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- All Subjects: Intermittent Fasting
- Creators: Johnston, Carol
Description
Some cyanobacteria, referred to as boring or euendolithic, are capable of excavating tunnels into calcareous substrates, both mineral and biogenic. The erosive activity of these cyanobacteria results in the destruction of coastal limestones and dead corals, the reworking of carbonate sands, and the cementation of microbialites. They thus link the biological and mineral parts of the global carbon cycle directly. They are also relevant for marine aquaculture as pests of mollusk populations. In spite of their importance, the mechanism by which these cyanobacteria bore remains unknown. In fact, boring by phototrophs is geochemically paradoxical, in that they should promote precipitation of carbonates, not dissolution. To approach this paradox experimentally, I developed an empirical model based on a newly isolated euendolith, which I characterized physiologically, ultrastructurally and phylogenetically (Mastigocoleus testarum BC008); it bores on pure calcite in the laboratory under controlled conditions. Mechanistic hypotheses suggesting the aid of accompanying heterotrophic bacteria, or the spatial/temporal separation of photosynthesis and boring could be readily rejected. Real-time Ca2+ mapping by laser scanning confocal microscopy of boring BC008 cells showed that boring resulted in undersaturation at the boring front and supersaturation in and around boreholes. This is consistent with a process of uptake of Ca2+ from the boring front, trans-cellular mobilization, and extrusion at the distal end of the filaments (borehole entrance). Ca2+ disequilibrium could be inhibited by ceasing illumination, preventing ATP generation, and, more specifically, by blocking P-type Ca2+ ATPase transporters. This demonstrates that BC008 bores by promoting calcite dissolution locally at the boring front through Ca2+ uptake, an unprecedented capacity among living organisms. Parallel studies using mixed microbial assemblages of euendoliths boring into Caribbean, Mediterranean, North and South Pacific marine carbonates, demonstrate that the mechanism operating in BC008 is widespread, but perhaps not universal.
ContributorsRamírez-Reinat, Edgardo L (Author) / Garcia-Pichel, Ferran (Thesis advisor) / Chandler, Douglas (Committee member) / Farmer, Jack (Committee member) / Neuer, Susanne (Committee member) / Arizona State University (Publisher)
Created2010
Description
Circadian misalignments in terms of eat and sleep cycles, common occurrences among college students, are linked to adverse health outcomes. Time-restricted feeding, a form of intermittent fasting, may offer an exciting, non-pharmacologic approach to improve the health of this population by restricting eating to feeding windows that align with circadian biology. This study aims to fill a gap in the literature regarding the effect of early time-restricted feeding (eTRF) on college students, particularly in regard to diet quality, diet self-efficacy, and sleep quality. To test the hypothesis that eTRF would lead to an increase in all three variables, a 4-wk randomized-controlled, parallel arm trial was conducted. Thirty-five healthy college students were randomly assigned to one of two groups: the intervention group (TRF) was instructed to adhere to an 8-h feeding window aligned with the light cycle (9 am to 5 pm), and the control group (CON) was instructed to adhere to a 12-h feeding window typical of college students (10 am to 10pm). The eTRF diet was consumed ad libitum, and the participants were not instructed to avoid compensatory hyperphagia. The results showed a strong, reverse effect of eTRF on diet quality: fasting had a highly significant association with decreased diet quality. The results suggest that, under free-living conditions, college students practicing eTRF are more likely to compensate for prolonged fasting with unhealthy eating and snacking.
