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- All Subjects: Nutrition
- Creators: Levinson, Simin
- Creators: Dixon, Kathleen
Description
Objective: Vinegar consumption studies have demonstrated possible therapeutic effects in reducing HbA1c and postprandial glycemia. The purpose of the study was to closely examine the effects of a commercial vinegar drink on daily fluctuations in fasting glucose concentrations and postprandial glycemia, and on HbA1c, in individuals at risk for Type 2 Diabetes Mellitus (T2D). Design: Thirteen women and one man (21-62 y; mean, 46.0±3.9 y) participated in this 12-week parallel-arm trial. Participants were recruited from a campus community and were healthy and not diabetic by self-report. Participants were not prescribed oral hypoglycemic medications or insulin; other medications were allowed if use was stable for > 3 months. Subjects were randomized to one of two groups: VIN (8 ounces vinegar drink providing 1.5 g acetic acid) or CON (1 vinegar pill providing 0.04 g acetic acid). Treatments were taken twice daily immediately prior to the lunch and dinner meals. Venous blood samples were drawn at trial weeks 0 and 12 to measure insulin, fasting glucose, and HbA1c. Subjects recorded fasting glucose and 2-h postprandial glycemia concentrations daily using a glucometer. Results: The VIN group showed significant reductions in fasting capillary blood glucose concentrations (p=0.05) that were immediate and sustained throughout the duration of the study. The VIN group had reductions in 2-h postprandial glucose (mean change of −7.6±6.8 mg/dL over the 12-week trial), but this value was not significantly different than that for the CON group (mean change of 3.3±5.3 mg/dL over the 12-week trial, p=0.232). HbA1c did not significantly change (p=0.702), but the reduction in HbA1c in the VIN group, −0.14±0.1%, may have physiological relevance. Conclusions: Significant reductions in HbA1c were not observed after daily consumption of a vinegar drink containing 1.5 g acetic acid in non-diabetic individuals. However, the vinegar drink did significantly reduce fasting capillary blood glucose concentrations in these individuals as compared to a vinegar pill containing 0.04 g acetic acid. These results support a therapeutic effect for vinegar in T2D prevention and progression, specifically in high-risk populations.
ContributorsQuagliano, Samantha (Author) / Johnston, Carol (Thesis advisor) / Appel, Christy (Committee member) / Dixon, Kathleen (Committee member) / Arizona State University (Publisher)
Created2013
Description
Diet quality is closely intertwined with overall health status and deserves close examination. Healthcare providers are stretched thin in the current stressed system and would benefit from a validated tool for rapid assessment of diet quality. The Rapid Eating and Activity Assessment for Participants Short Version (REAP-S) represents one such option. The objective of the current study was to evaluate the effectiveness of the REAP-S and Healthy Eating Index 2010 (HEI-2010) for scoring the diet quality of omnivorous, vegetarian and vegan diets. Eighty-one healthy male and female subjects with an average age of 30.9 years completed the REAP-S as well as a 24-hour dietary recall. REAP-S and HEI-2010 scores were calculated for each subject and evaluated against each other using Spearman correlations and Chi Square. Further analysis was completed to compare diet quality scores of the HEI-2010 and REAP-S by tertiles to examine how closely these two tools score diet quality. The mean HEI-2010 score was 47.4/100 and the mean REAP-S score was 33.5/39. The correlation coefficient comparing the REAP-S to the HEI-2010 was 0.309 (p=0.005), and the REAP-S exhibited a precision of 44.4% to the HEI-2010 for diet quality. The REAP-S significantly correlated with the HEI-2010 for whole fruit (r=0.247, p=0.026), greens and beans (r=0.276, p=0.013), seafood proteins (r=0.298, p=0.007), and fatty acids (r=0.400, p<0.001). When evaluated by diet type, the REAP-S proved to have increased precision in plant-based diets, 50% for vegetarian and 52% for vegan, over omnivorous diets (32%). The REAP-S is a desirable tool to rapidly assess diet quality in the community setting as it is significantly correlated to the HEI-2010 and requires less time, labor and money to score and assess than the HEI-2010. More studies are needed to evaluate the precision and validity of REAP-S in a broader, more diverse population.
