SCAN Graduate Student Research Grant Program
NICOLE LITWIN, MS, RD
Nicole Litwin, MS, RD is a PhD candidate in Food Science and Human Nutrition at Colorado State University, specializing in Functional Foods for Health. Nicole holds a BS in Nutrition and Food Science and a MS in Clinical Nutrition from East Tennessee State University, where she also completed her dietetic training. Prior to her PhD, Nicole worked as a consulting dietitian for food companies translating nutrition science into understandable and usable information for consumers, health professionals, and company stakeholders. Nicole’s broad research interests include identifying efficacious dietary interventions to improve vascular function for promoting cardiovascular health and disease prevention. Nicole is an active member in several organizations and has held leadership positions with the Research Dietetic Practice Group of the Academy of Nutrition and Dietetics, the Nutrition Translation Research Interest Section of the American Society for Nutrition, and the Rocky Mountain Section of the Institute of Food Technologists.
Description of Proposed Research Objectives
Cardiovascular disease (CVD) is the leading cause of mortality in postmenopausal women1, largely due to accelerated aging-related modifications to arteries following menopause. One of these adverse arterial changes is the development of vascular endothelial dysfunction, assessed as a decline in endothelium-dependent dilation (EDD). Endothelial dysfunction can lead to increased blood pressure, atherosclerosis, and increased risk of CVD, CVD events, and mortality. Life expectancy is increasing and women are spending more than a third of their lifespan after menopause. Therefore, it is of immense clinical and public health importance to identify evidence-based therapeutic strategies that can preserve and improve endothelial function and therefore reduce CVD risk in postmenopausal women.
Women experience progressive reductions in EDD across stages of the menopausal transition independent of traditional CVD risk factors.3 The loss of estrogen during the menopausal transition is a triggering event for the development of endothelial dysfunction in women, likely due to the important antioxidant and direct regulatory effects of estrogen on the vascular endothelium.3 Elevated blood pressure, which often develops after menopause, has been shown to contribute to and exacerbate endothelial dysfunction.4 Approximately ¾ of postmenopausal women develop hypertension (HTN), further worsening endothelial function and increasing CVD risk.
The primary mechanism underlying endothelial dysfunction is reduced bioavailability of nitric oxide (NO), an endothelium-derived vasodilator and vascular-protective molecule.2 Reduced NO bioavailability with age and menopause is largely driven by the presence of excessive oxidative stress, which develops as a result of increased reactive oxygen species (ROS) production relative to antioxidant defenses.2,3 ROS from various sources (e.g., dysfunctional mitochondria and the superoxide producing enzyme NADPH oxidase) decrease NO bioavailability directly by reacting with NO to form damaging reactive nitrogen species (e.g., peroxynitrite), and indirectly by oxidizing the enzyme endothelial nitric oxide synthase (eNOS) and cofactors required for NO synthesis. Additionally, oxidative stress promotes inflammation, further impairing endothelial function.6 Oxidative stress and inflammation in postmenopausal women have been implicated in endothelial dysfunction, HTN, and atherosclerosis. 5 As such, improving NO bioavailability through targeting oxidative stress and inflammation is a promising approach for improving endothelial dysfunction in this population.
Epidemiological evidence supports a strong, inverse association between dietary intake of polyphenol-rich foods and CVD risk and related mortality.7 Blueberries are rich in polyphenols (e.g., anthocyanins, phenolic acids, stilbenes). These compounds and their metabolites exert strong antioxidant and anti-inflammatory effects in vivo, and preclinical evidence demonstrates that blueberries can attenuate inflammation and oxidative stress, lower blood pressure (BP), activate eNOS signaling, and improve NO bioavailability and endothelial function, thus providing rationale for studying these effects in humans.7 It is presently unknown whether chronic blueberry consumption can improve endothelial dysfunction in postmenopausal women, and the mechanisms by which this effect is mediated. Our laboratory recently demonstrated that consumption of 22 g/day freeze-dried blueberry powder (~1 cup fresh blueberries) for 8 weeks significantly reduced BP and arterial stiffness and increased plasma NO metabolites in postmenopausal women with pre- and stage-1 HTN, 8 suggesting that blueberries may improve endothelial dysfunction in this population. Thus, we are conducting a randomized, double-blind, placebo-controlled, parallel-arm clinical trial to directly assess the efficacy of chronic blueberry consumption for improving endothelial dysfunction, and underlying mechanisms using novel and innovative techniques.
