Matching Items (6)
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- All Subjects: Athletes
- Genre: Masters Thesis
- Creators: Johnston, Carol
- Status: Published
Description
The unpleasant bitter taste found in many nutritious vegetables may deter people from consuming a healthy diet. We investigated individual differences in taste perception and whether these differences influence the effectiveness of bitterness masking. To test whether phenylthiocarbamide (PTC) `supertasters' also taste salt and sugar with greater intensity, as suggested by Bartoshuk and colleagues (2004), we infused strips of paper with salt water or sugar water. The bitterness rating of the PTC strip had a significant positive linear relationship with ratings of both the intensity of sweet and salt, but the effect sizes were very low, suggesting that the PTC strip does not give a complete picture of tasting ability. Next we investigated whether various seasonings could mask the bitter taste of vegetables and whether this varied with tasting ability. We found that sugar decreased bitterness and lemon decreased liking for vegetables of varying degrees of bitterness. The results did not differ by ability to taste any of the flavors. Therefore, even though there are remarkable individual differences in taste perception, sugar can be used to improve the initial palatability of vegetables and increase their acceptance and consumption.
ContributorsWilkie, Lynn Melissa (Author) / Phillips, Elizabeth D. (Thesis advisor) / Cohen, Adam (Committee member) / Johnston, Carol (Committee member) / Arizona State University (Publisher)
Created2012
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
Epidemiological studies have identified obesity as a risk factor for numerous chronic diseases such as adult onset diabetes, hypertension, and hypercholesterolemia. In both humans and laboratory animals, high-fat diets have been shown to cause obesity. Increases in dietary fat lead to increased energy consumption and, consequently, significant increases in body fat content. CD36 has been implicated in fat perception, preference, and increased consumption, but it is yet to be tested using a behavior paradigm. To study the effect of CD36 on fat taste transmission and fat consumption, four CD36 knockout (experimental) mice and four Black 6 wildtype (control) mice underwent 20 days of fat preference and perception testing. Both groups of mice were exposed to foods with progressively increasing fat content (10%, 12.5%, 15% 17.5%, 20%, 45%) in order to assess the effect of CD36 on fat preference. Afterward, the mice were subjected to an aversive conditioning protocol designed to test the effect of CD36 on fat taste perception; development of a conditioned taste aversion was indicative of ability to taste fat. Especially, knockout mice exhibited diminished preference for and reduced consumption of fat during preference testing and were unable to identify fat taste as the conditioned stimulus during aversive conditioning. A repeated measures ANOVA with Bonferroni correction revealed a significant main effect of group on fat consumption, energy intake, and weight. Linear regression revealed CD36 status to account for a majority of observed variance in fat consumption across both phases of the experiment. These results implicate CD36 in fat taste perception and preference and add to the growing body of evidence suggesting fat as a primary taste.
ContributorsJasbi, Paniz (Author) / Johnston, Carol (Thesis advisor) / Lespron, Christy (Committee member) / Wadhera, Devina (Committee member) / Arizona State University (Publisher)
Created2018
Description
Exposure to sun radiation (SUR) with ambient temperature may be an influencer on athletes’ sweat loss in different environments, but the results are not currently known. The purpose of this study was to determine the effects of SUR on fluid balance (FB) and hydration status (HS) in athletes exercising indoors and outdoors.
Initial FB and HS were assessed in NCAA-DI female soccer athletes (n=10) of a single team in temperate, dry conditions (55-68°F, 18-48% humidity) who were monitored during 3 practices of equal estimated energy expenditure (EE): two outdoors in direct SUR (cold/moderate temperatures) and one indoors without SUR (moderate temperatures). Humidity, temperature, and wet bulb globe temperature (WBGT – a measurement partly based on SUR, including ambient temperature/relative humidity) were recorded using Heat Stress Meters placed in the direct sun or in the shade. Each athlete’s semi-nude dry body weight was recorded before and after exercise. Urine samples were taken before, after, and the morning after. Urine specific gravity (USG) was tested to assess HS. Athletes wore combined heart rate and activity monitors to estimate EE and were provided ad libitum water and/or a zero-calorie sports drink. Their total intake included weights of consumed food and drink. Sweat rate was calculated using body weight change and intakes of liquids minus urine losses/hour.
Two-way repeated measures ANOVA analyzed group-level differences. No significance was found in total FB (1.01±0.32 L/hr) or EE/hr (444±97.1 kcal/hr) across all days (p>0.05). In analyzing individual athlete results, 40% had consistent USG >1.025 (p=0.001) suggesting potential dehydration. These 4 athletes selected water as their beverage, of which is known that consuming only water does not stimulate drinking behavior as does electrolyte drinks. The remaining 60% were overall not dehydrated (USG <1.025) but must be aware of incidental dehydration in hotter temperatures.
The conclusion is that in low-moderate temperatures, athletes self-regulate drinking habits and achieve fluid balance during exercise with or without sun radiation. However, athletes with average USG >1.025 are likely to remain dehydrated in moderate temperatures. The findings suggest that more education would benefit these athletes by ensuring hydration in any environment.
