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Dietary protein is known to increase postprandial thermogenesis more so than carbohydrates or fats, probably related to the fact that amino acids have no immediate form of storage in the body and can become toxic if not readily incorporated into body tissues or excreted. It is also well documented that

Dietary protein is known to increase postprandial thermogenesis more so than carbohydrates or fats, probably related to the fact that amino acids have no immediate form of storage in the body and can become toxic if not readily incorporated into body tissues or excreted. It is also well documented that subjects report greater satiety on high- versus low-protein diets and that subject compliance tends to be greater on high-protein diets, thus contributing to their popularity. What is not as well known is how a high-protein diet affects resting metabolic rate over time, and what is even less well known is if resting metabolic rate changes significantly when a person consuming an omnivorous diet suddenly adopts a vegetarian one. This pilot study sought to determine whether subjects adopting a vegetarian diet would report decreased satiety or demonstrate a decreased metabolic rate due to a change in protein intake and possible increase in carbohydrates. Further, this study sought to validate a new device called the SenseWear Armband (SWA) to determine if it might be sensitive enough to detect subtle changes in metabolic rate related to diet. Subjects were tested twice on all variables, at baseline and post-test. Independent and related samples tests revealed no significant differences between or within groups for any variable at any time point in the study. The SWA had a strong positive correlation to the Oxycon Mobile metabolic cart but due to a lack of change in metabolic rate, its sensitivity was undetermined. These data do not support the theory that adopting a vegetarian diet results in a long-term change in metabolic rate.
ContributorsMoore, Amy (Author) / Johnston, Carol (Thesis advisor) / Appel, Christy (Thesis advisor) / Gaesser, Glenn (Committee member) / Arizona State University (Publisher)
Created2012
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Description
In 2002, a scientifically derived food guide pyramid for vegetarians, the Modified Food Guide for Lacto-ovo-vegetarians and Vegans was published and well received. Now that 10 years have passed, new scientific literature regarding the bioavailability of the nutrients of key concern in vegetarian diets has been published, and the graphical

In 2002, a scientifically derived food guide pyramid for vegetarians, the Modified Food Guide for Lacto-ovo-vegetarians and Vegans was published and well received. Now that 10 years have passed, new scientific literature regarding the bioavailability of the nutrients of key concern in vegetarian diets has been published, and the graphical format of the nation's food guide has evolved from a pyramid shape into a circular plate. The objective of this research was to examine the post-2002 literature regarding the bioavailability of key nutrients in vegetarian diets; to use this information to update the recommendations made in the 2002 Modified Food Guide Pyramid for Lacto-ovo-vegetarians and Vegans; and to adapt this revised food plan to the new USDA MyPlate format. This process involved reviewing the scientific literature to determine if the DRIs for the nutrients of key concern in vegetarian diets are adequate for the vegetarian population and using this information to develop new recommendations for vegetarians if necessary, analyzing the nutrient content of representative foods in different food groups, reconfiguring the food groups so that foods with like nutrient components were grouped together, determining the number of servings of each food group required to meet vegetarians' nutrient requirements at three caloric levels, and developing sample menus. A circular plate graphic, the Vegetarian Plate, was designed to illustrate the recommendations of this updated food guide. This updated, scientifically derived food guide provides a sound base for diet planning for lacto-ovo-vegetarians and vegans. Further research is needed to assess the Vegetarian Plate's adequacy for children, pregnant and lactating women, athletes, and individuals with medical conditions or chronic diseases.
ContributorsFladell, Lauren (Author) / Johnston, Carol (Thesis advisor) / Vaughan, Linda (Committee member) / Shepard, Christina (Committee member) / Arizona State University (Publisher)
Created2013
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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

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
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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

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
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Description
Background: Vegan and vegetarian diets have gained in popularity in recent years. Stated reasons for this include some possible health benefits and concerns of animal welfare. Though considered to be nutritionally adequate, questions remain over whether current protein recommendations of 0.8 g/kg/d are sufficient to maintain body processes and growth.

Background: Vegan and vegetarian diets have gained in popularity in recent years. Stated reasons for this include some possible health benefits and concerns of animal welfare. Though considered to be nutritionally adequate, questions remain over whether current protein recommendations of 0.8 g/kg/d are sufficient to maintain body processes and growth. Protein is unique in that it is the only macronutrient that contains nitrogen. Its status can be determined through nitrogen balance analysis of the urine if protein content of the diet is known. Nitrogen balance is considered the gold standard for determining protein intake requirements. A negative balance indicates a catabolic state, whereas a positive nitrogen balance is seen during anabolism. In healthy people, nitrogen equilibrium is desired under normal circumstances. This equilibrium reflects the net synthesis and breakdown of proteins. While nitrogen balance techniques have been used for decades, currently, there are no known studies measuring nitrogen balance and protein intake in strict vegans. Methods: Twenty vegan, inactive, male participants were recruited and received a 5-day eucaloric diet with a known protein content held constant at 0.8 g/kg/d. On day five, 24-hour urine was collected by participants and aliquoted for future analysis. Nitrogen content of the urine was determined through photometric assay and compared to the known nitrogen content of the diet to calculate nitrogen balance status. Results: Mean absolute nitrogen balance (-1.38 ± 1.22 g/d, effect size = -1.13) was significantly lower than zero (equilibrium) (p < .001). Mean relative nitrogen balance (-18.60 ± 16.96 mg/kg/d, effect size = -1.10) was significantly lower than zero (p < .001). There were no correlations seen between nitrogen balance and age, years as vegan, or fat- free mass. Conclusion: Consuming 0.8 g/kg/d of protein is insufficient to produce nitrogen balance in long-term vegans.
ContributorsBartholomae, Eric (Author) / Johnston, Carol (Thesis advisor) / Sweazea, Karen (Committee member) / Wharton, Christopher (Committee member) / Lee, Chong (Committee member) / Kressler, Jochen (Committee member) / Arizona State University (Publisher)
Created2022
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Description
Background. Research suggests that non-O blood types are at an increased risk of thrombosis and related health complications in cardiovascular disease (CVD). This is due in part to higher concentrations of von Willebrand factor (VWF), an important factor involved in blood clotting. Objective. The purpose of this study was to

