Matching Items (5)
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- All Subjects: Health Sciences
- All Subjects: Taste
- Genre: Masters Thesis
- Creators: Lespron, Christy
- Member of: ASU Electronic Theses and Dissertations
Description
ABSTRACT The hormone leptin is an important regulator of body weight and energy balance, while nitric oxide (NO) produced in the blood vessels is beneficial for preventing disease-induced impaired vasodilation and hypertension. Elevations in the free radical superoxide can result in impaired vasodilation through scavenging of NO. Omega 3 is a polyunsaturated fatty acid that is beneficial at reducing body weight and in lowering many cardiovascular risk factors like atherosclerosis. The present study was designed to examine the change in plasma concentrations of leptin, nitric oxide, and the antioxidant superoxide dismutase in addition to examining the association between leptin and NO in healthy normal weight adult female subjects before and following omega 3 intakes. Participants were randomly assigned to either a fish oil group (600 mg per day) or a control group (1000 mg of coconut oil per day) for 8 weeks. Results showed no significant difference in the percent change of leptin over the 8 week supplementation period for either group (15.3±31.9 for fish oil group, 7.83±27 for control group; p=0.763). The percent change in NO was similarly not significantly altered in either group (-1.97±22 decline in fish oil group, 11.8±53.9 in control group; p=0.960). Likewise, the percent change in superoxide dismutase for each group was not significant following 8 weeks of supplementation (fish oil group: 11.94±20.94; control group: 11.8±53.9; p=0.362). The Pearson correlation co-efficient comparing the percent change of both leptin and NO was r2= -0.251 demonstrating a mildly negative, albeit insignificant, relationship between these factors. Together, these findings suggest that daily supplementation with 600 mg omega 3 in healthy females is not beneficial for improving these cardiovascular risk markers. Future studies in this area should include male subjects as well as overweight subjects with larger doses of fish oil that are equivalent to three or more servings per week. The importance of gender cannot be underestimated since estrogen has protective effects in the vasculature of females that may have masked any further protective effects of the fish oil. In addition, overweight individuals are often leptin-resistant and develop impaired vasodilation resulting from superoxide-mediated scavenging of nitric oxide. Therefore, the reported antioxidant and weight loss properties of omega 3 supplementation may greatly benefit overweight individuals.
ContributorsAlanbagy, Samer (Author) / Sweazea, Karen (Thesis advisor) / Johnston, Carol (Committee member) / Shepard, Christina (Committee member) / Lespron, Christy (Committee member) / Arizona State University (Publisher)
Created2014
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
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
The effects of iron and chromium blood concentrations have been linked to blood glucose control in diabetics. It is suggested that iron causes oxidative stress in the beta cells of the pancreas and adipocytes creating insulin insufficiency and resistance. Chromium is believed to increase the action of insulin through its biologically active molecule chromodulin. Both of these mechanisms are not clear. This 20 week case study tests the feasibility of combining iron depletion therapy followed by chromium supplementation to improve insulin sensitivity. This single case study followed a protocol of two blood donations separated by eight weeks followed by chromium supplementation of 250 µg of chromium picolinate once a day four weeks after the second blood donation. Fasting blood draws were taken at baseline, post blood draws and pre and post chromium supplementation. Results were not promising for the first hypothesis of lowering HbA1c, but the results were promising for the second hypothesis of improving insulin sensitivity by lowering the HOMA score.
ContributorsJarrett, Nia (Author) / Johnston, Carol (Thesis advisor) / Lespron, Christy (Committee member) / Mayol-Kreiser, Sandra (Committee member) / Arizona State University (Publisher)
Created2015
Description
There are limited studies exploring the direct relationship between coconut oil and cholesterol concentrations. Research in animals and a few intervention trials suggest that coconut oil increases the good cholesterol (high density lipoprotein, HDL) and thus reduces the risk of cardiovascular disease. Preliminary research at Arizona State University (ASU) has found similar results using coconut oil as a placebo, positive changes in HDL cholesterol concentrations were observed.
The goal of this randomized, double blind, parallel two arm study, was to further examine the beneficial effects of a 2g supplement of coconut oil taken each day for 8 weeks on cholesterol concentrations, specifically the total cholesterol to HDL cholesterol ratio, compared to placebo.
Forty-two healthy adults between 18-40 years of age, exercising less than 150 minutes each week, non smoking, BMI between 22-35 and not taking any medications that could effect blood lipids were recruited from the ListServs at ASU. Participants were randomized to receive either a placebo capsule of flour or a coconut oil capsule (Puritan’s Pride brand, coconut oil softgels, 2g each) and instructed to take the capsules for 8 weeks.
Results indicated no significant change in total cholesterol to HDL ratio between baseline and 8 weeks in the coconut oil and placebo groups (p=0.369), no significant change in HDL (p=0.648), no change in LDL (p=0.247), no change in total cholesterol (p=0.216), and no change in triglycerides (p=0.369).
Blood lipid concentrations were not significantly altered by a 2g/day dosage of coconut oil over the course of 8 weeks in healthy adults, and specifically the total cholesterol to HDL ratio did not change or improve.
The goal of this randomized, double blind, parallel two arm study, was to further examine the beneficial effects of a 2g supplement of coconut oil taken each day for 8 weeks on cholesterol concentrations, specifically the total cholesterol to HDL cholesterol ratio, compared to placebo.
Forty-two healthy adults between 18-40 years of age, exercising less than 150 minutes each week, non smoking, BMI between 22-35 and not taking any medications that could effect blood lipids were recruited from the ListServs at ASU. Participants were randomized to receive either a placebo capsule of flour or a coconut oil capsule (Puritan’s Pride brand, coconut oil softgels, 2g each) and instructed to take the capsules for 8 weeks.
Results indicated no significant change in total cholesterol to HDL ratio between baseline and 8 weeks in the coconut oil and placebo groups (p=0.369), no significant change in HDL (p=0.648), no change in LDL (p=0.247), no change in total cholesterol (p=0.216), and no change in triglycerides (p=0.369).
Blood lipid concentrations were not significantly altered by a 2g/day dosage of coconut oil over the course of 8 weeks in healthy adults, and specifically the total cholesterol to HDL ratio did not change or improve.
ContributorsShedden, Rachel (Author) / Johnston, Carol (Thesis advisor) / Lespron, Christy (Committee member) / Shepard, Christina (Committee member) / Arizona State University (Publisher)
Created2017