consumed either a vitamin D supplement or placebo once a week for eight weeks (n=23). Only vitamin D insufficient (serum total 25-OH, D < 30 ng/mL) people were included in the study, and all participants were considered to be cognitively normal (MMSE scores > 27). Serum total 25-OH, D and plasma Aβ1-40 measurements were recorded before and after the eight-week trial. The plasma Aβ1-40 change was compared between the vitamin D group and control group.
The vitamin D group experienced a 45% greater change in plasma Aβ1-40 than the control group. The effect size was 0.228 when controlling for baseline plasma Aβ1-40 (p=0.045), 0.197 when controlling for baseline plasma Aβ1-40 and baseline physical activity (p=0.085), and 0.179 when controlling for baseline plasma Aβ1-40, baseline physical activity, and age (p=0.116). In conclusion, vitamin D supplementation might increase brain Aβ clearance in humans, but physical activity and age also appear to modulate Aβ metabolism.
This study was a parallel-arm, double-blinded, randomized control trial. Participants consumed either a vitamin D supplement or placebo once a week for eight weeks (n=23). Only vitamin D insufficient (serum total 25-OH, D < 30 ng/mL) people were included in the study, and all participants were considered to be cognitively normal (MMSE scores > 27). Serum total 25-OH, D and plasma Aβ1-40 measurements were recorded before and after the eight-week trial. The plasma Aβ1-40 change was compared between the vitamin D group and control group.
The vitamin D group experienced a 45% greater change in plasma Aβ1-40 than the control group. The effect size was 0.228 when controlling for baseline plasma Aβ1-40 (p=0.045), 0.197 when controlling for baseline plasma Aβ1-40 and baseline physical activity (p=0.085), and 0.179 when controlling for baseline plasma Aβ1-40, baseline physical activity, and age (p=0.116). In conclusion, vitamin D supplementation might increase brain Aβ clearance in humans, but physical activity and age also appear to modulate Aβ metabolism.
ContributorsMiller, Brendan Joseph (Author) / Johnston, Carol (Thesis advisor) / Whisner, Corrie (Committee member) / Tasevska, Natasha (Committee member) / Arizona State University (Publisher)
Created2015