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- All Subjects: Nutrition
- All Subjects: Physiology
- Creators: Swan, Pamela
- Status: Published
Description
Purpose: The purpose of this study was to examine the acute effects of two novel intermittent exercise prescriptions on glucose regulation and ambulatory blood pressure. Methods: Ten subjects (5 men and 5 women, ages 31.5 ± 5.42 yr, height 170.38 ± 9.69 cm and weight 88.59 ± 18.91 kg) participated in this four-treatment crossover trial. All subjects participated in four trials, each taking place over three days. On the evening of the first day, subjects were fitted with a continuous glucose monitor (CGM). On the second day, subjects were fitted with an ambulatory blood pressure monitor (ABP) and underwent one of the following four conditions in a randomized order: 1) 30-min: 30 minutes of continuous exercise at 60 - 70% VO2peak; 2) Mod 2-min: twenty-one 2-min bouts of walking at 3 mph performed once every 20 minutes; 3) HI 2-min: eight 2-min bouts of walking at maximal incline performed once every hour; 4) Control: a no exercise control condition. On the morning of the third day, the CGM and ABP devices were removed. All meals were standardized during the study visits. Linear mixed models were used to compare mean differences in glucose and blood pressure regulation between the four trials. Results: Glucose concentrations were significantly lower following the 30-min (91.1 ± 14.9 mg/dl), Mod 2-min (93.7 ± 19.8 mg/dl) and HI 2-min (96.1 ± 16.4 mg/dl) trials as compared to the Control (101.1 ± 20 mg/dl) (P < 0.001 for all three comparisons). The 30-min trial was superior to the Mod 2-min, which was superior to the HI 2-min trial in lowering blood glucose levels (P < 0.001 and P = 0.003 respectively). Only the 30-min trial was effective in lowering systolic ABP (124 ± 12 mmHg) as compared to the Control trial (127 ± 14 mmHg; P < 0.001) for up to 11 hours post exercise. Conclusion: Performing frequent short (i.e., 2 minutes) bouts of moderate or high intensity exercise may be a viable alternative to traditional continuous exercise in improving glucose regulation. However, 2-min bouts of exercise are not effective in reducing ambulatory blood pressure in healthy adults.
ContributorsBhammar, Dharini Mukeshkumar (Author) / Gaesser, Glenn A (Thesis advisor) / Shaibi, Gabriel (Committee member) / Buman, Matthew (Committee member) / Swan, Pamela (Committee member) / Lee, Chong (Committee member) / Arizona State University (Publisher)
Created2013
Description
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
Description
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
Description
Nut consumption, specifically almonds, have been shown to help maintain weight and influence disease risk factors in adult populations. Limited studies have been conducted examining the effect of a small dose of almonds on energy intake and body weight. The objective of this study was to determine the influence of pre-meal almond consumption on energy intake and weight in overweight and obese adults. In this study included 21, overweight or obese, participants who were considered healthy or had a controlled disease state. This 8-week parallel arm study, participants were randomized to consume an isocaloric amount of almonds, (1 oz) serving, or two (2 oz) cheese stick serving, 30 minutes before the dinner meal, 5 times per week. Anthropometric measurements including weight, waist circumference, and body fat percentage were recorded at baseline, week 1, 4, and 8. Measurement of energy intake was self-reported for two consecutive days at week 1, 4 and 8 using the ASA24 automated dietary program. The energy intake after 8 weeks of almond consumption was not significantly different when compared to the control group (p=0.965). In addition, body weight was not significantly reduced after 8 weeks of the almond intervention (p=0.562). Other parameters measured in this 8-week trial did not differ between the intervention and the control group. These data presented are underpowered and therefore inconclusive on the effects that 1 oz of almonds, in the diet, 5 per week has on energy intake and bodyweight.
ContributorsMcBride, Lindsey (Author) / Johnston, Carol (Thesis advisor) / Swan, Pamela (Committee member) / Mayol-Kreiser, Sandra (Committee member) / Arizona State University (Publisher)
Created2011
Description
The popularization of energy drink use as a supplement to exercise is steadily increasing, especially among young adult males. However, the effects of energy drinks on muscular performance in young adults have yet to be clearly elucidated. Eight male subjects (mean age: 23.3 ± 4.3 yrs, height: 181.0 ± 5.3 cm, fat percent 17.8 ± 5.2%, and weight 85.3 ± 12.6 kg) completed this randomized double-blinded cross over study. The purpose of this study was to determine differences in acute muscular strength and endurance and Profile of Mood States (POMS) scores between three treatments (RockStar, sugar-free RockStar, and sugar-free caffeine-free Placebo). It was hypothesized that there would be no significant differences in acute peak torque and endurance of the knee extensors and flexors or on fatigue and vigor subscores from the POMS questionnaire. Each man was tested randomly at least 1 week apart. Diet and time of day were held constant across trials. Peak torque of knee extensors and flexors at 60, 180, 240 degress/second and fatigue index and total work were calculated by performing 50 repetitions at 240 degrees/second. There were no significant differences in peak torque, fatigue index, or total work measures or in subjective measures of fatigue or vigor from the POMS between the treatments. This study indicates that RockStar energy drinks have no acute ergogenic effects in young men performing isokinetic strength or endurance testing.
