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ABSTRACT Vitamin C plays an important role in fatty acid metabolism because it is required for carnitine synthesis. Vitamin C has been shown to have an inverse relationship with weight and body fat percent in a number of studies. However, there has been limited research exploring the relationship between vitamin

ABSTRACT Vitamin C plays an important role in fatty acid metabolism because it is required for carnitine synthesis. Vitamin C has been shown to have an inverse relationship with weight and body fat percent in a number of studies. However, there has been limited research exploring the relationship between vitamin C status and fat oxidation. This cross-sectional study investigates the relationship between plasma vitamin C and fat oxidation in 69 participants and between plasma vitamin C and body fatness in 82 participants. Participants were measured for substrate utilization via indirect calorimetry while at rest and measured for body fatness via DEXA scan. Participants provided a single fasting blood draw for analysis of plasma vitamin C. Results did not show a significant association between vitamin C and fat oxidation while at rest, therefore the data do not support the hypothesis that vitamin C status affects fat oxidation in a resting state. However, a significant inverse association was found between vitamin C and both total body fat percent and visceral fat.
ContributorsObermeyer, Lindsay (Author) / Johnston, Carol (Thesis advisor) / Hall, Rick (Committee member) / Swan, Pamela (Committee member) / Arizona State University (Publisher)
Created2014
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ABSTRACT

Asthma is a high-stress, chronic medical condition; 1 in 12 adults in the United States combat the bronchoconstriction from asthma. However, there are very few strong studies indicating any alternative therapy for asthmatics, particularly following a cold incidence. Vitamin C has been proven to be effective for other high-stress

ABSTRACT

Asthma is a high-stress, chronic medical condition; 1 in 12 adults in the United States combat the bronchoconstriction from asthma. However, there are very few strong studies indicating any alternative therapy for asthmatics, particularly following a cold incidence. Vitamin C has been proven to be effective for other high-stress populations, but the asthmatic population has not yet been trialed. This study examined the effectiveness of vitamin C supplementation during the cold season on cold incidence and asthmatic symptoms. Asthmatics, otherwise-healthy, who were non-smokers and non-athletes between the ages of 18 and 55 with low plasma vitamin C concentrations were separated by anthropometrics and vitamin C status into two groups: either vitamin C (500 mg vitamin C capsule consumed twice per day) or control (placebo capsule consumed twice per day). Subjects were instructed to complete the Wisconsin Upper Respiratory Symptom Survey-21 and a short asthma symptoms questionnaire daily along with a shortened vitamin C Food Frequency Questionnaire and physical activity questionnaire weekly for eight weeks. Blood samples were drawn at Week 0 (baseline), Week 4, and Week 8. Compliance was monitored through a calendar check sheet. The vitamin C levels of both groups increased from Week 0 to Week 4, but decreased in the vitamin C group at Week 8. The vitamin C group had a 19% decrease in plasma histamine while the control group had a 53% increase in plasma histamine at the end of the trial, but this was not statistically significant (p>0.05). Total symptoms recorded from WURSS-21 were 129.3±120.7 for the vitamin C and 271.0±293.9, but the difference was not statistically significant (p=0.724). Total asthma symptoms also slightly varied between the groups, but again was not statistically significant (p=0.154). These results were hindered by the low number of subjects recruited. Continued research in this study approach is necessary to definitively reject or accept the potential role of vitamin C in asthma and cold care.
ContributorsEarhart, Kathryn Michelle (Author) / Johnston, Carol (Thesis advisor) / Sweazea, Karen (Committee member) / Lespron, Christy (Committee member) / Arizona State University (Publisher)
Created2015
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The common cold is a significant cause of morbidity world-wide, with human rhinovirus infections accounting for a majority colds suffered each year. While the symptoms of the common cold are generally mild and self-limiting, vulnerable populations such as individuals with asthma can experience severe secondary complications including acute asthma

