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- Genre: Masters Thesis
- Creators: Johnston, Carol
- Member of: ASU Electronic Theses and Dissertations
- Resource Type: Text
Description
Introduction: A diet high in fermented, oligio-, di-, monosaccharide, and polyols
(FODMAP) has been shown to exacerbate symptoms of irritable bowel syndrome
(IBS). Previous literature has shown significant improvement in IBS symptoms after
adherence to a low FODMAP diet (LFD). However, dietary adherence to the LFD is
difficult with patients stating that information provided by healthcare providers
(HCPs) is generalized and nonspecific requiring them to search for supplementary
information to fit their needs. Notably, studies that have used a combination of
online and in-person methods for treatment have shown improved adherence to the
LFD. Objective: To determine whether a novel artificial intelligence (AI) dietary
mobile application will improve adherence to the LFD compared to a standard online
dietary intervention (CON) in populations with IBS or IBS-like symptoms over a 4-
week period. Methods: Participants were randomized into two groups: APP or CON.
The intervention group was provided access to an AI mobile application, a dietary
resource verified by registered dietitians which uses artificial intelligence to
individualize dietary guidance in real-time with the ability to scan menus and
barcodes and provide individuals with food scores based on their dietary preferences.
Primary measures included mobile app engagement, dietary adherence, and
manifestation of IBS-like symptoms. Baseline Results: A total of 58 participants
were randomized to groups. This is an ongoing study and this thesis details the
methodology and baseline characteristics of the participants at baseline and
intervention start. Validation of the application could improve the range of offerings
for lifestyle diseases treatable through dietary modification.
(FODMAP) has been shown to exacerbate symptoms of irritable bowel syndrome
(IBS). Previous literature has shown significant improvement in IBS symptoms after
adherence to a low FODMAP diet (LFD). However, dietary adherence to the LFD is
difficult with patients stating that information provided by healthcare providers
(HCPs) is generalized and nonspecific requiring them to search for supplementary
information to fit their needs. Notably, studies that have used a combination of
online and in-person methods for treatment have shown improved adherence to the
LFD. Objective: To determine whether a novel artificial intelligence (AI) dietary
mobile application will improve adherence to the LFD compared to a standard online
dietary intervention (CON) in populations with IBS or IBS-like symptoms over a 4-
week period. Methods: Participants were randomized into two groups: APP or CON.
The intervention group was provided access to an AI mobile application, a dietary
resource verified by registered dietitians which uses artificial intelligence to
individualize dietary guidance in real-time with the ability to scan menus and
barcodes and provide individuals with food scores based on their dietary preferences.
Primary measures included mobile app engagement, dietary adherence, and
manifestation of IBS-like symptoms. Baseline Results: A total of 58 participants
were randomized to groups. This is an ongoing study and this thesis details the
methodology and baseline characteristics of the participants at baseline and
intervention start. Validation of the application could improve the range of offerings
for lifestyle diseases treatable through dietary modification.
ContributorsRafferty, Aaron (Author) / Johnston, Carol (Thesis advisor) / Hall, Richard (Committee member) / Fitton, Renee (Committee member) / Arizona State University (Publisher)
Created2020
Description
The popularity of intermittent fasting has grown in recent years and is a commonly discussed diet topic on the internet and social media. Time-restricted feeding (TRF) is one particular intermittent fasting regime that allows participants to pick windows of time per day in which they can eat or fast. While current randomized controlled trials show positive effects of TRF on weight loss, body composition, glucose, insulin, and blood pressure, there is a gap in the literature of the its effect on cognition although animal studies suggest a positive effect. The purpose of this 8-week randomized controlled trial was to investigate the effect of 18-hour time-restricted feeding on healthy, Arizona State university students. Students (n= 29) were recruited by the research team and were randomized to either an 18-hour intervention (INV) group or an 8-hour control (CON) group. INV participants were instructed to consume food within the first hour of waking and cease their eating period after 6 hours to begin their 18-hour fast. Participants were not given any other dietary restrictions and were allowed to eat ad libitum during their eating periods. Cognitive tests (Stroop Test and Trail Making Test) and blood draws were taken at baseline, week 4, and week 8. The present study demonstrated high attrition, with 7 participants dropping out of the study after their baseline visit. Interruption of the COVID-19 pandemic also impacted the data analysis, with the removal of week 8 data. Despite limitations, statistically significant differences between the INV group and CON group were seen in the Trail Making Test B at week 4 (p= 0.031). Statistically significant differences were not seen in any of the other cognitive outcomes measured (Stroop Test, Trail Making Test A, serum BDNF, serum ketones). However, a significant inverse relationship was seen between serum ketones and Trail Making Test B. In conclusion, this study suggests that TRF may have a favorable effect on cognitive acuity among university students.
