Sara Thomas

Dr. Sara Thomas

orcid

Research Focus & Metrics

Academic Career Length

12Years (2015-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
25 July 2024 in Obesity Pillars
Verified
Journal Article
Open access
SCSandra Christensen
Sandra Christensen
KRKatie Robinson
Katie Robinson
STSara Thomas
Sara Thomas
DWDominique R. Williams
Dominique R. Williams
Obesity and type 2 diabetes mellitus (T2DM) are increasingly common in the United States and worldwide. Because both conditions are associated with serious health consequences, weight reduction is recommended by professional medical and nutrition societies to improve outcomes. Due to the striking efficacy of glucagon-like peptide receptor agonists (GLP-1RAs) and dual mechanism glucose-dependent insulinotropic polypeptide/glucagon-like peptide receptor agonists (GIP/GLP-1RAs) for weight reduction and glycemic control, there is increased utilization for patients with obesity and/or T2DM. Yet, the impact of these medications on dietary intake is less understood. This narrative literature review summarizes clinical studies quantifying and characterizing dietary intake in people with obesity and/or T2DM using GLP-1 or GIP/GLP-1 RAs. Though data from these studies reveal that total caloric intake was reduced by 16-39 %, few studies evaluated the actual composition of the diet. Further research is needed to understand the unique nutritional needs of adults on GLP-1 or dual GIP/GLP-1RAs and to support the development of nutritional guidelines for these individuals.

1 October 2016 in Journal of Lipid Research
Verified
Journal Article
Open access
PDF file
STSara Thomas
Sara Thomas
EHEarl Harrison
Earl Harrison
The xanthophylls, lutein and zeaxanthin, are dietary carotenoids that selectively accumulate in the macula of the eye providing protection against age-related macular degeneration. To reach the macula, carotenoids cross the retinal pigment epithelium (RPE). Xanthophylls and β-carotene mostly associate with HDL and LDL, respectively. HDL binds to cells via a scavenger receptor class B1 (SR-B1)-dependent mechanism, while LDL binds via the LDL receptor. Using an in-vitro, human RPE cell model (ARPE-19), we studied the mechanisms of carotenoid uptake into the RPE by evaluating kinetics of cell uptake when delivered in serum or isolated LDL or HDL. For lutein and β-carotene, LDL delivery resulted in the highest rates and extents of uptake. In contrast, HDL was more effective in delivering zeaxanthin and meso-zeaxanthin leading to the highest rates and extents of uptake of all four carotenoids. Inhibitors of SR-B1 suppressed zeaxanthin delivery via HDL. Results show a selective HDL-mediated uptake of zeaxanthin and meso-zeaxanthin via SR-B1 and a LDL-mediated uptake of lutein. This demonstrates a plausible mechanism for the selective accumulation of zeaxanthin greater than lutein and xanthophylls over β-carotene in the retina. We found no evidence of xanthophyll metabolism to apocarotenoids or lutein conversion to meso-zeaxanthin.

5 November 2020 in Nutrients
Verified
Journal Article
Open access
PDF file
JRJulie Richards
Julie Richards
Mary Beth ArensbergMary Beth Arensberg
Mary Beth Arensberg
STSara Thomas
Sara Thomas
KKKirk Kerr
Kirk Kerr
RHRefaat Hegazi
Refaat Hegazi
MBMichael Bastasch
Michael Bastasch
Malnutrition is prevalent among oncology patients and can adversely affect clinical outcomes, prognosis, quality of life, and survival. This review evaluates current trends in the literature and reported evidence around the timing and impact of specific nutrition interventions in oncology patients undergoing active cancer treatment. Previous research studies (published 1 January 2010–1 April 2020) were identified and selected using predefined search strategy and selection criteria. In total, 15 articles met inclusion criteria and 12/15 articles provided an early nutrition intervention. Identified studies examined the impacts of nutrition interventions (nutrition counseling, oral nutrition supplements, or combination of both) on a variety of cancer diagnoses. Nutrition interventions were found to improve body weight and body mass index, nutrition status, protein and energy intake, quality of life, and response to cancer treatments. However, the impacts of nutrition interventions on body composition, functional status, complications, unplanned hospital readmissions, and mortality and survival were inconclusive, mainly due to the limited number of studies evaluating these outcomes. Early nutrition interventions were found to improve health and nutrition outcomes in oncology patients. Future research is needed to further evaluate the impacts of early nutrition interventions on patients’ outcomes and explore the optimal duration and timing of nutrition interventions.