Initial FB and HS were assessed in NCAA-DI female soccer athletes (n=10) of a single team in temperate, dry conditions (55-68°F, 18-48% humidity) who were monitored during 3 practices of equal estimated energy expenditure (EE): two outdoors in direct SUR (cold/moderate temperatures) and one indoors without SUR (moderate temperatures). Humidity, temperature, and wet bulb globe temperature (WBGT – a measurement partly based on SUR, including ambient temperature/relative humidity) were recorded using Heat Stress Meters placed in the direct sun or in the shade. Each athlete’s semi-nude dry body weight was recorded before and after exercise. Urine samples were taken before, after, and the morning after. Urine specific gravity (USG) was tested to assess HS. Athletes wore combined heart rate and activity monitors to estimate EE and were provided ad libitum water and/or a zero-calorie sports drink. Their total intake included weights of consumed food and drink. Sweat rate was calculated using body weight change and intakes of liquids minus urine losses/hour.
Two-way repeated measures ANOVA analyzed group-level differences. No significance was found in total FB (1.01±0.32 L/hr) or EE/hr (444±97.1 kcal/hr) across all days (p>0.05). In analyzing individual athlete results, 40% had consistent USG >1.025 (p=0.001) suggesting potential dehydration. These 4 athletes selected water as their beverage, of which is known that consuming only water does not stimulate drinking behavior as does electrolyte drinks. The remaining 60% were overall not dehydrated (USG <1.025) but must be aware of incidental dehydration in hotter temperatures.
The conclusion is that in low-moderate temperatures, athletes self-regulate drinking habits and achieve fluid balance during exercise with or without sun radiation. However, athletes with average USG >1.025 are likely to remain dehydrated in moderate temperatures. The findings suggest that more education would benefit these athletes by ensuring hydration in any environment.
ContributorsOlzinski, Stephanie (Author) / Wardenaar, Floris (Thesis advisor) / Johnston, Carol (Committee member) / Yudell, Amber (Committee member) / Arizona State University (Publisher)
Created2019
Description
Gastrointestinal (GI) complaints are prevalent among athletes. Fermented foods with pre-or probiotic features may relieve GI symptoms by improving gut health. This study aimed is to examine the impact of a nutritional supplement containing fermented whey protein with Galacto-oligosaccharide (GOS) fiber on GI distress among well-trained athletes over time by analyzing self-reported GI complaints without a control group. This quasi-experimental clinical trial consisted of a 3-week baseline period, reflected by two baseline measurements on Day 1 and Day 22, which was followed by a 3-week intervention period, reflected by a post-intervention measurement on Day 43, in which athletes added 15g of a fermented whey protein product to their diet. The primary outcome was based on the self-reported gastrointestinal symptom rating scale (GSRS), and the secondary outcome was based on a daily questionnaire, in which daily GI complaints and exercise occurrences were reported. Tertiary outcomes included a 24-hour diet recall (ASA24) and self-reported diet quality (REAP). Outcomes obtained during baseline (Day 1 and Day 22 average) were compared to those post-intervention (Day 43). Statistical significance was set at P<0.05. A total of n=50 athletes (24.7±4.5 years) with GI issues were included in the study. Five individual items of the GSRS including abdominal pain, acid reflux, bloating, burping, and loose stools reflected significantly lower scores on Day 43 in comparison to baseline (P≤0.028). A total of 78% reported GI complaints at baseline, and 61% of the participants reported lower GI complaints on Day 43 after supplementation in comparison to baseline (P=0.004). Further research is needed to explore the potential benefits of a hydrolyzed and fermented whey protein with prebiotics in a more controlled setting among athletic populations.
ContributorsClear, Anna Marie Grace (Author) / Wardenaar, Floris (Thesis advisor) / Johnston, Carol (Committee member) / Wharton, Christopher (Committee member) / Arizona State University (Publisher)
Created2023
Description
The assessment and evaluation of dietary intake and nutrition knowledge in female athletes is especially important due to the high prevalence of inadequate intake in this population (Black et al., 2019). This study evaluated 1) the relationship of nutrition knowledge and dietary intake among collegiate female athletes at the National Collegiate Athletic Association (NCAA) Division I, National Junior College Athletic Association (NJCAA), and Club sport levels and 2) the impact of competition level on this relationship as well. Participants (NCAA DI, n=51; NJCAA, n = 36; Club, n = 37) in this study answered two questionnaires, the Nutrition Sport Knowledge Questionnaire (NSKQ) and the Rapid Eating Assessment for Participants (REAP) questionnaire to assess knowledge and dietary intake. Participants also provided anthropometric and demographic information. The NSKQ was scored as a whole and for each of the four subcategories. REAP was scored both by tallying the number of “usually/often” frequency responses and given a numeral score to estimate diet quality. Statistical analysis was conducted using Kruskal-Wallis, Chi-square and Spearman’s correlation tests to compare differences within subgroups of participants and evaluate any relationships that may exist between nutrition knowledge and dietary intake with significance set at p≤0.05. Differences in nutrition knowledge between competition groups were significant, H(2)= 16.94, p< 0.001. NCAA DI (p<0.001) and Club (p<0.001) athletes had higher nutrition knowledge than athletes at the NJCAA level. This was true for overall knowledge as well as knowledge subcategories. However, minimal relationships between nutrition knowledge and dietary intake were found. The overall correlation value was rs(118)= -0.10 (95%CI: -0.28 to 0.08), p>0.05. This suggests those with higher nutrition knowledge did not necessarily have better dietary intake. Improvements in the assessment of nutrition knowledge and quick assessment of dietary quality and the relation between both is needed.
ContributorsSkinner, Jensen Drew (Author) / Wardenaar, Floris (Thesis advisor) / Johnston, Carol (Committee member) / Yudell, Amber (Committee member) / Arizona State University (Publisher)
Created2020