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- All Subjects: Nutrition
- Genre: Academic theses
- Genre: Masters Thesis
- Creators: Johnston, Carol S
- Resource Type: Text
Description
Mexican Americans have an increased risk for type 2 diabetes and premature cardiovascular disease (CVD). The association of hyperglycemia with traditional CVD risk factors in this population has been established, but there is limited data regarding other non-traditional CVD risk factors. Thus, this cross-sectional study was conducted to evaluate CVD risk among Mexican Americans by measuring concentrations of lipids, high-sensitivity C-reactive protein (hsCRP), and cholesterol in low-density-lipoprotein (LDL) and high-density-lipoprotein (HDL) subfractions. Eighty overweight/obese Mexican-American adults participating in the Maricopa Insulin Resistance Initiative were randomly selected from each of the following four groups (n = 20 per group): nomolipidemic
ormoglycemic controls (NC), dyslipidemic
ormoglycemic (DN), dyslipidemic/prediabetic (DPD) and dyslipidemic/diabetic (DD). Total cholesterol (TC) was 30% higher among DD than in NC participants (p<0.0001). The DPD group had 27% and 12% higher LDL-C concentrations than the NC and DN groups, respectively. Similarly, LDL-C was 29% and 13% higher in DD than in NC and DN participants (p=0.013). An increasing trend was observed in %10-year CVD risk with increasing degree of hyperglycemia (p<0.0001). The NC group had less cholesterol in sdLDL particles than dyslipidemic groups, regardless of glycemic status (p<0.0001). When hyperglycemia was part of the phenotype (DPD and DD), there was a greater proportion of total and HDL-C in sHDL particles in dyslipidemic individuals than in NC (p=0.023; p<0.0001; respectively). Percent 10-year CVD risk was positively correlated with triglyceride (TG) (r=0.384, p<0.0001), TC (r=0.340, p<0.05), cholesterol in sdLDL(r=0.247; p<0.05), and TC to HDL-C ratio (r=0.404, p<0.0001), and negatively correlated with HDL-C in intermediate and large HDL(r=-0.38, p=0.001; r=0.34, p=0.002, respectively). The TC/HDL-C was positively correlated with cholesterol in sdLDL particles (r=0.698, p<0.0001) and HDL-C in sHDL particles (r=0.602, p<0.0001), and negatively correlated with cholesterol in small (r=-0.35, p=0.002), intermediate (r=-0.91, p<0.0001) and large (r=-0.84, p<0.0001) HDL particles, and HDL-C in the large HDL particles (r=-0.562, p<0.0001). No significant association was found between %10-year CVD risk and hsCRP. Collectively, these results corroborate that dyslipidemic Mexican-American adults have higher CVD risk than normolipidemic individuals. Hyperglycemia may further affect CVD risk by modulating cholesterol in LDL and HDL subfractions.
ormoglycemic controls (NC), dyslipidemic
ormoglycemic (DN), dyslipidemic/prediabetic (DPD) and dyslipidemic/diabetic (DD). Total cholesterol (TC) was 30% higher among DD than in NC participants (p<0.0001). The DPD group had 27% and 12% higher LDL-C concentrations than the NC and DN groups, respectively. Similarly, LDL-C was 29% and 13% higher in DD than in NC and DN participants (p=0.013). An increasing trend was observed in %10-year CVD risk with increasing degree of hyperglycemia (p<0.0001). The NC group had less cholesterol in sdLDL particles than dyslipidemic groups, regardless of glycemic status (p<0.0001). When hyperglycemia was part of the phenotype (DPD and DD), there was a greater proportion of total and HDL-C in sHDL particles in dyslipidemic individuals than in NC (p=0.023; p<0.0001; respectively). Percent 10-year CVD risk was positively correlated with triglyceride (TG) (r=0.384, p<0.0001), TC (r=0.340, p<0.05), cholesterol in sdLDL(r=0.247; p<0.05), and TC to HDL-C ratio (r=0.404, p<0.0001), and negatively correlated with HDL-C in intermediate and large HDL(r=-0.38, p=0.001; r=0.34, p=0.002, respectively). The TC/HDL-C was positively correlated with cholesterol in sdLDL particles (r=0.698, p<0.0001) and HDL-C in sHDL particles (r=0.602, p<0.0001), and negatively correlated with cholesterol in small (r=-0.35, p=0.002), intermediate (r=-0.91, p<0.0001) and large (r=-0.84, p<0.0001) HDL particles, and HDL-C in the large HDL particles (r=-0.562, p<0.0001). No significant association was found between %10-year CVD risk and hsCRP. Collectively, these results corroborate that dyslipidemic Mexican-American adults have higher CVD risk than normolipidemic individuals. Hyperglycemia may further affect CVD risk by modulating cholesterol in LDL and HDL subfractions.