ContributorsBliss, Courtney (Author) / Johnston, Carol (Thesis advisor) / Tasevska, Natasha (Committee member) / Levinson, Simin (Committee member) / Arizona State University (Publisher)
Created2015
Description
There are multivariate factors that not only play a role in an individual's ability to lose weight, but may create barriers to his or her success. One such factor is internalized weight bias (IWB), which is inversely associated with weight loss outcomes and body satisfaction, and directly associated with psychosocial maladjustments such as depression and binge eating. This study examined the relationship between internalized weight bias and weight loss outcomes using a coding scheme developed for an online weight loss forum to see whether results would be consistent with self-administered surveys that measure IWB. The coding scheme was developed using an exploratory factor analysis of a survey composed of existing measures of IWB. Participants' posts within an online weight loss forum were coded and participants given a weekly IWB score that was compared to weekly weight loss using mixed model analysis. No significance was found between IWB and weight loss outcomes in this study, however, the coding scheme developed is a novel approach to measuring IWB, and the categories identified from latent constructs of IWB may be used in the future to determine the dimensions that exist within it. Ultimately, a better understanding of IWB could lead to the development of targeted weight loss interventions that address the beliefs and attitudes held by individuals who experience it.
ContributorsEscajeda, Janessa (Author) / Hekler, Eric (Thesis advisor) / Barroso, Cristina (Thesis advisor) / Dixon, Kathleen (Committee member) / Arizona State University (Publisher)
Created2015
Description
Dietary counseling from a registered dietitian has been shown in previous studies to aid in weight loss for those receiving counseling. With the increasing use of smartphone diet/weight loss applications (app), this study sought to investigate if an iPhone diet app providing feedback from a registered dietitian improved weight loss and bio-markers of health. Twenty-four healthy adults who owned iPhones (BMI > 24 kg/m2) completed this trial. Participants were randomly assigned to one of three app groups: the MyDietitian app with daily feedback from a registered dietitian (n=7), the MyDietitian app without feedback (n=7), and the MyPlate feedback control app (n=10). Participants used their respective diet apps daily for 8-weeks while their weight loss, adherence to self-monitoring, blood bio-markers of health, and physical activity were monitored. All of the groups had a significant reduction in waist and hip circumference (p<0.001), a reduction in A1c (p=0.002), an increase in HDL cholesterol levels (p=0.012), and a reduction in calories consumed (p=0.022) over the duration of the trial. Adherence to diet monitoring via the apps did not differ between groups during the study. Body weight did not change during the study for any groups. However, when the participants were divided into low (<50% of days) or high adherence (>50% of days) groups, irrespective of study group, the high adherence group had a significant reduction in weight when compared to the low adherence group (p=0.046). These data suggest that diet apps may be useful tools for self-monitoring and even weight loss, but that the value appears to be the self-monitoring process and not the app specifically.
ContributorsThompson-Felty, Claudia (Author) / Johnston, Carol (Thesis advisor) / Wharton, Christopher (Christopher Mack), 1977- (Committee member) / Levinson, Simin (Committee member) / Arizona State University (Publisher)
Created2014
Description
This study examined the effect of consuming pinto, black, and dark red kidney beans with white rice in comparison to a white rice only control meal on the glycemic response of adults with type 2 diabetes (T2D). These bean and rice combinations are part of many traditional diets. Seventeen subjects with T2D treated by diet and/or metformin were randomly assigned to 4 treatments: white rice (control), pinto beans/rice, black beans/rice, and dark red kidney beans/rice. All treatments were portioned by weight and matched for available carbohydrate content of ∼ 50 grams. Capillary whole blood samples were collected at baseline and at 30, 60, 90, 120, 150 and 180 minutes posttreatment and assessed for glucose concentration using the YSI Stat Plus Analyzer. Net change glucose responses were significantly lower for the pinto, black, and dark red kidney bean and rice meals than control at 90, 120 and 150 minutes posttreatment (P < 0.05). Incremental area under the curve (iAUC) values were also significantly reduced for the bean/rice meals containing pinto (P < 0.01) and black beans (P < 0.05) in contrast to the rice control. Results suggest that the combination of whole beans and rice may be beneficial to those with T2D to assist with blood glucose management.