The common cold is a significant cause of morbidity world-wide, with human rhinovirus infections accounting for a majority colds suffered each year. While the symptoms of the common cold are generally mild and self-limiting, vulnerable populations such as individuals with asthma can experience severe secondary complications including acute asthma exacerbation which can result in severe morbidity. Most human rhinovirus types utilize Intercellular Adhesion Molecule-1 (ICAM-1) as a receptor to enter cells and initiate infection. Expression of this cell-surface protein is elevated in the respiratory tract of asthma patients. The theoretical basis for this research is the observation that plasma measures of the soluble form of Intercellular Adhesion Molecule-1 (sICAM-1) decrease in response to vitamin C supplementation. As rhinovirus infection occurs in the upper respiratory tract, the primary aim of this study was to evaluate change in sICAM-1 concentration in nasal lavage of asthmatic individuals in response to vitamin C supplementation. Otherwise healthy asthmatic adults between the ages of 18-65 years who were not currently using steroidal nasal sprays, smoking, or actively training for competitive sports were recruited from a university community and surrounding area to participate in an 18-day double-blind randomized placebo-controlled supplement study with a parallel arm design. 13 subjects were stratified based on age, gender, BMI and baseline plasma vitamin C level to receive either 500 mg vitamin C twice daily (VTC, n=7) or placebo (PLC, n=6). Biochemical measures included nasal lavage sICAM-1, plasma sICAM-1, plasma histamine, and plasma vitamin C. Survey measures included Wisconsin Upper Respiratory Symptom Survey-21 to assess colds, Daytime Symptom Diary Scale to assess asthma symptoms, and measures of diet quality including a vitamin C food frequency questionnaire and Rapid Eating Assessment for Participants. No between group comparison of means reached significance (Mann-Whitney U test, p>0.05). Nasal lavage sICAM-1 levels were decreased in VTC group by 37% at study day 4, although this finding did not reach significance. Findings in this study can be used to develop future investigations into the response of nasal lavage sICAM-1 to vitamin C supplementation.
ContributorsGnant, Lindsay (Author) / Johnston, Carol (Thesis advisor) / Sweazea, Karen (Committee member) / Chang, Yung (Committee member) / Arizona State University (Publisher)
Created2014
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Vitamin C is a micronutrient with many important physiological roles. It can function as a reducing agent, a free radical scavenger, and an enzyme cofactor. Much research has examined the potential of vitamin C supplements to enhance exercise capacity in trained athletes; however, little is known regarding the effects of

Vitamin C is a micronutrient with many important physiological roles. It can function as a reducing agent, a free radical scavenger, and an enzyme cofactor. Much research has examined the potential of vitamin C supplements to enhance exercise capacity in trained athletes; however, little is known regarding the effects of vitamin C supplements on the promotion of leisure-time physical activity in the general population. This area deserves attention since 1/3 of Americans have below adequate vitamin C status, and since aversion to exercise, fatigue, and altered mood states are the earliest signs of poor vitamin C status. This study analyzed the effect of supplementing 500 mg twice daily of vitamin C on self-reported leisure-time activity levels and mood states in young men. Twenty-nine healthy, young men, aged 18-35 years, were stratified by age, BMI, smoking status, and plasma vitamin C concentrations and assigned to either a control (CON) or experimental group (VTC) for the 8-week randomized, double-blinded, parallel arm trial. Subjects were instructed to keep track of their leisure-time physical activity by filling out the validated Godin Leisure-Time Exercise Questionnaire weekly for the entire study. In addition, subjects took the self-administered Profile of Mood States (POMS) at baseline, week 4, and week 8 to observe mood states. Plasma vitamin C concentrations were analyzed at the initial screening, week 4, and week 8 of the study. Plasma vitamin C concentrations significantly differed by group at week 4 and week 8. Furthermore, vitamin C supplementation significantly increased self-reported mild, moderate, and strenuous activity levels during the 8-week trial. Overall, total physical activity scores increased nearly 50% in the VTC group as compared to 18% in the CON group (p=0.001). However, mood states were not significantly impacted by vitamin C supplementation during the trial. This study provides the first experimental evidence that supplementing 500 mg of vitamin C twice daily can be effective in increasing leisure-time physical activity in healthy young men. This study, however, was unable to link improvements in physical activity rates to improved mood states. Since sedentary behaviors have been implicated in the rise of obesity in the U.S., further research should be conducted to substantiate the finding that vitamin C supplementation increases physical activity.
ContributorsSchumacher, Sarah (Author) / Johnston, Carol (Thesis advisor) / Appel, Christy (Committee member) / Swan, Pamela (Committee member) / Arizona State University (Publisher)
Created2012
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The antioxidant, antihistamine, and chemotactic properties of vitamin C provide the theoretical basis linking vitamin C supplementation to combating the common cold; yet, the clinical evidence is mixed. To date, vitamin C intervention trials have not systematically recorded cold symptoms daily or looked at fluctuations in plasma histamine over an