ZACHARY GRUNEWALD, MS, BS, RD
Zachary Grunewald, MS, BS, RD is a PhD candidate in Nutrition and Exercise Physiology at the University of Missouri. He is from Land O’ Lakes, Florida and attended Florida State University for his undergraduate career where he earned bachelor’s degrees in dietetics as well as food and nutrition science. During his time at Florida State, he became involved with research and worked in a cardiovascular laboratory for three years which inspired him to apply to a Master’s degree program. He attended the University of Georgia and was enrolled in a combined Masters of Science and dietetic internship program. After completing his dietetic internship and Master’s degree, he passed the dietetic registration exam in September of 2016. He currently lives in Columbia, Missouri where he attends the University of Missouri as a doctoral student studying exercise physiology with a research emphasis in cardiovascular physiology and obesity.
Description of the Proposed Research Objectives
Obesity and cardiovascular disease remain two of our nation’s leading health concerns (Mozaffarian et al 2016). Major independent risk factors for the development of cardiovascular disease include poor dietary habits and physical inactivity. In animal models and humans, high fat/high caloric diets and physical inactivity are associated with endothelial cell dysfunction, which contributes to impaired vascular function (Mikus et al 2012; Weil et al 2011). Endothelial dysfunction is characterized by elevated production of endothelin-1 (ET-1) secretion, a potent vasoconstrictor, and reduced vasodilatory capacity (Weil et al 2011; Reynolds et al 2017). Moreover, significant evidence in humans and animal models has implicated elevated ET-1 as a contributor to obesity-associated cardiovascular diseases and diabetes (Reynolds et al 2017; Amiri et al 2004). However, the specific actions of ET-1 in these conditions remains unknown.
ET-1 is produced and secreted by the endothelial cells and functions to maintain mean arterial pressure which is critical for oxygen perfusion to organs at rest and during exercise (Barrett-O’Keefe et al 2013). However, ET-1 expression and activity is elevated in chronic diseases such as obesity (Weil et al 2011) and type 2 diabetes (Reynolds et al 2017) and is suggested to contribute to impaired vascular function seen with these conditions (Reynolds et al 2017; Mahmoud et al 2016). Additionally, ET-1 has been demonstrated to play a role in the pathology of many chronic diseases states such as hypertension, oxidative stress, and insulin resistance (Amiri et al 2004; Mikus et al 2012). Evidence in rodents suggest that chronically elevated ET-1 increases vascular remodeling (Amiri et al 2004), oxidative stress (Idris-Khodja et al 2016) and alters adipocyte phenotype (Klepac et al 2016), whereas, aerobic exercise in humans and rodents has been demonstrated to reduce ET-1 levels (Maeda et al 2002; Maeda et al 2003; Mikus et al 2012). However, the extent to which exercise ameliorates ET-1-mediated vascular dysfunction, insulin resistance, and adipose tissue dysfunction remains unknown.
Thus, the proposed research project will aim to determine two objectives 1) identify molecular mechanisms by which elevated ET-1 contributes to Western diet-induced vascular dysfunction, insulin resistance, and adipose tissue phenotype 2) determine the efficacy of regular exercise to ameliorate the detrimental effects of elevated ET-1 on cardiovascular outcomes, insulin resistance, and adipose phenotype following a Western diet challenge. We hypothesize that elevated ET-1 exacerbates Western diet induced vascular dysfunction and insulin resistance and that regular exercise will prevent the development of these chronic conditions. Additionally, we hypothesize that ET-1 contributes to Western diet-induced adipose tissue inflammation and that regular exercise improves adipose tissue phenotype. This proposed research will fill the gaps in the literature about the specific roles of elevated ET-1 in Western diet-induced vascular dysfunction, adipose tissue inflammation, and insulin resistance. Moreover, this research will add to our understanding of how exercise may prevent the development of chronic disease in the face of elevated ET-1 and obesity.