ContributorsNeupane, Srijana (Author) / Vega-Lopez, Sonia (Thesis advisor) / Shaibi, Gabriel Q (Committee member) / Johnston, Carol S (Committee member) / Arizona State University (Publisher)
Created2011
Description
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
Description
In recent years, overall consumption of meat products has been decreasing, and at the same time vegetarianism is on the rise. A variety of factors are likely driving changes in consumers' attitudes towards, and consumption of, meat products. Although concern regarding animal welfare may contribute to these trends, growing consumer interest in the roles that production and processing of meat play in terms of environmental degradation could also impact individuals' decisions about the inclusion of meat in their diets. Because these factors could be related to moral attitudes as well, the purpose of this study was to explore the relations among meat consumption, general environmental attitudes, and moral `foundations' of decision-making, including concern about minimizing `harm' and maximizing `care,' as well as issues of `purity' and `sanctity.' A survey was conducted among current college students using the New Ecological Paradigm scale and the Moral Foundations Questionnaire to assess environmental and moral attitudes. A food frequency questionnaire was used to assess meat consumption. Multiple linear regression analyses explored the relations of environmental and moral attitudes with meat consumption, controlling for potential confounding variables. The results showed no significant correlations among meat consumption, environmental attitudes or moral foundations of harm/care and purity/sanctity.
ContributorsSpringer, LeeAnn (Author) / Wharton, Christopher (Christopher Mack), 1977- (Thesis advisor) / Hekler, Eric (Thesis advisor) / Ohri-Vachaspati, Punam (Committee member) / Hall, Rick (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
ABSTRACT Fruit and vegetable intake is not uniform across levels of socioeconomic status (SES) and researchers have identified low SES as a risk factor for poor intake of fruits and vegetables. In an effort to eliminate public health disparities and increase fruit and vegetable intake, the Women, Infant, and Children (WIC) program implemented additional food assistance programs, with a specific emphasis on fresh fruits and vegetables. The Farmers' Market Nutrition Program (FMNP) provides pre-existing WIC clients with coupons to purchase fresh, locally grown produce at farmers' markets. In addition, Congress also approved the WIC Cash Value Voucher (CVV) program, which provides WIC participants with vouchers to purchase fresh fruits and vegetables at farmers' markets or grocery stores. The purpose of this thesis was to investigate the relation of FMNP coupon use with accessibility and WIC CVV redemption rates at farmers' markets. Furthermore, this thesis addressed whether WIC shoppers redeemed a higher percentage of their WIC CVV value at farmers' markets or grocery stores. WIC CVV and FMNP issuance and redemption data were analyzed to establish overall redemption rates and total perecent of WIC CVV value redeemed. Accessibility was assessed using the Geographic Information System, which allowed me to calculate the distance that WIC participants would have to travel to redeem their FMNP coupons at FMNP-approved farmers' markets. The results showed that less than 1% of WIC shoppers redeem their WIC CVVs at farmers'markets in Arizona. However, the redemption of WIC CVV was significantly higher during the months when shoppers had the option of using both WIC CVV and FMNP coupons at farmers' markets. Furthermore, the percent of total CVV value redeemed at farmers' markets was 99%, significantly higher than grocery stores (93.5%). Average FMNP coupon redemption rates for 2008-2010 was 43.3%, well below the national average of 59%. However, my spatial analysis revealed that there was no significant association between the distance traveled to farmers' markets and FMNP redemption rates. This indicates that the distance traveled to farmers' markets is not a major barrier to redemption of FMNP coupons in Arizona.
