Matching Items (9)
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- All Subjects: Acetic Acid
- All Subjects: Protein
- Genre: Academic theses
- Creators: Johnston, Carol
- Member of: Theses and Dissertations
- Status: Published
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
Many people with or at risk for diabetes have difficulty maintaining normal postprandial blood glucose levels (120-140 mg/dl). Research has shown that vinegar decreases postprandial glycemia. The purpose of this study was to examine a possible mechanism by which vinegar decreases postprandial glycemia, particularly the effect of vinegar ingestion on gut fermentation. In this parallel arm randomized control trial, the effects of daily ingestion of vinegar on gut fermentation markers were observed among adults at risk for type 2 diabetes in Phoenix, Arizona. Subjects (n=14) were randomly assigned to treatments consisting of a vinegar drink (1.5g acetic acid) or a placebo (2 vinegar pills containing 40mg acetic acid each). All participants were required to consume the vinegar drink (16 oz) or 2 placebo pills every day for 12 weeks. At week 12, participants filled out a questionnaire to report gastrointestinal (GI) symptoms and three consecutive breath samples were taken from each subject to measure fasting breath hydrogen (BH2) with a breath analyzer. Fasting BH2 measures for the vinegar drink group (16.1+11.8 ppm) were significantly different than those from the pill group (3.6+1.4) with a partial eta squared of 0.39 (p=0.023). After adjusting for age as a confounding factor (r=0.406) and removing an outlier, fasting BH2 measures for the vinegar drink group (4.3+1.1 ppm) were still significantly different than those from the pill group (3.6+1.4) with a partial eta squared of 0.35 (p=0.045). Participants in both groups reported mild changes in GI symptoms. In conclusion, adults at risk for type 2 diabetes that consume 2 tablespoons of vinegar a day may have increased gut fermentation compared to those who do not consume vinegar.
ContributorsWhite, Serena (Author) / Johnston, Carol (Thesis advisor) / Appel, Christy (Committee member) / Martin, Keith (Committee member) / Arizona State University (Publisher)
Created2013
Description
To date, there have not been any studies in a human population that explore the potential of vinegar ingestion in reducing visceral fat, a common yet serious metabolic disease risk factor. However, previous research in animal models exhibit promising findings, showing that vinegar is effective at reducing visceral fat. This is thought to be due to the activation of AMPK (adenosine monophosphate protein kinase) by acetic acid, the active ingredient in vinegar. The purpose of this study was to identify if this potentially groundbreaking relationship exists in human subjects. Healthy, nonsmoking, sedentary adults between the ages 18-45 y and a waist circumference measurement greater than or equal to 33 inches for women and 38 inches for men were recruited for this study. Twenty-three participants completed this 8-week, parallel arm, randomized control trial that tested the efficacy of red wine vinegar consumption (2 tablespoons red wine vinegar, twice per day, before a meal; providing 3.6 g acetic acid) against a placebo (1 apple cider vinegar pill, twice per day, before a meal; providing 0.0225 g acetic acid) for 8 weeks. Participants were randomized into either the vinegar (VIN) or control (CON) group after being stratified by age, gender, waist circumference, and weight. Results found that the VIN group experienced a 2% decrease in visceral fat (cm3, quantified by a DXA scan), but this change did not differ significantly from that of the CON group (p=0.256). The VIN group also experienced a slight decrease in insulin compared to the CON group, but this change was not significantly different than the control change (p=0.125). However, the change in HOMA-IR trended downward in the VIN group (-16%) as compared to the CON group (+9%) (p=0.079) with a large effect size, 0.153. Other parameters did not show statistically significant results between the groups. Further research is indicated in order to examine the potential of vinegar to reduce visceral fat.
ContributorsBaker, Olivia (Author) / Johnston, Carol (Thesis advisor) / Mayol-Kreiser, Sandra (Committee member) / Lespron, Christy (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
Objectives: To investigate the potential of vinegar supplementation as a means for reducing visceral fat in healthy overweight and obese adults, and to evaluate its effects on fasting blood glucose and fasting insulin.