ContributorsGonzalez, Valeria Isabel (Author) / Johnston, Carol (Thesis director) / Hundley, Amanda (Committee member) / Edson College of Nursing and Health Innovation (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description
Mood disorders are prevalent within the college student population, increasing the potential for poor academic performance among those students. Intermittent fasting, particularly time-restricted feeding (TRF) regimens, have shown promising results associated with improvements in health outcomes related to weight loss, cardiovascular health, glucose and insulin regulation, and breast cancer; however, very limited research exits for the impact on mood states. The objective of this eight-week randomized, controlled trial was to examine the effects of a daily fasting regimen of 18 hours (six hour feeding window), compared to a daily fasting regimen of eight hours (16 hour feeding window), on the mood state of healthy college students attending Arizona State University or University of Arizona. Twenty nine students were recruited and randomized into the TRF group (n = 16) following a 16-hour fast or the control (CON) group (n = 13) following an eight-hour fast. Participants in each group were instructed to consume their first meal within an hour of waking, which would then begin their assigned feeding window. Participants were also allowed one ‘cheat day’ per week in which they were not required to follow their assigned fasting protocol, otherwise no additional dietary instructions were given; participants were permitted to consume food and beverages ad libitum throughout their feeding window. Mood state was assessed at baseline, week four, and week eight using the Profile of Mood States questionnaire and the GAD-7, specific to generalized anxiety. Of the initial 29 participants recruited, 18 completed the trial (TRF group n = 8; CON group n = 10). Data were reported through week four only, due to inconsistencies with week eight data as a result of the COVID-19 pandemic. The mood state measures did not show any statistically significant changes after four weeks. The results of this study suggest that a TRF regimen of 18 hours does not significantly impact overall or individual mood states among college students.
ContributorsChondropoulos, Kelly Nicole (Author) / Johnston, Carol (Thesis advisor) / Shepard, Tina (Committee member) / Alexon, Christy (Committee member) / Arizona State University (Publisher)
Created2021
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
Background: College students face a particularly high prevalence of body dissatisfaction and weight instability increasing the risk of being unhappy and having a poor quality of life. Time-restricted feeding, a type of intermittent fasting, has gained popularity recently for sustainable weight loss without the characteristic dietary restrictions of most fad diets. A limited number of randomized control trials have looked at the effects of time-restricted feeding in humans, but none have looked at how this dietary regimen impacts happiness and quality of life. Objective: The goal was to examine the effects of an 18-hour daily fasting regimen compared to an 8-hour daily fasting regimen on happiness and quality of life in college students in Arizona.
Methods: Participants included 29 healthy, non-smoking, non-vaping students attending college in Arizona between October 2020 to March 2021. Of the 16 participants allocated to the time-restricted feeding intervention, 8 completed the trial. Of the 13 participants allocated to the control group, 10 completed the trial. The eating window began within one hour of waking up with a 6-hour eating window for the intervention group and 16-hour window for the control group. They could do one cheat day per week. No dietary restrictions were enforced. Participants completed the Oxford Happiness Questionnaire and the WHOQOL-BREF quality of life questionnaire at baseline, week 4, and week 8. Week 8 data were not reported due to data collection changes and cancellations related to the new safety protocols for the COVID-19 pandemic.
Results: Quality of life related to social relationships improved significantly in the intervention group (p=0.026). There was a trend favoring the intervention group as well showing a possible improvement in happiness related to perceived energy levels (p=0.088). No other significant data were reported.
Conclusion: Adherence to an 18-hour time-restricted feeding regimen for 8 weeks may improve quality of life related to social relationships in college students in Arizona. The results of this trial do not suggest a significant impact on overall quality of life or happiness in this population.
ContributorsDe León, Anateresa (Author) / Johnston, Carol (Thesis advisor) / Shepard, Christina (Committee member) / Grant, Shauna (Committee member) / Arizona State University (Publisher)
Created2021
Description
ABSTRACT
Background. College students’ modifiable health behaviors, including unhealthful eating patterns, predispose them to risk for future cardiometabolic conditions.
Purpose. This novel 8-week randomized control parallel-arm study compared the effects of a daily 18-hour Time-Restricted Feeding protocol vs. an 8-hour fast on diet quality in college students. Secondary outcomes were resting morning blood pressure, biomarkers of glucose regulation, biomarkers of lipid metabolism, and anthropometric measures.
Methods. Eighteen healthy college students (age = 23 ± 4 years; BMI = 23.2 ± 2.3 kg/m2; MET = 58.8 ± 32.9 min/wk) completed this study. Participants were randomized to a daily 18-hour fasting protocol (Intervention; n = 8) or a daily 8-hour fasting protocol (Control; n = 10) for eight weeks. One ‘cheat’ day was permitted each week. Outcomes were measured at weeks 0 (baseline), 4, and 8. A non-parametric Mann Whitney U test was used to compare the week 4 change from baseline between groups. Statistical significance was set at p≤0.05.