ContributorsThompson, Sharon (Author) / Winham, Donna M (Thesis advisor) / Beezhold, Bonnie (Committee member) / Dixon, Kathleen (Committee member) / Arizona State University (Publisher)
Created2011
Description
Water makes up about 45-70% of a human body's total weight. It is estimated that 80% of the human brain's tissue is composed of water. Cognitive productivity is altered when the body is in a mere 2% dehydrated state. Several cognitive functions impacted by dehydration include: visual motor tracing, short-term recall, attentiveness, and mathematic efficiency. It is estimated that 80% of the U.S. adult population endures the majority of their day in a mildly dehydrated state.
Participants were employees working full-time jobs with Arizona State University or Tri Star Motor Company. Employees had to be 18 or older were invited to join the study. Employees participating in the study lived within the the greater Phoenix area. Participants of all races, genders, activity statuses, and BMIs were encouraged to join.
A one-arm, pre-test, post-test study design was utilized. We examined whether the hydration status of participants in the intervention improved or worsened during the course of the intervention, and then attributed any such improvement or deterioration to the intervention. Urine collections from an afternoon sample were gathered before and after the one-week intervention. For the intervention, the participating offices received a water dispensing system in close proximity to employee desk spaces. A reusable water bottle was also given to each participant. Urine specific gravity (USG) was assessed in all urine samples to indicate hydration status, and all participants completed water intake surveys before and after the intervention.
From this study, the overall change in water intake over the course of the one-week intervention was 143 ounces/day. This is an average of adding two and a half 8 oz glasses of water each day of the week per participant. USG also decreased significantly at the end of the intervention in comparison to the baseline value. In the greater body of research, this study strengthens the viability of inputting a hydration station and offering reusable water bottles to employees. This cost-effective method is an easy way to incorporate employee wellness in the workplace. The benefit of employees to drink more water is numerous, including increased focus, mental reactivity, and overall mood and wellness.
Participants were employees working full-time jobs with Arizona State University or Tri Star Motor Company. Employees had to be 18 or older were invited to join the study. Employees participating in the study lived within the the greater Phoenix area. Participants of all races, genders, activity statuses, and BMIs were encouraged to join.
A one-arm, pre-test, post-test study design was utilized. We examined whether the hydration status of participants in the intervention improved or worsened during the course of the intervention, and then attributed any such improvement or deterioration to the intervention. Urine collections from an afternoon sample were gathered before and after the one-week intervention. For the intervention, the participating offices received a water dispensing system in close proximity to employee desk spaces. A reusable water bottle was also given to each participant. Urine specific gravity (USG) was assessed in all urine samples to indicate hydration status, and all participants completed water intake surveys before and after the intervention.
From this study, the overall change in water intake over the course of the one-week intervention was 143 ounces/day. This is an average of adding two and a half 8 oz glasses of water each day of the week per participant. USG also decreased significantly at the end of the intervention in comparison to the baseline value. In the greater body of research, this study strengthens the viability of inputting a hydration station and offering reusable water bottles to employees. This cost-effective method is an easy way to incorporate employee wellness in the workplace. The benefit of employees to drink more water is numerous, including increased focus, mental reactivity, and overall mood and wellness.
ContributorsWildermuth, Kelsi (Author) / Johnston, Carol (Thesis advisor) / Dixon, Kathleen (Committee member) / Levinson, Simin (Committee member) / Arizona State University (Publisher)
Created2018
Description
Vegetarian diets can provide an abundance of nutrients when planned with care. However, research suggests that vegetarian diets may have lower protein quality than omnivore diets. Current protein recommendations assume that vegetarians obtain a majority of their protein from animal products, like dairy and eggs. Studies have shown that this assumption may not be valid. The recommended dietary allowance (RDA) may not be adequate in vegetarian populations with high protein requirements. The purpose of this study is to analyze dietary protein quality using the DIAAS (Digestible Indispensable Amino Acid Score) method in both vegetarian and omnivore endurance athletes. 38 omnivores and 22 vegetarians submitted 7-day food records which were assessed using nutrition analysis software (Food Processor, ESHA Research, Salem, OR, USA). Dietary intake data was used to calculate DIAAS and determine the amount of available dietary protein in subject diets. Dietary data was compared with the subjects’ lean body mass (obtained using DEXA scan technology), and strength (quantified using peak torque of leg extension and flexion using an isokinetic dynamometer). Statistical analyses revealed significantly higher available protein intake in the omnivore athletes (p<.001). There were significant correlations between available protein intake and strength (p=.016) and available protein intake and lean body mass (p<.001). Omnivore subjects had higher lean body mass than vegetarian subjects (p=.011). These results suggest that vegetarian athletes may benefit from higher overall protein intakes to make up for lower dietary protein quality.