Subjects and Methods: Forty-five sedentary overweight and obese adult participants with a waist circumference greater than 32 inches for women and 37 inches for men were randomly assigned to one of two groups, the vinegar group (VIN, n=21) or the control group (CON, n=24), and instructed to consume either two tablespoons of liquid red wine vinegar (3.6g acetic acid) or a control pill (0.0225g acetic acid) twice daily at the beginning of a meal for 8 weeks. Participants were also instructed to maintain normal diet and physical activity levels. Anthropometric measures, dual-energy x-ray absorptiometry (DXA) scans, blood samples, and 24-hour dietary recalls were collected at baseline and at end of trial. A compliance calendar was provided for daily tracking of vinegar supplementation.
Results: Compliance to vinegar supplementation averaged 92.7 ±13.3% among the VIN group and 89.1 ±18.9% among the CON group. There were no statistically significant differences in anthropometric measurements between baseline and week 8: weight (P=0.694), BMI (P=0.879), and waist circumference (P=0.871). Similarly, DXA scan data did not show significant changes in visceral fat (P=0.339) or total fat (P=0.294) between baseline and week 8. The VIN group had significant reductions in fasting glucose (P=0.003), fasting insulin (P <0.001), and homeostatic model assessment of insulin resistance scores (P <0.001) after treatment.
Conclusions: These data do not support the findings from previous studies that indicated a link between vinegar supplementation and increased fat metabolism, specifically visceral fat reduction.
Subjects and Methods: Forty-five sedentary overweight and obese adult participants with a waist circumference greater than 32 inches for women and 37 inches for men were randomly assigned to one of two groups, the vinegar group (VIN, n=21) or the control group (CON, n=24), and instructed to consume either two tablespoons of liquid red wine vinegar (3.6g acetic acid) or a control pill (0.0225g acetic acid) twice daily at the beginning of a meal for 8 weeks. Participants were also instructed to maintain normal diet and physical activity levels. Anthropometric measures, dual-energy x-ray absorptiometry (DXA) scans, blood samples, and 24-hour dietary recalls were collected at baseline and at end of trial. A compliance calendar was provided for daily tracking of vinegar supplementation.
Results: Compliance to vinegar supplementation averaged 92.7 ±13.3% among the VIN group and 89.1 ±18.9% among the CON group. There were no statistically significant differences in anthropometric measurements between baseline and week 8: weight (P=0.694), BMI (P=0.879), and waist circumference (P=0.871). Similarly, DXA scan data did not show significant changes in visceral fat (P=0.339) or total fat (P=0.294) between baseline and week 8. The VIN group had significant reductions in fasting glucose (P=0.003), fasting insulin (P <0.001), and homeostatic model assessment of insulin resistance scores (P <0.001) after treatment.
Conclusions: These data do not support the findings from previous studies that indicated a link between vinegar supplementation and increased fat metabolism, specifically visceral fat reduction.
ContributorsGonzalez, Lisa Ann (Author) / Johnston, Carol (Thesis advisor) / Mayol-Kreiser, Sandra (Committee member) / McCoy, Maureen (Committee member) / Arizona State University (Publisher)
Created2019
Description
Background: Acetic acid in vinegar has demonstrated antiglycemic effects in previous studies; however, the mechanism is unknown.
Objective: To determine whether acetic acid dissociates in the addition of sodium chloride and describe a flavorful vinaigrette that maintains the functional properties of acetic acid.
Design: Phase I - Ten healthy subjects (23-40 years) taste tested five homemade vinaigrette and five commercial dressings. Perceived saltiness, sweetness, tartness, and overall tasted were scored using a modified labeled affective magnitude scale. Each dressing was tested three times for pH with a calibrated meter. Phase II – Randomized crossover trial testing six dressings against a control dressing two groups of nine healthy adult subjects (18-52 years). Height, weight and calculated body mass index (BMI) were performed at baseline. Subjects participated in four test sessions each, at least seven days apart. After a 10-hour fast, participants consumed 38g of the test drink, followed by a bagel meal. Capillary blood glucose was obtained at fasting, and every 30 minutes over a 2-hour period the test meal.