ContributorsTucker, Wesley Jack (Author) / Wharton, Christopher (Christopher Mack), 1977- (Thesis advisor) / Vaughan, Linda (Committee member) / Johnston, Carol S (Committee member) / Arizona State University (Publisher)
Created2012
Description
Among its many roles in the body, ascorbic acid functions as a cofactor in carnitine and catecholamine synthesis, metabolites involved in fat oxidation and mood regulation, respectively. Given that fat oxidation and mood affect one's feelings of vigor, I hypothesized that those with lower levels of plasma ascorbic acid would be less likely to exercise at high levels than individuals with adequate or high levels of vitamin C. To test this, I conducted a double-blind, placebo-controlled intervention. A group of healthy, non-smoking males between the ages of 18 and 40 were put on a vitamin C-restricted diet for two weeks and then randomized to a control group that received placebo capsules for six weeks or an intervention group that received 500 mg of vitamin C daily for six weeks. The men were restricted from eating foods high in vitamin C, instructed to wear a pedometer daily and to record their step counts, and to take a pill daily (either the placebo or vitamin C supplement). Unexpectedly, the subjects receiving the intervention had lower step counts than the control group; the control group, rather than the vitamin C group, significantly (p=0.017) increased their steps at week 8 compared to week 2. However, I also estimated daily Metabolic Equivalent Tasks (METs), and subjects receiving the placebo had lower MET outputs than subjects receiving vitamin C at the end of the trial, in spite of having higher step counts. This means the intensity of their activity was higher, based on METs expenditure. Additionally, depression scores (POMS-D) as measured by the Profile of Mood States (POMS) questionnaire were significantly higher (p=0.041) among subjects receiving the placebo at the end of the study. These latter results are consistent with my expectations that subjects with higher levels of plasma vitamin C would have improved mood and higher energy output than subjects with low levels of vitamin C.
ContributorsNetland, Heidi (Author) / Johnston, Carol S (Thesis advisor) / Swan, Pamela D (Committee member) / Hampl, Jeffery S (Committee member) / Arizona State University (Publisher)
Created2011
Description
Chronic low-grade inflammation is a main pathogenic link between obesity and Type 2 Diabetes (T2D) and a putative target for treatment. While a wide array of pharmacologic agents is available to manage T2D, many patients still face perturbed glycemia and subclinical inflammation. Therefore, complementary nutraceutical strategies that target inflammation, metabolism, and resolution physiology hold promise as adjunctive options to quell the disturbed immuno-metabolic milieu observed in T2D. Omega-3 polyunsaturated fatty acids (PUFAs) and anthocyanins are two dietary components evidenced to mitigate inflammation and improve T2D risk factors, through distinct and similar targets. However, the combined use of such nutraceuticals has not yet been examined in individuals with T2D. This dissertation leveraged data from a larger randomized, double-blind, placebo-controlled trial conducted between January 2022—September 2023 investigating the use of combined supplementation (active treatment; [FOM]) of anthocyanins (600 mg/d maqui berry extract) and omega-3 PUFAs (3 g/day fish oil; 2 g/d EPA, 1 g/d DHA) for 8 weeks on cytokines and mental acuity in individuals with T2D, compared to a placebo (CON). The current study examined the effects of this supplemental strategy on markers of metabolic inflammation, oxidative stress, and cardiometabolic risk. The results indicated that a marker of sustained omega-3 dietary intake and tissue accumulation termed the Omega-3 Index was inversely associated with HbA1c (? = -8.5, 95%CI -15.1, -1.4, p = 0.022) and glucose (? = -12.4, 95%CI -22.9, -0.5, p = 0.042), after adjustment for covariates at baseline across all participants with T2D in this study. However, outcomes from linear mixed model analyses demonstrated that there were no significant differences in change from baseline between FOM and CON groups at week 8 in any of the inflammatory, oxidative stress, glycemic control, or circulating lipid markers assessed in this study. These null effects were observed despite a 93% greater increase from baseline in the Omega-3 Index observed in the FOM group compared to the CON group at week 8. Therefore, the findings do not support significant treatment effects associated with 2 months of combined marine omega-3 PUFAs and maqui berry extract on inflammatory and cardiometabolic outcomes in individuals with T2D.
