Theses and Dissertations
This collection includes both ASU Theses and Dissertations, submitted by graduate students, and the Barrett, Honors College theses submitted by undergraduate students.
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- All Subjects: Type 2 Diabetes
- Creators: Johnston, Carol
Description
Curcumin is an active ingredient of Curcuma longa (Turmeric) and is studied extensively for its antioxidant, anti-inflammatory, anti-bacterial, anti-viral, and anti-cancer properties. The purpose of this study was to examine the effects of turmeric on blood glucose and plasma insulin levels. The study utilized a placebo-controlled, randomized cross-over design with participants serving as their own control. Eight glucose tolerant healthy participants completed the full study. Three-weeks washout period was kept in between six-weeks. Prior to the test meal day, participants were asked to eat a bagel with their evening dinner. During the day of the test meal, participants reported to the test site in a rested and fasted state. Participants completed mashed potato meal tests with 500 mg of turmeric powder or placebo mixed in water, followed by 3 weeks of 500 mg turmeric or placebo supplement ingestion at home. During this visit blood glucose finger picks were obtained at fasting, 30, 60, 90, and 120 min post-meal. Blood plasma insulin at fasting and at 30 min after the test meal were also obtained. During week 4, participants reported to the test site in a rested and fasted state where fasting blood glucose finger pricks and blood plasma insulin were measured. During week 5 to 7, participants were given a washout time-period. During week 8, entire process from week 1 to 4 was repeated by interchanging the groups. Compared to placebo, reduction in postprandial blood glucose and insulin response were non-significant after ingestion of turmeric powder. Taking turmeric for 3 weeks had no change in blood glucose and insulin levels. However, taking turmeric powder supplements for 3 weeks, showed a 4.4% reduction in blood glucose. Change in insulin at 30 min were compared with baseline insulin level showing no significant change between placebo and turmeric group. Fasting insulin after 3-weeks consumption of turmeric did not show any significant change, but showed a larger effect size (0.08). Future research is essential to examine the turmeric powder supplement benefits over a long period of time in healthy adults and whether it is beneficial in preventing the occurrence of type 2 diabetes.
ContributorsOza, Namrata (Author) / Johnston, Carol (Thesis advisor) / Mayol-Kreiser, Sandra (Committee member) / Lespron, Christy (Committee member) / Arizona State University (Publisher)
Created2017
Description
Fish oil has been extensively researched for its protective effects on cognition. More recently, anthocyanins have also gained the attention of the medical community for their potential cognitive benefits. Maqui berries are one of the richest sources of anthocyanins known to science. While there are many randomized controlled trials (RCT) investigating the effects of fish oil and/or anthocyanins on cognition in various populations, there are no RCT that exclusively investigate the cognitive effects of these compounds in adults with Type 2 Diabetes (DM2). The purpose of this double-blinded, placebo-controlled RCT was to investigate the cognitive effects of maqui berry extract and fish oil supplements in adults with DM2 over the course of eight weeks. Adults with DM2 (n=29) were recruited by the researchers and randomized to either Group A or Group B. Because the study is ongoing, it is unknown which group received the intervention. The study used the Stroop Test and Trail Making Test (TMT) to measure cognition at baseline, 4 weeks, and 8 weeks. Anthropometrics, blood glucose, and hemoglobin A1C were also taken at these time points. Sixteen female participants were included in the final analysis. Neither group showed significant improvements in the cognitive tests. However, in Group A, the effect sizes were large for the change in Trail-Making Test A (0.167), Trail Making Test B (0.261), and Trail Making Test B minus A (0.296) scores. In Group A, the change in Trail Making Test B minus A scores between baseline and week 4, and between baseline and week 8 was significant (p=0.053) and produced a large effect size (0.258). The results suggest that fish oil and maqui berry extract may improve cognition in adults with DM2, but further studies with larger sample sizes are needed.
ContributorsDeimeke, Allyson (Author) / Johnston, Carol (Thesis advisor) / Grant, Shauna (Committee member) / Sweazea, Karen (Committee member) / Arizona State University (Publisher)
Created2023
Description
Low water intake and underhydration are public health issues that may increase risk for diseases such as Type 2 Diabetes Mellitus. Studies suggest that high vasopressin (AVP) levels associated with low water intake may contribute to hyperglycemia. This study explored the physiological system by which AVP impairs glucose regulation through a single-blind randomized, counterbalanced, crossover design. This is a pilot and feasibility study of AVP infusion at increasing incremental rates, which was completed to determine the rate of infusion for the cross-over study. Participants completed a control and experimental trial. The experimental trial included a 3-hour AVP infusion and a 2-hour euglycemic-hyper insulinemic clamp at the end of the first hour versus control of 0.9% sodium chloride replacing AVP. In both trials, blood samples were taken every 5 minutes to measure glucose, as well as 7 other time points of insulin infusion. Two participants completed the pilot (47.5±3.5 years, 172.5 ±7.5cm, 82.5±17.7kg, 27.5±3.5 kg/m2, 5.1±0.64% HbA1c), and 3 participants completed the cross-over study (49±1.7 years, 173.7±6.7cm, 80.4±150kg, 26.5±3.2kg/m2, 5.3±0.2% HbA1c), all females. The rate of AVP infusion for the cross-over study was 12.5 mU/min. Compared to the control, the AVP trial blood glucose trended higher towards the end of the experiment, as did glucose metabolism, plasma osmolality, and plasma volume. Blood pressure was slightly higher in the AVP trial versus the saline, while plasma sodium and potassium levels did not differ. Total plasma protein seemed higher in the saline trials than in the AVP trials. This study supports the notion that increased levels of vasopressin over time may increase blood glucose. This could lead to supplementation of type 2 diabetes interventions with increased water intake.
ContributorsAcri, Emily Suzanne (Author) / Kavouras, Stavros (Thesis advisor) / Johnston, Carol (Committee member) / Shepard, Christina (Committee member) / Arizona State University (Publisher)
Created2024