Results. Diet quality (p = 0.030) and body weight (p = 0.016) improved from baseline to week 4 for the INV group in comparison to the CON group. The data suggest these improvements may be related to reductions in snacking frequency and increased breakfast consumption. Fasting blood glucose and hip circumference tended to improve for the INV group in comparison to the CON group (p = 0.091 and p = 0.100). However, saturated fat intake tended to increase in the INV group in comparison to the CON group (p = 0.064). Finally, there were no treatment differences between groups (p>0.05) for the 4-week change in total calories, dietary vitamin C, added sugars, resting systolic blood pressure, resting diastolic blood pressure, insulin, homeostatic model assessment for insulin resistance (HOMA-IR), low-density lipoprotein (LDL) cholesterol, triglycerides, high-density lipoprotein (HDL) cholesterol, waist circumference, or MET.
Conclusion. These data, although preliminary, suggest that the 18-hour fasting protocol was effective for improving diet quality and reducing weight in comparison to the 8-hour fasting protocol in healthy college students. Future intervention trials will need to confirm these findings and determine the long-term relevance of these improvements for health outcomes.
Background. College students’ modifiable health behaviors, including unhealthful eating patterns, predispose them to risk for future cardiometabolic conditions.
Purpose. This novel 8-week randomized control parallel-arm study compared the effects of a daily 18-hour Time-Restricted Feeding protocol vs. an 8-hour fast on diet quality in college students. Secondary outcomes were resting morning blood pressure, biomarkers of glucose regulation, biomarkers of lipid metabolism, and anthropometric measures.
Methods. Eighteen healthy college students (age = 23 ± 4 years; BMI = 23.2 ± 2.3 kg/m2; MET = 58.8 ± 32.9 min/wk) completed this study. Participants were randomized to a daily 18-hour fasting protocol (Intervention; n = 8) or a daily 8-hour fasting protocol (Control; n = 10) for eight weeks. One ‘cheat’ day was permitted each week. Outcomes were measured at weeks 0 (baseline), 4, and 8. A non-parametric Mann Whitney U test was used to compare the week 4 change from baseline between groups. Statistical significance was set at p≤0.05.
Results. Diet quality (p = 0.030) and body weight (p = 0.016) improved from baseline to week 4 for the INV group in comparison to the CON group. The data suggest these improvements may be related to reductions in snacking frequency and increased breakfast consumption. Fasting blood glucose and hip circumference tended to improve for the INV group in comparison to the CON group (p = 0.091 and p = 0.100). However, saturated fat intake tended to increase in the INV group in comparison to the CON group (p = 0.064). Finally, there were no treatment differences between groups (p>0.05) for the 4-week change in total calories, dietary vitamin C, added sugars, resting systolic blood pressure, resting diastolic blood pressure, insulin, homeostatic model assessment for insulin resistance (HOMA-IR), low-density lipoprotein (LDL) cholesterol, triglycerides, high-density lipoprotein (HDL) cholesterol, waist circumference, or MET.
Conclusion. These data, although preliminary, suggest that the 18-hour fasting protocol was effective for improving diet quality and reducing weight in comparison to the 8-hour fasting protocol in healthy college students. Future intervention trials will need to confirm these findings and determine the long-term relevance of these improvements for health outcomes.