HEIDI LYNCH, MS, RD
Heidi Lynch, MS, RD, is a PhD candidate in Physical Activity, Nutrition, and Wellness at Arizona State University (ASU). Lynch received a BS in Applied Health Science from Wheaton College (IL), and she completed her MS in Nutrition and dietetic internship through ASU. Prior to beginning her PhD, Lynch worked as an outpatient dietitian and taught for two community colleges. Her research interests include integrating plant-based nutrition and athletic performance. In addition to being involved with SCAN, Lynch is Arizona's state coordinator for the Vegetarian Nutrition Dietetics Practice Group and serves on ASU's Graduate and Professional Student Association Wellness Team.
Description of the Proposed Research Objectives
Developing and preserving muscle mass and strength are contributors to success in many athletic events. Since interest in and adherence to plant-based diets continues to grow, it is imperative that we understand how plant-based protein may affect muscle synthesis differently than animal-derived protein. Soy and whey protein have been studied extensively since both are considered "complete proteins." However, there are important differences between soy and whey protein, including the actual amount of various amino acids in each type of protein, their digestibility, and the kinetics of their absorption. Compared to soy protein, whey protein contains more leucine, an amino acid that exerts a greater stimulus for promoting muscle synthesis and reducing muscle breakdown than other amino acids. Whey protein is made of 13.6% leucine, while soy protein only contains 8.0% leucine. Additionally, although soy and whey protein both have Protein Digestibility Corrected Amino Acid Scores (PDCAAS) above 90%, soy protein has not been able to stimulate comparable post-exercise muscle synthesis compared to whey protein when compared on an isonitrogenous basis (thus, the soy protein still contained less leucine). The purpose of this study is to ascertain whether athletes consuming a soy protein supplement can experience comparable muscle mass and strength gains compared to those consuming a whey protein supplement following a 12-week resistance training protocol when protein sources are matched for leucine content.
JACKIE BARCAL, RD, LD
Jackie Barcal, RD, LD is the current Sports Nutrition Graduate Assistant for University of Wyoming Athletics where she is pursuing a master’s in Food Science and Human Nutrition.
Jackie competed in collegiate softball at California State University, Stanislaus in Turlock, CA and it was during this time that her passion for sports nutrition developed. After graduating magna cum laude and earning a bachelor’s degree in business administration finance, Jackie obtained a second bachelor’s degree in dietetics from CSU Sacramento in 2011. She then completed her dietetic internship at CSU Fresno. Jackie was a participant in the inaugural Gatorade/CPSDA Sports Nutrition Immersion Program (SNIP) in 2013 at the University of Alabama in Tuscaloosa where she gained experience working within a Division I athletic program.
Her career goals include obtaining a full time position as a director of sports nutrition and also improving sports nutrition education at the high school level.
Description of the Proposed Research Objectives
Increasing evidence has linked low vitamin D status to a variety of health conditions including osteoporosis, cardiovascular disease, diabetes, depression, multiple sclerosis, rheumatoid arthritis and certain types of cancer [1-3]. Increasing evidence has also linked low vitamin D status to increased susceptibility to upper respiratory tract infections [4, 5] including influenza and the common cold [5, 6]. Although vitamin D is considered a vitamin, it is unique in that it both acts as a hormone, assisting in regulation of serum calcium, and may be obtained from dietary or endogenously synthesized sources. Endogenous synthesis occurs in the skin upon exposure to sufficient ultra violet B (UVB) light [1, 7]. Unfortunately, only a few foods are natural or fortified sources of vitamin D including fatty fish, whole milk, and some brands of yogurt, margarine, fruit juice, and ready-to-eat cereals. Although vitamin D deficiency was once considered a nutritional problem of the past, it has recently re-emerged as a possible public health concern. In fact, some researchers believe it is an unrecognized epidemic in adults who are not exposed to adequate sunlight .