ContributorsKravat, Natalie (Author) / Johnston, Carol (Thesis advisor) / Gu, Haiwei (Committee member) / Sears, Dorothy (Committee member) / Arizona State University (Publisher)
Created2021
Description
Background: Research has found that nearly a quarter of the American population follows a gluten-free diet in some capacity, while only about 1% of the population is diagnosed with celiac disease. Although the amount of research-based evidence supporting any health benefits of a gluten-free diet in an individual without a gluten- related disorder is limited, the number of people claiming to follow a gluten-free diet continues to rise. Also, despite an increasing belief that gluten is harmful for health, the potentially undesirable effects of gluten substitutions used in gluten-free foods are largely unknown. Due to the protein network encapsulating starch granules, gluten is thought to lengthen the amount of time needed during starch digestion, thereby reducing postprandial glycemia. Therefore, it is predicted that breads containing gluten will produce a lower glycemic response compared to gluten-free breads. Aim: The aim of this study was to investigate the glycemic response of gluten-free bread made with different types of flour compared to bread made with gluten-containing wheat flour. Methods: This study involved a 3-week, randomized, single blind crossover study in which 17 healthy individuals were asked to consume a different type of bread each week, 2 of which were gluten-free. Blood glucose was taken by finger prick at fasting as a baseline measurement, then for 2 hours after bread consumption in 30-minute increments. Results: Across the three groups, there was no significant difference in iAUC values after 120 minutes (p=0.192 ). The greatest mean was seen in the gluten-containing bread (145.3 ± 82.6), then the gluten-free bread made with rice flour (125.5 ± 62.8), and lastly the gluten-free bread made with potato and fava bean flour (112.4 ± 64.5). Conclusion: The inconsistent results of this study compared to previous, similar studies suggests that the postprandial glycemic response of gluten-free products can not be generalized as a whole, but instead is dependent on the type of product and the ingredients used to replace the gluten. Although the results did not show a significant difference, it does argue against the belief that gluten-free products are invariably better for health in the general, non-gluten sensitive population.
ContributorsWaznik, Lauren LaRue (Author) / Johnston, Carol (Thesis advisor) / Mayol-Kreiser, Sandra (Committee member) / Dixon, Kathleen (Committee member) / Arizona State University (Publisher)
Created2019
Description
Background: Individuals in the general populations with a known gluten disorder is believed to be 6% and it is unclear why the gluten free diet (GFD) has risen sharply (28%) in recent years. However, science has revealed that gluten can cause colonic changes in those undiagnosed with a known gluten disorder. The ramifications of these changes are unknown. Three common ingredients found in gluten free products, such as pasta, are corn quinoa and rice. Evidence from the scientific literature has shown that corn and quinoa can produce more colonic hydrogen than refined wheat and rice, indicating that corn and quinoa have a reduced glycemic effect. Since rice and wheat have similar glycemic responses, corn and quinoa pastas would be expected to have a lower glycemic response than rice and wheat pasta
.
Aim The aim of his study was to examine the glycemic response to three different types of pasta: wheat, rice and corn. Breath hydrogen, assessment of mood states, blood glucose and insulin were collected after ingestion of these pastas to determine the glycemic effects of these foods.
Methods: A double blinded crossover study design was utilized on a group of healthy individuals, and the test meals of wheat, rice and combinations of rice/corn, and corn/quinoa pastas were consumed one week apart in random order. Collections of fasting venous blood samples for insulin analysis, capillary blood from a finger stick for glucose analysis, breath hydrogen samples and satiety scales were used for glycemic response and mood states were collected prior to the meal (baseline) and then again after ingestion of the test meals. Attempts were made to explore the glycemic response of these test meals in relation to mood states.