ContributorsMayra, Selicia (Author) / Johnston, Carol (Thesis advisor) / Sears, Dorothy (Committee member) / Swan, Pamela (Committee member) / Sweazea, Karen (Committee member) / Wharton, Christopher (Christopher Mack), 1977- (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
Intermittent Fasting (IF) is defined as a cyclical eating pattern where an individual will fast for a specific increment of time, followed by caloric intake periods. Fasting is a crucial part of our ancestors’ adaptation to the stresses of famine in order to maintain mental acuity and physical abilities during food deprivation. IF influences physiological changes such as: triggers protective metabolic pathways, increases metabolic flexibility and resilience, promotes DNA repair and autophagy, increases microbiome diversity and restores the natural cyclical fluctuations of the gut, increases BDNF expression in mood regulating neuronal circuits, and enhances synaptic plasticity of the brain. Research on the underlying causes of mood disorders has linked impairments in neuroplasticity and cellular resilience to this pathophysiology, which fasting could mitigate. Depression and anxiety are reported as the top impediments to academic performance. Thus, an easily implemented treatment such as intermittent fasting may be an option for combating impaired mental health in college students. This research study tested time restricted feeding (TRF) and its impact on mood states. It was hypothesized that: if college students follow a time restricted feeding pattern, then they will be less moody due to TRF’s effects on the metabolism, brain, and gut. The study consisted of 11 college students: 5 following a four-week adherence to TRF (8am-4pm eating window) and 6 in the control group. The POMS questionnaire was used to measure mood states. The participants height, weight, BMI, body fat %, and POMS scores were tested at the beginning and end of the 4 week intervention. The results were as follows: weight p=0.112 (statistical trend), BMI p=0.058 (nearly significant), body fat % p=0.114 (statistical trend), POMS p=0.014 (statistically significant). The data suggests that following a TRF eating pattern can decrease moodiness and improve mood states.
ContributorsFoley, Sadie Jean (Author) / Johnston, Carol (Thesis director) / Shepard, Christina (Committee member) / Department of Management and Entrepreneurship (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
Oral health encompasses a wide variety of conditions with two of the primary conditions being enamel degradation and periodontal disease. These ailments are intertwined and are known to be prevented by a combination of good oral hygiene and a balanced diet. Despite this, incidence rates of oral health conditions in both high and low-and-middle income countries remain high. Periodontal disease prevention is of particular relevance due to its correlation with cardiovascular disease. One highly popular diet that could serve as an alternative strategy in combatting these oral health conditions is intermittent fasting. Intermittent fasting has shown promise in decreasing systemic inflammation and blood glucose levels, both of which are correlated with periodontal disease and enamel degradation. To explore this relationship between intermittent fasting and oral health a 9-week experimental protocol with 4 randomly established groups was completed. These groups included ad libitum high and low-fat groups, and time restricted feeding high and low-fat groups. After the 9-week protocol the mice were sacrificed, and their intact jaws and gingiva tissue were isolated. Three primary methods were used to quantify the effects of intermittent fasting on oral health: comparing the enamel density between groups, comparing the alveolar bone recession between groups, and comparing the gene expression of periodontal disease markers between groups. Body composition and fasting blood glucose levels of the mice were also quantified. We found that the fasting groups had lower average fasting blood glucose levels and maintained a more physiologically ideal body composition. Despite this, the oral health analyses did not have any consistent significant results. The results of this study suggest that despite intermittent fasting’s role in blood glucose levels and body composition regulation, it has minimal effects on enamel degradation and periodontal disease development.
ContributorsCollis, Graham (Author) / Jakiche, Michael (Co-author) / Roberts, Joseph (Thesis director) / Johnston, Carol (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2024-05
Description
Time restricted eating (TRE) is an increasingly popular diet strategy that has shown promise for weight loss and improving metabolic health. The impact of TRE on bone health has not been extensively studied, and the goal of this experiment is to provide more insight into this subject. 32 10-week old female mice were randomly assigned to 4 groups (n = 8). These included low fat diet fed ad-libitum, low fat time restricted feeding (TRF), high fat diet fed ad-libitum, and high fat TRF. The mice adhered to these diets for 9 weeks, with the TRF groups having access to food for 8 hours per day until the sacrifice. At nine weeks, the TRF mice had significantly lowered body weight, improved body composition, and a lower fasting blood glucose. The TRF groups also experienced significant improvements in the trabecular bone density of the tibia, femur, and L3 vertebral body. This was found alongside reductions in osteoclast count and activity in the TRF mice. When compared to a baseline group of 10-week old mice, it was found that the TRF group had significantly less bone loss relative to the ad-libitum fed mice. Improvements in metabolic health, gut barrier function, and inflammation may have all contributed to the observed improvements in bone health. These results reveal a promising and previously unrecognized dietary tool to improve bone health and counteract age-related bone loss.
ContributorsJakiche, Michael (Author) / Collis, Graham (Co-author) / Roberts, Joseph (Thesis director) / Johnston, Carol (Committee member) / Barrett, The Honors College (Contributor) / Department of Physics (Contributor)
Created2024-05