The antioxidant, antihistamine, and chemotactic properties of vitamin C provide the theoretical basis linking vitamin C supplementation to combating the common cold; yet, the clinical evidence is mixed. To date, vitamin C intervention trials have not systematically recorded cold symptoms daily or looked at fluctuations in plasma histamine over an extended period. Also, trials have not been conducted in individuals with marginal vitamin C status. This study examined the impact of vitamin C supplementation during cold season on specific cold symptoms in a population with low plasma vitamin C concentrations. Healthy young males who were not regular smokers or training for competitive sports between the ages of 18 and 35 with below average plasma vitamin C concentrations were stratified by age, body mass index, and vitamin C status into two groups: VTC (500 mg vitamin C capsule ingested twice daily) or CON (placebo capsule ingested twice daily). Participants were instructed to fill out the validated Wisconsin Upper Respiratory Symptom Survey-21 daily for 8 weeks. Blood was sampled at trial weeks 0, 4, and 8. Plasma vitamin C concentrations were significantly different by groups at study week 4 and 8. Plasma histamine decreased 4.2% in the VTC group and increased 17.4% in the CON group between study weeks 0 and 8, but these differences were not statistically significant (p>0.05). Total cold symptom scores averaged 43±15 for the VTC group compared to 148±36 for the CON group, a 244% increase in symptoms for CON participants versus VTC participants (p=0.014). Additionally, recorded symptom severity and functional impairment scores were lower in the VCT group than the CON group (p=0.031 and 0.058, respectively). Global perception of sickness was 65% lower in the VTC group compared to the CON group (p=0.022). These results suggest that 1000 mg of vitamin C in a divided dose daily may lower common cold symptoms, cold symptom severity, and the perception of sickness. More research is needed to corroborate these findings.
ContributorsOsterday, Gillean (Author) / Johnston, Carol (Thesis advisor) / Beezhold, Bonnie (Committee member) / Vaughan, Linda (Committee member) / Arizona State University (Publisher)
Created2012
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Birds have unusually high plasma glucose concentrations compared to mammals of similar size despite their high metabolic rate. While birds use lipids as their main source of energy, it is still unclear how and why they maintain high plasma glucose concentrations. To investigate a potential underlying mechanism, this study looks

Birds have unusually high plasma glucose concentrations compared to mammals of similar size despite their high metabolic rate. While birds use lipids as their main source of energy, it is still unclear how and why they maintain high plasma glucose concentrations. To investigate a potential underlying mechanism, this study looks at the role of lipolysis in glucose homeostasis. The purpose of this study is to examine the effects of decreased glycerol availability (through inhibition of lipolysis) on plasma glucose concentrations in mourning doves. The hypothesis is that decreased availability of glycerol will result in decreased production of glucose through gluconeogenesis leading to reduced plasma glucose concentrations. In the morning of each experiment, mourning doves were collected at the Arizona State University Tempe campus, and randomized into either a control group (0.9% saline) or experimental group (acipimox, 50mg/kg BM). Blood samples were collected prior to treatment, and at 1, 2, and 3 hours post-treatment. At 3 hours, doves were euthanized, and tissue samples were collected for analysis. Acipimox treatment resulted in significant increases in blood glucose concentrations at 1 and 2 hours post- treatment as well as renal triglyceride concentrations at 3 hours post-treatment. Change in plasma free glycerol between 0h and 3h followed an increasing trend for the acipimox treated animals, and a decreasing trend in the saline treated animals. These results do not support the hypothesis that inhibition of lipolysis should decrease blood glycerol and blood glucose levels. Rather, the effects of acipimox in glucose homeostasis appear to differ significantly between birds and mammals suggesting differing mechanisms for glucose homeostasis.
ContributorsKouteib, Soukaina (Author) / Sweazea, Karen (Thesis director) / Deviche, Pierre (Committee member) / Chandler, Douglas (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2015-05
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With obesity and metabolic diseases reaching epidemic levels, it is important to find ways to increase physical activity and improve diet. Previous studies have shown that improvements in mood can increase desire to perform physical activity, and that vitamin C intake is linked to improvements in mood. Based on this,