ContributorsHawley, Michelle (Author) / Swan, Pamela (Thesis advisor) / Campbell, Kathryn (Committee member) / Johnston, Carol (Committee member) / Arizona State University (Publisher)
Created2012
Description
Most American children consume less than the recommend amount of fruits and vegetables (F&V), 74% and 84%, respectively. Eating too few F&V in childhood is associated with increased risk of cardiovascular disease, hypertension, respiratory symptoms, and some cancers later in life. Adequate F&V consumption favorably impacts antioxidant status, gut flora, mood, and cognitive functioning. Nutrients such as vitamin C and fiber are only naturally occurring in plant foods. For many children, school lunches are an important source of F&V. This pilot study assessed the feasibility of providing condiments to increase children’s consumption of salad bar F&V in an elementary school cafeteria at lunchtime. The trial site was a single Title 1 elementary school in a large, urban district in the greater Phoenix metropolitan area. Taste tests were conducted on three convenience samples of children in grades 3 – 7, aged 8 – 12 years (n=57) to identify the most popular condiment flavors. The five highest rated flavors were made available daily at a “flavor station” in the school’s lunchroom for three consecutive weeks during the Fall 2018 semester. Descriptive and inferential statistics were used to analyze data. A cost analysis was conducted for capital outlays related to the flavor station. School employee perceptions of F&V and the flavor station were assessed via posttest online surveys. Peanut butter was rated the best tasting condiment by children and was the only condiment that increased in popularity throughout the intervention. Overall, daily F&V consumption increased 17 g per child. There was a linear increase in F&V consumption during the study (r=0.986; P=0.014). As a proportion of the total F&V selected, F&V waste decreased by nearly 3%. The average daily cost of providing the flavor station was $0.09 per student. Sixty-five percent of school staff felt that the flavor station should continue at their school. Peanut butter is an affordable, nutrient-dense food that accommodates the USDA Food and Nutrition Service meal patterns and nutrition standards, and thus, is a viable strategy for increasing F&V consumption and decreasing F&V waste. The results herein inform the development of future interventions to improve the palatability of F&V for children.
ContributorsScholtz, Cameron (Author) / Johnston, Carol (Thesis advisor) / Alexon, Christy (Committee member) / Hooker, Steven (Committee member) / Schwake, David (Committee member) / Swan, Pamela (Committee member) / Wharton, Christopher (Christopher Mack), 1977- (Committee member) / Arizona State University (Publisher)
Created2019
Description
PURPOSE: Lean hypertension (HTN) is characterized by a mechanistically different HTN when compared to obese HTN. The purpose of this study is to assess whether body phenotype influences blood pressure (BP) responses following both acute and chronic exercise. METHODS: Obese (body mass index (BMI) > 30 kg/m2) and lean (BMI < 25 kg/m2) men with pre-hypertension (PHTN) (systolic BP (SBP) 120 - 139 or diastolic BP (DBP) 80 - 89 mm Hg) were asked to participate in a two-phase trial. Phase 1 assessed differences in post-exercise hypotension between groups in response to an acute exercise bout. Phase 2 consisted of a two-week aerobic exercise intervention at 65-70% of heart rate (HR) max on a cycle ergometer. Primary outcome measures were: brachial BP, central (aortic) BP, cardiac output (CO), and systemic vascular resistance (SVR) measured acutely after one exercise session and following two weeks of training. RESULTS: There were no differences between groups for baseline resting brachial BP, central BP, age, or VO2 peak (all P > 0.05). At rest, obese PHTN had greater CO compared to lean PHTN (6.3 ± 1 vs 4.7 ± 1 L/min-1, P = 0.005) and decreased SVR compared to lean PHTN (1218 ± 263 vs 1606 ± 444 Dyn.s/cm5, P = 0.003). Average 60-minute post-exercise brachial and central SBP reduced by 3 mm Hg in Lean PHTN in response to acute exercise (P < 0.005), while significantly increasing 4 mm Hg for brachial and 3 mm Hg for central SBP (P < 0.05). SVR had a significantly greater reduction following acute exercise in lean PHTN (-223 Dyn·s/cm5) compared to obese PHTN (-75 Dyn·s/cm5, P < 0.001). In lean subjects chronic training reduced brachial BP by 4 mm Hg and central BP by 3 mm Hg but training had no effect on the BP’s in obese subjects. Resting BP reduction in response to training was accompanied by reductions in SVR within lean (-169 Dyn·s/cm5, P < 0.001), while obese experienced increased SVR following training (47 Dyn·s/cm5, P < 0.001). CONCLUSION: Hemodynamic response to both acute and chronic exercise training differ between obese and lean individuals.