Studies in athletes and active individuals have suggested that vitamin D deficiency can impair strength , prolong recovery from surgery , alter inflammatory markers [10, 11], and increase risk for injury and illness [7, 11, 12, 13,]. Prevalence of vitamin D deficiency varies by sport, training location and skin color . Vitamin D status is generally lower in the winter among athletes who train predominantly indoors versus outdoors [15, 16]. Studies have found a high prevalence of vitamin D deficiency in gymnasts training in East Germany  and Finland  with an estimated 37% to 68% having serum 25(OH)D concentrations under 10-15 ng/mL, indicative of deficient status, and in Middle Eastern sportsmen training close to the equator in Qatar  of whom 91% had serum 25(OH)D concentrations under 20 ng/mL. Athletes with the highest observed status have included college athletes training mostly outdoors from the University of Wyoming [20-22]. To our knowledge, the vitamin D status of wrestlers has not yet been evaluated.
Wrestlers, particularly at the college level, are at risk for skin infections from mat and skin-to-skin contact and prone to compromised immune function due to observed nutrient restriction (personal observation), including key vitamins, minerals, and other dietary antioxidants and anti-inflammatory agents that results from cutting weight. Because wrestling season takes place from October to March, there may be an added risk of vitamin D deficiency and compromised immune modulation. This is a time period of limited sun exposure and when risk of seasonal upper-respiratory infection is likely.
The primary purpose of this study was to assess vitamin D status of male college wrestlers during the academic year, and determine if low vitamin D status (i.e., low circulating concentrations of 25-hydroxy vitamin D) is linked with documented risk of acute illness, including skin infections, and with circulating pro-inflammatory (IL-6 and TNF-alpha) and the anti-inflammatory interleukin-10 (IL-10). The impact of cutting weight on body composition and circulating 25(OH)D will also be assessed using dual-energy x-ray absorptiometry (DXA). The working hypothesis is that wrestlers with suboptimal vitamin D status (25(OH)D < 32 ng/mL) will have a higher incidence of acute illness including skin and upper respiratory tract infections (URTI’s), higher pro-inflammatory markers, and lower anti-inflammatory markers compared to wrestlers with optimal vitamin D status (25(OH)> 40 ng/mL). It is further hypothesized that weight cycling and poor antioxidant intake [10, 13] will impact the above risks independent of vitamin D status. Within the entire group of wrestlers, it is hypothesized that individual athletes with limited sun exposure, low intake of vitamin D, and dark pigmented skin will also be at greater risk for low vitamin D status.
LONA SANDON, MED, RDN, LD
Lona Sandon, MEd, RDN, LD is a PhD candidate of Health Studies at Texas Woman’s University. Her degree includes an emphasis in higher education and wellness programing and evaluation. She is an assistant professor for the masters coordinated program at UT Southwestern Medical Center in Dallas. In addition to her teaching responsibilities, Ms. Sandon serves on the campus employee-wellness committee and is the coordinator of the worksite weight-loss program for employees of UT Southwestern. Ms. Sandon is a past spokesperson of the Academy and is currently serving as the House of Delegates representative for the Nutrition Educators of Health Professionals dietetics practice group. Like many SCAN members, she has a passion for maintaining health and wellness through nutrition and fitness and enjoys motivating others to do the same. She maintains her ACE group fitness and YogaFit certifications with the hopes of getting back to teaching fitness classes regularly upon completing her dissertation.
Description of the Proposed Research Objectives
Ms. Sandon’s study will use a mixed-methods design to assess the influence of a behavior change intervention on self-regulation, self-efficacy and weight change to determine effectiveness in addressing overweight and obesity in a worksite setting and investigate the effect of social influence on these above variables. Greater use of self-regulation, higher self-efficacy, and positive social support are associated with traits likely to support weight loss. Therefore, increasing the degree of self-efficacy, self-regulation, and social support as they relate to healthful eating and exercise behaviors would likely result in greater weight loss success.