With obesity and metabolic diseases reaching epidemic levels, it is important to find ways to increase physical activity and improve diet. Previous studies have shown that improvements in mood can increase desire to perform physical activity, and that vitamin C intake is linked to improvements in mood. Based on this, two hypotheses were formed and tested to investigate the effect on physical activity levels and mood states from vitamin C supplementation at a dose of one gram per day in the form of a novel functional food. Thirty-one college students or faculty at Arizona State University were screened from a pool of applicants and placed into either a vitamin C or placebo group; all participants received the novel functional food to eat daily for four weeks. Serum levels of vitamin C, weight, height, BMI, body fat percentage, mood, and physical activity were measured before and after the functional food intervention. Vitamin C changed significantly through the course of the study in the experimental group. Baseline data for participants showed a positive correlation between vitamin C status and vigor, and a negative correlation between vitamin C status and weight and BMI. Physical activity was not related to vitamin C status, according to baseline data, and it did not significantly change over the course of the study. The results indicate that variance in BMI can be attributed to vitamin C status, but the study should be refined and tested again.
ContributorsHelland, Stephanie Lynn (Author) / Johnston, Carol (Thesis director) / Sweazea, Karen (Committee member) / Barrett, The Honors College (Contributor) / Department of Chemistry and Biochemistry (Contributor) / Department of Psychology (Contributor) / School of Life Sciences (Contributor) / Graduate College (Contributor)
Created2014-05
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Background Hemodialysis (HD) patients elicit an oxidant-antioxidant imbalance in addition to a selenium deficiency, possibly contributing to cardiovascular disease (CVD) mortality. Objective To evaluate the effect of selenium supplementation on CVD outcomes and antioxidant status in HD patients. Design A randomized controlled intervention trial conducted from October 2012 to January

Background Hemodialysis (HD) patients elicit an oxidant-antioxidant imbalance in addition to a selenium deficiency, possibly contributing to cardiovascular disease (CVD) mortality. Objective To evaluate the effect of selenium supplementation on CVD outcomes and antioxidant status in HD patients. Design A randomized controlled intervention trial conducted from October 2012 to January 2013. Participants/setting The study included 27 maintenance HD patients (61.1+17.5y, 14M, 13F) receiving HD in the greater Phoenix, AZ area. Intervention Patients received one of three treatments daily: 2 Brazil nuts, (5g, 181µg/day of selenium as selenomethionine [predicted]), 1 tablet of selenium (200µg/day of selenium as selenomethionine), or control (3 gummy bears). Main outcome measures Antioxidant status outcome measures included total antioxidant capacity, vitamin C, and RBC and plasma glutathione peroxidase (GSH-Px). CVD outcomes measures included brain natriuretic peptide; plasma cholesterol, high density lipoprotein, low density lipoprotein, triglycerides; blood pressure, and thoracic cavity fluid accumulation. Statistical analyses performed Repeated measures ANOVA analyzed changes over time and between groups at months 0 and 2 and months 0 and 3. Results Independent analysis showed the Brazil nuts provided 11µg of selenium/day and the pill provided 266µg of selenium/day. Consequently, the Brazil nut group was combined with the placebo group. 21 patients completed 2 months of the study and 17 patients completed the study in its entirety. Data was analyzed for months 0, 1 and 2. No significant differences were noted for antioxidant status outcome measures with the exception of plasma GSH-Px. Patients receiving the selenium pill had a significant increase in plasma GSH-Px compared to the placebo group (6.0+11 and -4.0+7.6, respectively, p=0.023 for change between month 0 and month 2). No significant differences were seen in total antioxidant capacity or for CVD outcome measures over time or between groups. Conclusions These data indicate that selenium supplementation increased plasma GSH-Px concentration in HD patients; however, oxidative stress was not altered by selenium supplementation. The low vitamin C status of HD patients warrants further research, specifically in conjunction with selenium supplementation.
ContributorsSussman, Elizabeth Jessica (Author) / Johnston, Carol S (Thesis advisor) / Boren, Kenneth (Committee member) / Mayol-Kreiser, Sandra (Committee member) / Sweazea, Karen (Committee member) / Vaughan, Linda (Committee member) / Arizona State University (Publisher)
Created2013
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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

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