Results: The glucose response showed no significant difference at baseline (p = .683) among all groups and no significant differences were seen post treatment at 30 minutes (p = .875). However, after 60 minutes all of the glucose concentrations began to decline except for the rice pasta which peaked at 90 minutes and the wheat pasta gave the most sustained decrease. The AUC glucose values showed no significant difference at both 120 (p=0.196) and 240 (p=0.734) minutes but with wheat pasta producing the lowest mean value. The POMS scores showed no significant differences between groups over time (p=.239) but the wheat group produced the highest score (worsening moods states).
Conclusion: These results indicate that the formulation and processing of gluten free pastas may affect the rate and absorption and the subsequent glycemic response after the consumption of these foods. Whether or not wheat contains an ingredient that slows absorption and/or negatively affects mood remains undetermined warrants future research in this area.
.
Aim The aim of his study was to examine the glycemic response to three different types of pasta: wheat, rice and corn. Breath hydrogen, assessment of mood states, blood glucose and insulin were collected after ingestion of these pastas to determine the glycemic effects of these foods.
Methods: A double blinded crossover study design was utilized on a group of healthy individuals, and the test meals of wheat, rice and combinations of rice/corn, and corn/quinoa pastas were consumed one week apart in random order. Collections of fasting venous blood samples for insulin analysis, capillary blood from a finger stick for glucose analysis, breath hydrogen samples and satiety scales were used for glycemic response and mood states were collected prior to the meal (baseline) and then again after ingestion of the test meals. Attempts were made to explore the glycemic response of these test meals in relation to mood states.
Results: The glucose response showed no significant difference at baseline (p = .683) among all groups and no significant differences were seen post treatment at 30 minutes (p = .875). However, after 60 minutes all of the glucose concentrations began to decline except for the rice pasta which peaked at 90 minutes and the wheat pasta gave the most sustained decrease. The AUC glucose values showed no significant difference at both 120 (p=0.196) and 240 (p=0.734) minutes but with wheat pasta producing the lowest mean value. The POMS scores showed no significant differences between groups over time (p=.239) but the wheat group produced the highest score (worsening moods states).
Conclusion: These results indicate that the formulation and processing of gluten free pastas may affect the rate and absorption and the subsequent glycemic response after the consumption of these foods. Whether or not wheat contains an ingredient that slows absorption and/or negatively affects mood remains undetermined warrants future research in this area.
ContributorsSnyder, Darren (Author) / Johnston, Carol (Thesis advisor) / Ohri-Vachaspati, Punam (Committee member) / Lespron, Christy (Committee member) / Arizona State University (Publisher)
Created2015
Description
There is a considerable amount of research stating that vegetarian diets have an alkalizing effect while the typical western diet is acid-forming. There is substantial evidence regarding the health benefits of an alkaline diet. Although vegetarian diets demonstrate the ability to foster these health benefits, many people are still not willing to adopt a completely vegetarian diet. PURPOSE: To evaluate the effect of following a vegan diet two or three days per week on acid-base balance in a healthy college student population aged 18-30. METHODS: In a one-week interventional design, 23 people were randomly assigned to follow a vegan diet 2 days per week (VEG2;n=7), 3 days per week(VEG3;n=8), or 7 days per week (VEG7;n=8). Urine pH and dietary PRAL were assessed in each group at baseline and after the one-week intervention. RESULTS: There was no significant difference in urinary pH between the three groups (p=0.12). The change in PRAL values after the dietary intervention was different between the 3 groups (p=0.03). CONCLUSION: Adherence to a vegan diet 2 or 3 days per week did not show a significant change in urinary pH or PRAL.