ContributorsZeigler, Zachary (Author) / Swan, Pamela (Thesis advisor) / Gaesser, Glenn (Committee member) / Buman, Matthew (Committee member) / Angadi, Siddhartha (Committee member) / Farouk, Mookadam (Committee member) / Arizona State University (Publisher)
Created2016
Description
Introduction: Weight cycling is defined as happening when an individual intentionally loses weight and then subsequently regaining the weight over time. Weight cycling has been associated with a number of adverse health consequences and is a risk factor for cardiovascular disease. The large majority of behaviorally based weight loss interventions typically result in full weight regain often with additional weight gained over time with each repeated bout of weight cycling. Mindful eating, which is defined as a non-judgmental awareness of meal related factors, has been found to influence negative behaviors related to weight cycling. Purpose: The purpose of this study was to examine the association between mindful eating and weight cycling in middle aged women.
Methods: This study used an observational design to explore the relationships and characterize responses to the Mindfulness Eating Questionnaire (MEQ) in 75 overweight women (BMI > 25) who self-reported a history of weight cycling using a weight cycling index (WCI). The participants were divided into three groups: non-cyclers (NC) less than three cycles of 10 lbs; moderate cyclers (MC) at least three weight cycles of 10lbs; and severe cyclers (SC) at least three weight cycles of at least 20lbs. Results: NC were significantly (p < 0.05) younger and had lower BMI than the MC and SC groups. There were no significant differences in any of the MEQ subscores based on WCI groups. There were no significant relationships between WCI and any of the MEQ subscores. Conclusion: The Mindful Eating Questionnaire (MEQ), was an insufficient discriminatory measure for use in an observational study on a complex behavior such as weight cycling. Further research to understand eating behavior domains, mindful awareness skills, and risk of weight cycling is needed.
Methods: This study used an observational design to explore the relationships and characterize responses to the Mindfulness Eating Questionnaire (MEQ) in 75 overweight women (BMI > 25) who self-reported a history of weight cycling using a weight cycling index (WCI). The participants were divided into three groups: non-cyclers (NC) less than three cycles of 10 lbs; moderate cyclers (MC) at least three weight cycles of 10lbs; and severe cyclers (SC) at least three weight cycles of at least 20lbs. Results: NC were significantly (p < 0.05) younger and had lower BMI than the MC and SC groups. There were no significant differences in any of the MEQ subscores based on WCI groups. There were no significant relationships between WCI and any of the MEQ subscores. Conclusion: The Mindful Eating Questionnaire (MEQ), was an insufficient discriminatory measure for use in an observational study on a complex behavior such as weight cycling. Further research to understand eating behavior domains, mindful awareness skills, and risk of weight cycling is needed.
ContributorsSmith, Jared McDonald (Author) / Swan, Pamela (Thesis advisor) / Sebren, Ann (Committee member) / Chisum, Jack (Committee member) / Arizona State University (Publisher)
Created2016
Description
Currently, there has been limited research on evaluating the social media use and
competency level of registered dietitian
utritionists (RD/N). With health information increasingly sought on social media, it is imperative to understand the social media competency of health professionals. The social media use, reach, and competency level of a nationwide RD/N sample was assessed utilizing an online survey. The sample (n=500) while mostly female (97%) was representative of RD/Ns compared to the nationwide statistics from the Commission on Dietetic Registration. The sample included RD/Ns from forty-six states with California (n=44), New York (n=42), and Texas (n=34) having the largest proportion of respondents. The majority of RD/Ns engage in social media for personal use (92.4%) and 39.2% engage for professional use. One hundred and twenty-five RD/Ns reported 777 ± 1063 (mean ± SD) social media followers. As compared to non-millennial RD/Ns, millennial RD/Ns engaged significantly more in social media for personal and professional use (+10% and +13.5% respectively, p<0.001) and scored significantly higher for social media competency (p<0.001). Additionally, food and nutrition management and consultant/private practice/industry RD/Ns had significantly higher competency scores than clinical RD/Ns (p=0.015 and p=0.046, respectively). RD/Ns who use social media personally and professionally had a significantly higher competency score than RD/Ns who did not (p<0.001). There were significant associations of Facebook, Twitter, total followers and total average followers with the social media competency score (r=0.265, 0.404, 0.338, & 0.320, respectively) in RD/Ns. Specifically, the social media competency score, was found to explain 16% of the variation in the number of Twitter followers and 10% of the variation in the average number of followers by platform. These data suggest an opportunity to increase RD/Ns’ social media reach (i.e. following) by improving competency level.