Specific objectives are to first quantitatively evaluate the change in self-efficacy and self-regulation for eating and exercise behaviors and weight change during a 10-week worksite weight-loss, theory-based behavior change intervention in adult employees compared to controls. The second objective is to generate themes about participants’ perceptions of how social influence of co-workers may affect change in self-efficacy and self-regulation for eating and exercise behaviors, and weight change using semi-structured interviews. The third objective includes evaluating the relationships of change in self-regulation, self-efficacy, weight, fruit and vegetable intake, and exercise frequency.
JENNIFER BURRIS, MS, RD, CSSD, CNSC, CSG, CDE
Jennifer Burris MS, RD, CSSD, CNSC, CSG, CDE is a Registered Dietitian and Doctoral Candidate in Nutrition at New York University as part of Steinhardt School of Culture, Education, and Human Development in New York, NY. Jennifer received her undergraduate degree in Nutrition Science from University of Arizona in Tucson, AZ. She completed her dietetic internship and master’s degree in Nutrition from California State Polytechnic University, Pomona. She started her dietetic career working as a clinical dietitian in the Burn Intensive Care Unit and Surgical Intensive Care Unit at University of California, Irvine and as a clinical dietitian specializing in long-term care for Dietitians of Orange County. She then went on to work with the Metabolic Disorders and Genetic Inborn Errors of Metabolism at Children’s Hospital Orange County, California, and as a Sports Nutrition Consultant for the Santa Ana College Wellness Program in California.
Jennifer is board certified as a specialist in sports dietetics, nutrition support specialist clinician, specialist in gerontological nutrition and is a certified diabetes educator. Currently, her doctoral research specializes in the role of medical nutrition therapy in skin diseases, especially acne, and sports nutrition.
Description of the Proposed Research Objectives
Acne is a relatively common disease, affecting more than 45 million Americans (1. Although acne may occur for a short period of time, many people suffer for years (1-2). The impact of acne of quality of life is not insignificant and is reported to be similar to patients with chronic disabling asthma, epilepsy, diabetes, and arthritis (3). Effective management enhances patient wellness by improving acne severity as well as the psychological symptoms associated with acne including poor self-esteem and body image, suicidal ideation, and depression (2). Although acne is frequently treated with medications, pharmaceutical management can be be costly and have unwanted side effects (4). The development of additional treatment options to improve the physical effects of acne and promote patient wellness are warranted.
Historically, diet therapy was a routine part of treatment with acne. After a series of influential studies demonstrated diet was not associated with acne, the diet-acne hypothesis fell out of favor (5). More recently, registered dietitians and dermatologists have reevaluated the nutritional influences related to acne development. In particular, the last decade has experienced growth of interest in research investigating the impact of dietary glycemic index (GI) and glycemic load (GL) on acne, including several though-provoking randomized control trials. Most (6-8) but not all (9) studies demonstrate an improvement in acne after consuming a low GL diet. Although these studies provide interesting preliminary data, they have methodological limitations including: failure to account for baseline diet (6-7, 9), changes in body weight (6-7), and potential important confounding dietary factors, such as dietary fat or dietary intake, which may independently impact acne development (6-8). Additional limitations include a lack of generalizability (many studies include only males or young adults) (14-15) and the use of non-validated acne grading methods (9). Moreover, some of these randomized controlled trials did not include a control group and assessed dietary intake just on weekends (9). Taken together, these limitations complicate the interpretations of these innovative studies.
To identify gaps in the literature and determines the appropriate next steps to explore the diet-acne relationship, our research team published a comprehensive review examining the history of diet and acne (5). We also conducted a cross-sectional study investigating differences in diet between groups of self-reported acne among young adults (10). A total of 248 participants completed 2-questionnaires assessing acne severity and usual dietary intake. Participants with moderate and sever acne reported a greater dietary GI and added sugar intake compared to participants with no or mild acne (p<0.001), suggesting diet may influence acne development. In addition, we are currently conducting a case-control study to examine differences blood biochemical markers of acne, insulin resistance, and diet among adults with and without acne. This study will add to the current literature by analyzing 5-day weighed food record, measuring blood biochemical markers of acne, calculating insulin resistance, and measuring acne severity and total lesion counts.