ContributorsCosgrove, Kelly (Author) / Johnston, Carol (Thesis advisor) / Sweazea, Karen (Committee member) / Mayol-Kreiser, Sandra (Committee member) / Arizona State University (Publisher)
Created2015
Description
Diabetes is the 7th leading cause of death globally. In 2018, 34.2 million Americans had type 2 diabetes. Many symptoms of diabetes are similar to those of scurvy or vitamin C deficiency. Vitamin C marginality and inadequacy are more prevalent in Type 2 Diabetes/prediabetes than with normal glucose tolerance. Intracellular vitamin C inadequacy is suspected due to competition between dehydroascorbic acid and glucose at GLUT 1 and 3 cellular receptors. Erythrocyte osmotic fragility is noted in Gulo -/- knockout mice unable to synthesize endogenous vitamin C. The ascorbate deficient red blood cells presented with low cytoskeletal B-spectrin, spherocyte appearance, and impaired deformability. This cross-sectional study investigated the relationships between diabetes status, erythrocyte osmotic fragility, and serum vitamin C status. Participants were aged 18-65, non-smoking, reported no unresolved health complications, and denied prior vitamin C supplementation. Those with T2D indicated diagnosis of >1 year. All participants provided written informed consent and the study was approved by the local Institutional Review Board in January 2021. Participants provided one fasted blood sample. Erythrocyte osmotic fragility was measured via UV/Vis spectrophotometry with various concentrations of sodium chloride (0.85% - 0.10%) to induce osmotic stress. In addition, plasma was extracted and mixed 1:1 with 10% (w/v) metaphosphoric acid in 2 mmol/L disodium EDTA and centrifuged. The supernatant was stored at -80°C until analysis with isocratic reverse-phase UV-HPLC separation.
Participant characteristics did not differ significantly between groups apart from age (p< 0.01) and HbA1c (p=0.002). Data are presented for adults with T2D (n=14; 36% female; 55.5±8.2 y; 31.5±9.0 kg/m2; HbA1c: 7.4±1.9%; plasma vitamin C: 36.0±12.2 uM) and without T2D (n=16; 69% female; 38.7±13.5 y; 26.8±6.6 kg/m2; A1c: 5.4±0.3%; plasma vitamin C: 34.8±10.9uM). Erythrocyte osmotic fragility was significantly elevated (+4.4% hemolysis) in adults without T2D at 0.35% saline (p=0.039). Greater VC status (>30 uM) was associated with lower hemolysis at 0.35% NaCl (p=0.031). Erythrocyte osmotic stability was linked to greater vitamin C intake at 0.20% saline in those without T2D (p =0.019).
In this pilot study, vitamin C status did not differ significantly by diabetes status. Vitamin C status was directly linked to erythrocyte osmotic stability in adults without T2D.
ContributorsLundy, Ciara Cheyanne (Author) / Johnston, Carol (Thesis advisor) / Sweazea, Karen (Committee member) / Alexon, Christy (Committee member) / Arizona State University (Publisher)
Created2022
Description
Food waste is gaining considerable attention from researchers in terms of its sources, its causes, and its potential effects on the environment, economy, and population health. To date, few instruments exist that allow researchers to measure food waste at the household level in reliable ways. This study aimed to assess the reliability of a newly developed self-assessment tool to measure household food waste, among participants living in Mexico. The survey tool consisted of 11 items which ask participants (N = 22) to estimate the amount of food per category that generally gets thrown away instead of eaten in the average week. Two tests of reliability were conducted, including Cronbach's Alpha for test-retest reliability, and Intra-class Correlation for internal reliability. Results varied across food categories evaluated by individual items. Items related to fresh fruit and bread products did not show reliability when testing for internal reliability or test-retest reliability. Fresh vegetables, meat and poultry products, meat alternative products, fish and seafood products, leftovers, and shelf stable foods were shown to be reliable when testing Cronbach's alpha and ICC. However, dairy products, eggs and frozen foods were inconclusive when testing for reliability. The study suggests future testing with larger sample sizes should be conducted to demonstrate reliability of the food waste self-assessment tool.