ContributorsFessler, Samantha Nicole (Author) / Johnston, Carol S (Thesis advisor) / Sweazea, Karen (Committee member) / Wang, Shu (Committee member) / Kavouras, Stavros A (Committee member) / Grimm, Kevin J (Committee member) / Arizona State University (Publisher)
Created2024
Description
Obesity prevalence is high in the United States, in part due to increased fat storage following consumption of high fat/carbohydrate (sugar) foods. Following a meal, carbohydrate stimulates its own oxidation, while simultaneously suppressing fat oxidation, ultimately leading to fat storage. Aerobic exercise preceding a meal increases fat oxidation in the postprandial period, which may reduce fat storage. The ideal exercise prescription for optimal postprandial fat oxidation is unknown. The effect of low and moderate intensity continuous exercise (MIE) has been studied extensively, while the effects of high-intensity interval exercise (HIIE) on post-prandial substrate oxidation has not been examined. The purpose of this study was to compare the effects of MIE and HIIE on postprandial substrate oxidation after consumption of an isocaloric meal (2 glazed donuts; 520 kcal) in healthy adults. Ten subjects (8 males, 2 females; age=24yr, BMI=24 kg/m2) completed three conditions in random order: 1) no exercise control; 2) MIE: cycling at 60-75%HRmax; 3) HIIE: cycling at 90-95%HRmax. The duration of each exercise bout was sufficient to expend approximately 520 kcal, the energy equivalent of the donuts, which were consumed 1 hour post-exercise. Immediately after consuming the donuts, pulmonary ventilation and gas exchange were measured breath-by-breath continuously and recorded (min-by-min) for 5 hours. Repeated measures analysis of covariance was used to compare the mean differences in outcome variables accounting for gender. Absolute postprandial fat oxidation (g/5 hours) was 17.3±5.4, 27.1±9.6 and 23±1.2 for control, MIE and HIIE trials respectively, with the postprandial fat oxidation significantly greater for the two exercise conditions compared to control. Relative to baseline values, both exercise conditions resulted in cumulative net postprandial fat oxidation significantly greater than control (control = -1.79±3.99g; MIE = 11.51±8.41g, HIIE= 9.51±5.20g). Therefore, results indicate that exercise most certainly increases postprandial fat oxidation, and that exercise type, either MIE or HIIE, is not as important as total energy expended. The fact that exercise of ~1 hour was required to oxidize the amount of fat in two donuts, that required only a few minutes to consume, highlights the challenges of using exercise for weight control in an obesogenic environment.
ContributorsFleming, Jacob Michael (Author) / Johnston, Carol S (Thesis advisor) / Gaesser, Glenn A (Committee member) / Grant, Shauna (Committee member) / Arizona State University (Publisher)
Created2018
Description
According to a 2016 census, eight million adults conform to a vegetarian diet within the United States, and about 50% of these adults follow a vegan diet. The census determined that plant-based diets are quickly growing in popularity particularly in young adults between the ages of 18 to 34 years. Many Americans are aware of the health benefits of a plant-based diet, however, the dietary risks associated with these diets are not well emphasized. Health concerns such as vitamin deficiencies and altered metabolism are heightened in vegetarian populations.