Background. Research suggests that non-O blood types are at an increased risk of thrombosis and related health complications in cardiovascular disease (CVD). This is due in part to higher concentrations of von Willebrand factor (VWF), an important factor involved in blood clotting. Objective. The purpose of this study was to examine the effects of a vegetarian-like diet on blood coagulation and other health parameters in adults with type A blood compared to type O blood over a four week intervention. Given the lack of previous research on blood type and diet, it was hypothesized that no difference in blood coagulation would be observed. Design. This study was a randomized, parallel arm, dietary intervention using healthy, omnivorous adults with blood types A and O. A total of 39 subjects completed the study. Subjects were randomized into two groups: a vegetarian-like diet group made up of 12 type As and 12 type Os and an omnivorous control diet group made up of 11 type As and 12 type Os. At weeks 0 and 4, fasting blood was drawn and analyzed for prothrombin time (PT), activated partial thromboplastin time (APTT), von Willebrand factor (VWF), total cholesterol, LDL, HDL, triglycerides, and CRP. In addition, subjects were weighed and filled out a FFQ at weeks 0 and 4. Results. After adhering to a vegetarian-like diet for four weeks, type Os had a significant increase in PT (+0.24±0.32 sec/ p=0.050), whereas type As saw no significant change. There was a trend of weight loss for type Os in the vegetarian-like diet group (-1.8±2.6 lb/ p=0.092) and significant weight loss for type As (-0.9±2.1 lb/ p=0.037). Both blood types O and A experienced significant decreases in BMI (-0.3±0.4/ p=0.092 and -0.2±0.3/ p=0.037, respectively). No change was seen in APTT, VWF, total cholesterol, LDL, HDL, triglycerides, or CRP. Conclusion. Type Os saw an increase in PT, perhaps indicating a reduction in risk of thrombosis and its related health complications. Type As were less responsive to the dietary intervention and may require more rigid dietary guidelines or a longer time on such a diet to see the benefits.
ContributorsBrown, Jennifer (Author) / Johnston, Carol (Thesis advisor) / Martin, Keith (Committee member) / Shepard, Christina (Committee member) / Arizona State University (Publisher)
Created2013
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Description
Plant-based eaters are known to reap nutritional benefits due to their dietchoice, but it is important to evaluate dietary differences that may put them at a disadvantage compared to omnivores. Stark differences exist in daily intakes of protein between vegans and omnivores, which may lead to several risks including decreased

Plant-based eaters are known to reap nutritional benefits due to their dietchoice, but it is important to evaluate dietary differences that may put them at a disadvantage compared to omnivores. Stark differences exist in daily intakes of protein between vegans and omnivores, which may lead to several risks including decreased strength and bone density. The purpose of this study was to analyze the differences in protein intake, lean mass, strength, and bone density in vegans versus omnivores in order to support the argument for an increased recommended daily allowance (RDA) for protein for plant-based eaters. Participants in this study were assigned to groups based on omnivorous (n = 25) or vegan (n = 19) dietary pattern. Nineteen matched pairs were created based on age and BMI. Data was collected at a single lab visit and included health history and physical activity readiness questionnaires, 24-hr food recall, and anthropometric measures. Bone mineral density (BMD) was measured using DEXA and strength was assessed using hand and Biodex dynamometers. Statistical analyses were conducted using independent samples t-tests and Pearson’s correlation tests to evaluate differences in body composition, bone density, strength, and dietary intake between the two groups with significance set at p.05. Differences were seen in daily calorie (p=.007), protein (p<.001), fat (p<.001), and fiber (p=.009) intake. Lean mass (p=.282) and bone density (p=.651) were not different between groups, but lower body strength was different (p=.008). There was a correlation between lower body strength and protein intake (p<.001), and lean mass was correlated with lower body strength (p<.001), grip strength (p<.001), and bone density (p<.001), but not i LBM (p=0.158). Correlations were also observed between BMD and lower body strength (p=.004). These data suggest that there is a significant difference between protein intake in vegans versus omnivores, which appears to have a positive association with strength. BMD also has a positive association with strength as well as lean mass. Cumulatively, the results suggest that it may be beneficial for vegans to increase daily protein intake.
ContributorsNadalet, Camila R (Author) / Johnston, Carol (Thesis advisor) / Shepard, Christina (Committee member) / Hooshmand, Shirin (Committee member) / Arizona State University (Publisher)
Created2023