ContributorsZuelke, Corinne (Author) / Johnston, Carol (Thesis advisor) / Wharton, Christopher (Christopher Mack), 1977- (Committee member) / Dixon, Kathleen (Committee member) / Arizona State University (Publisher)
Created2017
Description
ABSTRACT
Many natural interventions have been effective at lowering postprandial glucose concentrations (PPG) in research trials and, theoretically, should have favorable effects on the prevention and management of T2DM. Natural interventions include vinegar, nuts and exercise. Green tea has been demonstrated to also possessing antiglycemic effects. Thus, green tea, and its most abundant catechin EGCG, are being consumed for its potential health benefits in cancer prevention and in its inhibitory effects on α-amylase. Many studies have found EGCG to inhibit α-amylase an enzyme needed in the breakdown of carbohydrates (CHO). Other studies have looked at EGCG and its potential for lowering PPG concentrations due to its inhibitory effects on α-amylase in both mice and humans. Yet there is no research on Matcha tea specifically. Matcha tea is green tea in powder form; hence, it is consumed in its entirety unlike traditional teas which are steeped in bags. The purpose of this study was to determine whether Macha tea impacts PPG concentrations in healthy adults. Twelve subjects completed this randomized controlled, single blinded, crossover study. On three separate occasions the twelve subjects consumed a bagel and jam with either water, Lipton green tea, or Macha tea. Fasting blood glucose was taken upon their arrival. Once the tea or water and bagel with jam were consumed PPG concentrations were measured every 30 minutes until 120 minutes were reached. Results showed no statistically significant effects on PPG concentrations in either test groups (p=.960). However, this study did not measure EGCG levels in the tea provided. Therefore, further research should be done with known EGCG amounts to see its effects on PPG concentrations to fully rule out its potential.
Many natural interventions have been effective at lowering postprandial glucose concentrations (PPG) in research trials and, theoretically, should have favorable effects on the prevention and management of T2DM. Natural interventions include vinegar, nuts and exercise. Green tea has been demonstrated to also possessing antiglycemic effects. Thus, green tea, and its most abundant catechin EGCG, are being consumed for its potential health benefits in cancer prevention and in its inhibitory effects on α-amylase. Many studies have found EGCG to inhibit α-amylase an enzyme needed in the breakdown of carbohydrates (CHO). Other studies have looked at EGCG and its potential for lowering PPG concentrations due to its inhibitory effects on α-amylase in both mice and humans. Yet there is no research on Matcha tea specifically. Matcha tea is green tea in powder form; hence, it is consumed in its entirety unlike traditional teas which are steeped in bags. The purpose of this study was to determine whether Macha tea impacts PPG concentrations in healthy adults. Twelve subjects completed this randomized controlled, single blinded, crossover study. On three separate occasions the twelve subjects consumed a bagel and jam with either water, Lipton green tea, or Macha tea. Fasting blood glucose was taken upon their arrival. Once the tea or water and bagel with jam were consumed PPG concentrations were measured every 30 minutes until 120 minutes were reached. Results showed no statistically significant effects on PPG concentrations in either test groups (p=.960). However, this study did not measure EGCG levels in the tea provided. Therefore, further research should be done with known EGCG amounts to see its effects on PPG concentrations to fully rule out its potential.
ContributorsRomash, Roni (Author) / Johnston, Carol (Thesis advisor) / Dixon, Kathleen (Committee member) / Lespron, Christy (Committee member) / Arizona State University (Publisher)
Created2018
Description
Background: The Academy of Nutrition and Dietetics states that it is possible for a vegetarian to obtain the recommended amount of nutrients with a properly planned diet but nutrient deficiencies, such as vitamin B12 deficiency, may occur if diet planning is not optimal. An early indicator of B12 deficiency is raised homocysteine concentrations in blood which can cause health issues.
Objective: The amino acid methionine is consumed via dietary protein. Methionine is used in the biosynthesis of other proteins. After a removal of a methyl group, it makes homocysteine. Slightly raised homocysteine may promote greater synthesis of glutathione, an important endogenous antioxidant protectant. It can then be recycled back into methionine or converted into cysteine with the addition of various B-vitamins such as vitamin B12, folic acid, and vitamin B6. Cysteine then uses outside sources of glutamate and glycine to create glutathione (GSH). With the catalyst glutathione peroxidase it donates an electron and becomes the oxidized form, glutathione disulfide (GSSG). It can then convert back to GSH with the aid of glutathione reductase by using the reduced form of nicotinamide adenine dinucleotide phosphate (NADPH) as an electron donor. This study will examine glutathione levels in omnivores and vegetarians and see if it is related to vitamin B12 and homocysteine levels.