ContributorsLeone, Bryanna (Author) / Wharton, Christopher (Thesis advisor) / Shepard, Christina (Committee member) / Johnston, Carol (Committee member) / Arizona State University (Publisher)
Created2022
Description
Background. Research suggests that non-O blood types are at an increased risk of thrombosis and related health complications in cardiovascular disease (CVD). This is due in part to higher concentrations of von Willebrand factor (VWF), an important factor involved in blood clotting. Objective. The purpose of this study was to examine the effects of a vegetarian-like diet on blood coagulation and other health parameters in adults with type A blood compared to type O blood over a four week intervention. Given the lack of previous research on blood type and diet, it was hypothesized that no difference in blood coagulation would be observed. Design. This study was a randomized, parallel arm, dietary intervention using healthy, omnivorous adults with blood types A and O. A total of 39 subjects completed the study. Subjects were randomized into two groups: a vegetarian-like diet group made up of 12 type As and 12 type Os and an omnivorous control diet group made up of 11 type As and 12 type Os. At weeks 0 and 4, fasting blood was drawn and analyzed for prothrombin time (PT), activated partial thromboplastin time (APTT), von Willebrand factor (VWF), total cholesterol, LDL, HDL, triglycerides, and CRP. In addition, subjects were weighed and filled out a FFQ at weeks 0 and 4. Results. After adhering to a vegetarian-like diet for four weeks, type Os had a significant increase in PT (+0.24±0.32 sec/ p=0.050), whereas type As saw no significant change. There was a trend of weight loss for type Os in the vegetarian-like diet group (-1.8±2.6 lb/ p=0.092) and significant weight loss for type As (-0.9±2.1 lb/ p=0.037). Both blood types O and A experienced significant decreases in BMI (-0.3±0.4/ p=0.092 and -0.2±0.3/ p=0.037, respectively). No change was seen in APTT, VWF, total cholesterol, LDL, HDL, triglycerides, or CRP. Conclusion. Type Os saw an increase in PT, perhaps indicating a reduction in risk of thrombosis and its related health complications. Type As were less responsive to the dietary intervention and may require more rigid dietary guidelines or a longer time on such a diet to see the benefits.
ContributorsBrown, Jennifer (Author) / Johnston, Carol (Thesis advisor) / Martin, Keith (Committee member) / Shepard, Christina (Committee member) / Arizona State University (Publisher)
Created2013
Description
The medicinal use of vinegar dates to ancient times, and empirical evidence has mounted over the past several decades supporting health benefits from vinegar ingestion, including reductions in blood glucose, blood pressure, and blood cholesterol. Additionally, although clinical trial data are mixed, there are several reports demonstrating reductions in body mass and fat mass with daily vinegar ingestion. This blinded, randomized placebo-controlled trial examined the impact of daily vinegar ingestion on anthropometric measures in healthy young adults recruited from a campus population. Participants (n=28; aged 25.8±7.0 y; body mass index [BMI] > 23 kg/m2) were stratified by age, sex, and BMI and randomly assigned to the liquid [VIN] or pill [CON] groups. VIN participants diluted 2 tablespoons of red wine vinegar (750 mg acetic acid; Pompeian Inc.) in 8-12 ounces of water to drink with food at mealtime twice daily. CON participants consumed 1 vinegar pill daily (22.5 mg acetic acid; Spring Valley). All participants provided written consent for this IRB approved trial. The study lasted four weeks, and anthropometric measurements were conducted in a fasted state at weeks 0 and 4. Study adherence varied slightly (90±17% and 100±14% for VIN and CON respectively, p=0.029); hence, adherence was controlled for in all analyses. Changes in BMI (-0.1±0.5 and +0.1±0.3 kg/m2, p=0.127) and body weight (-0.3±1.4 and +0.1±1.1 kg, p=0.158) did not differ significantly between VIN and CON groups, respectively. However, both waist circumference and percent body fat were reduced significantly for VIN participants in comparison to CON participants (-0.5±1.3 vs. +0.6±2.4 cm [p=0.026]and -0.4±0.7 vs. +0.3±1.0% [p=0.045]. Although the observed differences between groups are modest, the study was short in duration and this protocol did not apply energy restriction or exercise interventions, suggesting a possible benefit of vinegar ingestion on adiposity.
ContributorsMeyer, Lexie Rae (Author) / Johnston, Carol (Thesis advisor) / Alexon, Christy (Committee member) / Grant, Shauna (Committee member) / Arizona State University (Publisher)
Created2024