One Particular nutrient that is commonly lacking in the vegetarian diet is vitamin B12. Vitamin B12 is found mainly in animal-derived food sources such as meat, poultry, fish, dairy, and eggs. Although some vegetarians, called lacto-ovo vegetarians, consume dairy and eggs, vegans do not consume any animal products at all. Vitamin B12 deficiency can have devastating consequences on the human body due to its role as a methylation cofactor. Metabolism, DNA replication, and cancer formation all involve methylation processes.
This cross-sectional, differential study aimed to further understand the relationship between vegetarianism, vitamin B12 status, and methylation capacity in healthy adults. A group of 34 healthy adults (18 vegetarians and 16 omnivores) was recruited to analyze serum B12, homocysteine, methylmalonic acid, serum total folate, and transcobalamin II status. It was hypothesized that (1) vegetarians would have a lower vitamin B12 status, and thus, a lower methylation capacity than omnivores and that (2) low vitamin B12 status would be correlated with low methylation capacity.
The data show that vegetarians did not have significantly lower vitamin B12 methylation capacity status than omnivores. Nor was vitamin B12 status correlated with methylation capacity. However, the data revealed that diet quality had a positive influence on folate status. There was also a statistical trend (p=0.08) for homocysteine reduction in participants consuming high-quality diets. The data herein suggest that methylation capacity may be impacted by the quality of diet rather than the type of diet.
One Particular nutrient that is commonly lacking in the vegetarian diet is vitamin B12. Vitamin B12 is found mainly in animal-derived food sources such as meat, poultry, fish, dairy, and eggs. Although some vegetarians, called lacto-ovo vegetarians, consume dairy and eggs, vegans do not consume any animal products at all. Vitamin B12 deficiency can have devastating consequences on the human body due to its role as a methylation cofactor. Metabolism, DNA replication, and cancer formation all involve methylation processes.
This cross-sectional, differential study aimed to further understand the relationship between vegetarianism, vitamin B12 status, and methylation capacity in healthy adults. A group of 34 healthy adults (18 vegetarians and 16 omnivores) was recruited to analyze serum B12, homocysteine, methylmalonic acid, serum total folate, and transcobalamin II status. It was hypothesized that (1) vegetarians would have a lower vitamin B12 status, and thus, a lower methylation capacity than omnivores and that (2) low vitamin B12 status would be correlated with low methylation capacity.
The data show that vegetarians did not have significantly lower vitamin B12 methylation capacity status than omnivores. Nor was vitamin B12 status correlated with methylation capacity. However, the data revealed that diet quality had a positive influence on folate status. There was also a statistical trend (p=0.08) for homocysteine reduction in participants consuming high-quality diets. The data herein suggest that methylation capacity may be impacted by the quality of diet rather than the type of diet.
ContributorsUgarte, Noel (Author) / Johnston, Carol S (Thesis advisor) / Whisner, Corrie (Committee member) / Sweazea, Karen (Committee member) / Arizona State University (Publisher)
Created2019
Description
The stadiometer is the gold standard human height measure, but recent studies have begun to question whether laser technology is a better tool to measure height. The purpose of this study was to investigate if the laser device has inter-rater reliability, how the laser-device measures supine height in comparison to standard methods, and if the laser device will be consistent in measuring human height shorter, as seen in previous studies. Two investigators measured a total of 80 adults independently. Measurements included knee height, arm span, demi span, supine height by laser, standing height by laser and standing height by stadiometer. There was a strong inter-rater reliability for the laser height measurement: excluding one outlier r=0.998. Supine height measures done with a laser were strongly correlated with arm span, but mean values were closest between supine height and knee height (171.3cm and 171.2cm). The laser measured standing height 0.5cm shorter, on average, than the stadiometer. It is concluded that the laser device is a reliable, validated tool to measure human height, standing or supine.
ContributorsGarcia-Turner, Vanessa (Author) / Johnston, Carol S (Thesis advisor) / Mayol-Kreiser, Sandra N (Committee member) / Bruening, Meg (Committee member) / Arizona State University (Publisher)
Created2016