Results: Dressing pH reduced as sodium content increased. In the intervention trials, no significant differences were observed between groups (p >0.05). The greatest reduction in postprandial glycemia (~21%) was observed in the dressing containing 200 mg of sodium. Effect size was large in both group 1 (η2=0.161) and group 2 (η2=0.577).
Conclusion: The inclusion of sodium into acetic acid may impair its ability to attenuate blood glucose after a meal.
Objective: To determine whether acetic acid dissociates in the addition of sodium chloride and describe a flavorful vinaigrette that maintains the functional properties of acetic acid.
Design: Phase I - Ten healthy subjects (23-40 years) taste tested five homemade vinaigrette and five commercial dressings. Perceived saltiness, sweetness, tartness, and overall tasted were scored using a modified labeled affective magnitude scale. Each dressing was tested three times for pH with a calibrated meter. Phase II – Randomized crossover trial testing six dressings against a control dressing two groups of nine healthy adult subjects (18-52 years). Height, weight and calculated body mass index (BMI) were performed at baseline. Subjects participated in four test sessions each, at least seven days apart. After a 10-hour fast, participants consumed 38g of the test drink, followed by a bagel meal. Capillary blood glucose was obtained at fasting, and every 30 minutes over a 2-hour period the test meal.
Results: Dressing pH reduced as sodium content increased. In the intervention trials, no significant differences were observed between groups (p >0.05). The greatest reduction in postprandial glycemia (~21%) was observed in the dressing containing 200 mg of sodium. Effect size was large in both group 1 (η2=0.161) and group 2 (η2=0.577).
Conclusion: The inclusion of sodium into acetic acid may impair its ability to attenuate blood glucose after a meal.
ContributorsBonsall, Amber K (Author) / Johnston, Carol (Thesis advisor) / Mayol-Kreiser, Sandra (Committee member) / Lespron, Christy (Committee member) / Arizona State University (Publisher)
Created2017
Description
Objective: This research examined the impact of daily ingestions of commercial high protein nutrition bars (with or without added fiber) on 24-h energy intake and satiety
for one week among free-living young healthy adults.
Design: In a 4-week double-blind, randomized crossover trial, 21 normal and
overweight participants (Mean BMI 23.9 ± 2.7 kg/m²), free of chronic diseases, were
randomized assigned to HP (high protein: 21 g protein) or HPHF (high protein high fiber:
20g, 14 g fiber) nutrition bars. Participants were included in the trial if they meet the
criteria for non-smoking, and not taking prescribed medication for chronic diseases.
Participants were instructed to consume commercial nutrition bars daily for seven
consecutive days. Body composition was measured with a bioelectrical impedance scale
at weeks 1, 3, and 5. Dietary data was recorded by the MyFitnessPal app on Wednesday,
Friday, and Sunday of each week.
Results: The mean energy intake for the weeks HPHF bars were consumed is
significantly higher compared to baseline (1998 ± 534 vs. 1806 ± 537 respectively; p =
0.035). The mean fat mass following one week of HPHF bar consumption was
significantly higher than the baseline value (18.8 ± 6.8 vs. 18.3 ± 6.7 respectively; p =
0.023) and trended higher (18.8 ± 6.8 vs. 18.3 ± 6.7 respectively; p = 0.057) in
comparison to the value following one week of HP bar consumption. For the high
physical activity level group (n = 10), the mean energy intakes for the baseline week and
the weeks the HP and HPHF bars were consumed were 1883 ± 597 kcal, 2154 ± 712 kcal,
and 2099 ± 603 kcal respectively (p ˂ 0.04; energy intakes for both bars were
significantly different from baseline). Nutrient intakes differed significantly mirroring the
nutrient profile for each specific bar. There are significant effects after both bars on
satiety, but there were no differences between each bar.
Conclusions: Sales of nutrition bars gained rapid growth and may represent a
unique source for specific nutrients. However, ingestion of commercial high protein
nutrition bars may increase the risk of gaining fat mass and eventual body mass over
time.
ContributorsPang, Minghan (Author) / Johnston, Carol (Thesis advisor) / Shepard, Christina (Committee member) / Alexon, Christy (Committee member) / Arizona State University (Publisher)
Created2022
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 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
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. 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