Design: This cross-sectional study encompassed 16 omnivores and 17 vegetarians from Phoenix, Arizona. A vegetarian diet was defined as one that excludes red meat, poultry, pork and seafood but allows dairy products and/or eggs; the diet had to be followed for at least one year. An omnivore diet is defined as eats meat daily. Participants completed a diet questionnaire and a vitamin B12, B6 and folate food questionnaire and provided a fasting blood sample.
Results: The mean plasma B12 and homocysteine did not differ between diet groups. Glutathione was significantly lower among vegetarians in comparison to omnivores, 1.9±0.5 and 2.3±0.7 mmol respectively (p=0.046).
Conclusions: The hypothesis was shown to be incorrect that vegetarians would have a higher glutathione level than omnivores as a result of their modest consumption of vitamin B12. The implications of a reduced glutathione status are discussed.
Objective: The amino acid methionine is consumed via dietary protein. Methionine is used in the biosynthesis of other proteins. After a removal of a methyl group, it makes homocysteine. Slightly raised homocysteine may promote greater synthesis of glutathione, an important endogenous antioxidant protectant. It can then be recycled back into methionine or converted into cysteine with the addition of various B-vitamins such as vitamin B12, folic acid, and vitamin B6. Cysteine then uses outside sources of glutamate and glycine to create glutathione (GSH). With the catalyst glutathione peroxidase it donates an electron and becomes the oxidized form, glutathione disulfide (GSSG). It can then convert back to GSH with the aid of glutathione reductase by using the reduced form of nicotinamide adenine dinucleotide phosphate (NADPH) as an electron donor. This study will examine glutathione levels in omnivores and vegetarians and see if it is related to vitamin B12 and homocysteine levels.
Design: This cross-sectional study encompassed 16 omnivores and 17 vegetarians from Phoenix, Arizona. A vegetarian diet was defined as one that excludes red meat, poultry, pork and seafood but allows dairy products and/or eggs; the diet had to be followed for at least one year. An omnivore diet is defined as eats meat daily. Participants completed a diet questionnaire and a vitamin B12, B6 and folate food questionnaire and provided a fasting blood sample.
Results: The mean plasma B12 and homocysteine did not differ between diet groups. Glutathione was significantly lower among vegetarians in comparison to omnivores, 1.9±0.5 and 2.3±0.7 mmol respectively (p=0.046).
Conclusions: The hypothesis was shown to be incorrect that vegetarians would have a higher glutathione level than omnivores as a result of their modest consumption of vitamin B12. The implications of a reduced glutathione status are discussed.
ContributorsManley, Rachel Christine (Author) / Johnston, Carol (Thesis advisor) / Levinson, Simin (Committee member) / Barth, Christina (Committee member) / Arizona State University (Publisher)
Created2019
Description
University students currently lack sufficient knowledge and resources needed to support healthy eating patterns and nutrition. Comparison of the number of registered dietitians that are available to all students, along with the number of wellness events that are held at each university within the Pacific-12 conference will help determine which schools are best able to support their students' needs. Data was collected using a Google forms survey sent via email to wellness directors of each of the universities in the Pac-12 conference. Eight out of the twelve schools in the conference responded to the survey. The average number of dietitians available to all students (regardless of athlete status) was found to be 1.43 dietitians. Of the schools that responded, the University of Colorado, Boulder, has the most resources dedicated to student nutrition wellness with three dietitians available for all undergraduate students, free dietitian services, and approximately 150 wellness events each year. The success of available nutrition wellness resources was inconclusive as schools did not provide the information regarding student utilization and attendance. Future university promoted nutrition wellness programs should increase the number of affordable dietitians and total wellness events, as well as promote student health services through social media platforms to improve student nutrition knowledge and usage of resources.
ContributorsCurtin, Anne Clare (Author) / Dixon, Kathleen (Thesis director) / McCoy, Maureen (Committee member) / School of Nutrition and Health Promotion (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05