The objectives of the proposed randomized controlled trial are to examine changes in hormonal markers of acne markers of acne among adults following a low GL diet or their usual diet for 2-weeks. Because these blood biochemical markers are associated with acne, changes will suggest diet may augment acne development. Nutrisystem will provide the low GL foods for the 2-week dietary intervention. I am seeking additional support to help fund the laboratory fees and study related costs. The proposed study will lay the foundation to help design and conduct a longer, randomized controlled trial to evaluate the efficacy of diet therapy on acne development. The establishment of evidence based nutrition practices, including diet and acne, are essential to help SCAN members provide effective nutrition counseling and promote patient wellness.
ERIKA RAUK, RD, LN
Erika Rauk, RD, LN is a Master of Science in Exercise Physiology and Nutrition student in the Department of Health and Human Development at Montana State University. Rauk received a BS in Chemistry in May 2004 from the University of Montana and a BS in Food and Nutrition in May 2010 from Montana State University. She was the 2010-2011 ADA Foundation Janette Smith Memorial Scholarship Recipient and completed her Dietetic Internship through Idaho State University in May 2011. She has been published in the Journal of Chromatography, Electrophoresis, and Analytical and Bioanalytical Chemistry.
*Photograph by Whitney Kamman Photography
Description of the Proposed Research Objectives
High fructose corn syrup is an inexpensive glucose and fructose (45% glucose to 55% fructose) mixture containing carbohydrate that is regularly added to sport specific products (SSPs). Manufacturers claim their products containing HFCS enhance athletic performance, but not all SSPs contain HFCS as the CHO source. Yet, the other manufacturers, for example, Powerade compared to Gatorade, still claim their products enhance athletic performance. According to the Nutrient Data Laboratory, Powerade has a 1:3.3 ration of glucose to fructose and Gatorade has a 1.3:1 ratio. Also, because of the scrutiny that HFCS has had with its potential link to the rise in obesity, cardiovascular disease, and metabolic disorders, some manufacturers may avoid utilizing this carbohydrate source. By avoiding HFCS athletes may lose the performance enhancing benefits that HFCS could have to offer. Therefore, the intent of this study is to determine if a HFCS-sweetened beverage is an acceptable CHO source for prolonged moderate to high intensity exercise by determining its affects on the indices of acute exercise metabolism (i.e. lipids, triglycerides, glucose, insulin, and lactate) when compared with a glucose-sweetened beverage in healthy adults.
TANYA HALLIDAY, RD
Tanya Halliday, RD is a 2nd year doctoral student in the Department of Human Nutrition, Foods and Exercise at Virginia Tech. Halliday received a BS in Dietetics in 2010 from the University of Wyoming and in 2011, she completed a Dietetic Internship through the University of Houston. She has presented research at regional and national conferences and has been published in the ACSM journal, Medicine & Science in Sports & Exercise. She has served SCAN as a member of the Symposium Committee, the CV/W Leadership Team, and the Student Group Core Team. She also co-authored the vitamin D Fact Sheet for SD-USA.
Recently, it has been speculated that high added sugar (AS) intake may contribute to cardiovascular disease (CVD). Yet to date, no studies have examined the effect of habitual AS intake on arterial stiffness. Arterial stiffness is an important CVD risk measure because it represents the cumulative damaging consequences of traditional CV risk factors (i.e. – blood pressure, lipids, etc) and can indicate that CV risk is present even when traditional markers are normal. Therefore, the primary goal of this study is to determine if habitual AS intake is associated with arterial stiffness in adults. Measures will include: arterial stiffness; traditional CV outcomes; markers of inflammation and oxidation; and body weight/composition. Habitual AS intake will be evaluated by self-report and an objective blood biomarker of AS intake, δThis project addresses an important gap in the literature related to AS intake, arterial stiffness, and CVD risk. This information is needed to determine if current AS intake recommendations are associated with a more favorable CV risk profile.