1 March 2018 in Advances in Nutrition
Verified
Journal Article
Closed access
PDF file
STSara Thomas
Sara Thomas
EJElizabeth J Johnson
Elizabeth J Johnson
Carotenoids are plant pigments commonly found in fruits and vegetables. They are made up of 2 classes, xanthophylls and carotenes. Whereas carotenes are composed of only carbon and hydrogen, xanthophylls include hydroxyl groups, making them slightly more hydrophilic than carotenes. Carotenoids are found throughout the body. Among the carotenoids, the xanthophylls lutein and zeaxanthin selectively accumulate in the eye and brain. In the eye, lutein and zeaxanthin are responsible for the yellow pigment of the macula lutea, along with the nondietary lutein metabolite meso-zeaxanthin (1). Xanthophylls have properties similar to lipids, being insoluble in water, and thus share similar transport mechanisms in the aqueous environment of the body. Many factors affect their bioavailability from the diet, including processing, meal composition and digestive enzyme activity (2). In the digestive tract, xanthophylls are incorporated into micelles and cross the enterocyte by simple passive diffusion or via several proposed lipid transporters. β-Cryptoxanthin, the only provitamin A xanthophyll, is partially cleaved to vitamin A by β-carotene-15,15′-oxygenase, while the other xanthophylls are incorporated into chylomicrons and secreted from the lymph into the blood. Xanthophylls are exclusively transported intact through the blood via lipoproteins and are taken up by tissues via membrane-bound lipid transporters. Very small amounts of the cleavage products of lutein and zeaxanthin are present in human plasma and are called “apocarotenoids” (1). Apocarotenoids are present in foods and there is evidence that they are bioactive in the body. Their presence in the body is either from the diet or by enzymatic activity of β, β-carotene-9′,10′-dioxygenase.

1 August 2021 in Clinical Nutrition ESPEN
Verified
Journal Article
Open access
STSara Thomas
Sara Thomas
CACeleste Alexander
Celeste Alexander
BCBridget A. Cassady
Bridget A. Cassady
Nutritional status is an often-overlooked component in infectious disease severity. Hospitalized or critically ill patients are at higher risk of malnutrition, and rapid assessment and treatment of poor nutritional status can impact clinical outcomes. As it relates to the COVID-19 pandemic, an estimated 5% of these patients require admission to an ICU. Per clinical practice guidelines, nutrition therapy should be a core component of treatment regimens. On account of the urgent need for information relating to the nutritional support of these patients, clinical practice guidance was published based on current critical care guidelines. However, a growing body of literature is now available that may provide further direction for the nutritional status and support in COVID-19 patients. This review, intended for the health care community, provides a heretofore lacking in-depth discussion and summary of the current data on nutrition risk and assessment and clinical practice guidelines for medical nutrition therapy for hospitalized and critically ill patients with COVID-19.

5 June 2024 in Frontiers in Clinical Diabetes and Healthcare
Verified
Journal Article
Open access
PDF file
STSara Thomas
Sara Thomas
BBBeth Besecker
Beth Besecker
YCYong Choe
Yong Choe
ECElena Christofides
Elena Christofides
Introduction: Minimizing postprandial glucose response is an important goal for overall diabetes management. Diabetes-specific nutritional shakes (DSNS) have been clinically shown to minimize postprandial glucose response in people with type 2 diabetes (T2DM) compared to high-glycemic foods. However, it is unknown how a high-protein, low-fat DSNS impacts the GLP-1 response.Methods: We tested the postprandial glucose, insulin, and GLP-1 response to a high-protein, low-fat diabetes-specific nutritional shake (DSNS-HP) compared to isocaloric instant oatmeal (IOM) in a randomized, controlled, crossover study in adults with T2DM (n = 24). Participants were randomly selected to receive IOM or DSNS-HP on two test days. Glucose, insulin, and total GLP-1 concentration were measured at baseline and 15, 30, 45, 60, 90, 120, 180, and 240 min postprandially.Results: Compared to IOM, the glucose-positive area under the curve (pAUC) was significantly lower (P = .021). DSNS-HP significantly increased GLP-1 pAUC response by 213% (P <.001) with a corresponding increase in insulin pAUC (P = .033) compared to IOM.Discussion: A high-protein, low-fat DSNS leads to favorable changes in GLP-1 response and is a suitable option to minimize blood glucose response in people with type 2 diabetes.