competency level of registered dietitian
utritionists (RD/N). With health information increasingly sought on social media, it is imperative to understand the social media competency of health professionals. The social media use, reach, and competency level of a nationwide RD/N sample was assessed utilizing an online survey. The sample (n=500) while mostly female (97%) was representative of RD/Ns compared to the nationwide statistics from the Commission on Dietetic Registration. The sample included RD/Ns from forty-six states with California (n=44), New York (n=42), and Texas (n=34) having the largest proportion of respondents. The majority of RD/Ns engage in social media for personal use (92.4%) and 39.2% engage for professional use. One hundred and twenty-five RD/Ns reported 777 ± 1063 (mean ± SD) social media followers. As compared to non-millennial RD/Ns, millennial RD/Ns engaged significantly more in social media for personal and professional use (+10% and +13.5% respectively, p<0.001) and scored significantly higher for social media competency (p<0.001). Additionally, food and nutrition management and consultant/private practice/industry RD/Ns had significantly higher competency scores than clinical RD/Ns (p=0.015 and p=0.046, respectively). RD/Ns who use social media personally and professionally had a significantly higher competency score than RD/Ns who did not (p<0.001). There were significant associations of Facebook, Twitter, total followers and total average followers with the social media competency score (r=0.265, 0.404, 0.338, & 0.320, respectively) in RD/Ns. Specifically, the social media competency score, was found to explain 16% of the variation in the number of Twitter followers and 10% of the variation in the average number of followers by platform. These data suggest an opportunity to increase RD/Ns’ social media reach (i.e. following) by improving competency level.
ContributorsThompson-Felty, Claudia (Author) / Johnston, Carol (Thesis advisor) / Swan, Pamela (Committee member) / Lespron, Christy (Committee member) / Thornton, Leslie-Jean (Committee member) / Lee, Chong (Committee member) / Arizona State University (Publisher)
Created2017
Description
While literature has examined the associations between emotions and overeating, rarely is the relationship between emotions and food choices included. The purpose of this secondary data analysis was to utilize mobile-based ecological momentary assessment (EMA) surveys to determine the associations among negative, positive, apathetic, and mixed emotions and a variety of food choices in college freshmen living in residence halls. A total of 2142 survey responses from 647 college freshmen were included in this analysis (70.3% female, 51.5% non-white). Mixed model logistic regression assessed the cross-sectional association between emotions and food choices adjusting for gender, race/ethnicity, Pell grant status, highest parental education, and the clustering of repeated measures within person and of students within residence hall. There were no significant associations between negative emotions and food choices. Positive emotions were significantly and inversely associated with eating pizza/fast food (OR=0.6; 95% CI=0.5, 0.8) and cereals (OR=0.6; 95% CI=0.4, 1.0), while apathetic emotions were significantly and positively associated with consuming salty snacks/fried foods (OR=1.6; 95% CI=1.1, 2.5) and inversely associated with consuming sandwiches/wraps (OR=0.5; 95% CI=0.3, 0.8) and meats/proteins (OR=0.6; 95% CI=0.4, 1.0). It was also found that there were several instances of surveys with mixed emotions, in which participants reported feeling two conflicting emotions at once (i.e. positive and negative). Mixed emotions were significantly associated with consuming sweets (OR=1.6; 95% CI=1.2, 2.1), meats/proteins (OR=1.6; 95% CI=1.2, 2.0), and cereals (OR=1.9; 95% CI=1.2, 2.9). Understanding the relationships between different types of emotions and food choices is helpful in understanding the motivation behind healthy versus unhealthy food choices. These findings can be used to develop interventions that encourage positive emotions in college freshmen to better promote healthy food choices and ultimately reduce the risk of weight gain and other health disparities. Future research should examine how college freshmen differ from other college students (i.e. upper classmen and graduate students), particularly related to their emotions and food choices, so that dietary interventions can be better suited to those who are vulnerable.
ContributorsAshurst, Jessica (Author) / Bruening, Meg (Thesis advisor) / Ohri-Vachaspati, Punam (Committee member) / Swan, Pamela (Committee member) / Arizona State University (Publisher)
Created2016