Nutrition Commons^™

The Role Food Security, Financial Literacy, And Nutrition Literacy Play On The Diet Quality Of College Students, Amelia Sullivan

Electronic Theses and Dissertations

This research aimed to explore the roles of food security status (FSS), financial literacy (FL), and nutrition literacy (NL) on the diet quality (DQ) of college students at the University of Maine. This research additionally sought to understand mediational relationships among these factors that could impact DQ.

A cross-sectional convenience sample of college students completed an online questionnaire assessing sociodemographic factors, short healthy eating index (sHEI)-score, FSS, FL, and NL. Participants' continuous data were analyzed using a Pearson correlation. Differences between interactive NL and sHEI-score while controlling for gender and meal plan differences were analyzed using a MANCOVA. Additionally, differences …

The Relationship Between Intuitive Eating And Body Mass Index And Diet Quality In College Students, Ashley A. Reynolds

Electronic Theses and Dissertations

Objective

The objective of this research was to explore the influence of intuitive eating (IE) on body mass index (BMI) and diet quality (DQ) among college students.

Methods

A cross-sectional convenience sample of college students completed an online survey consisting of the short-Healthy Eating Index (SHEI) and the Intuitive Eating Scale-2 (23 items). Body mass index was calculated using self-reported height and weight. Descriptive statistics were used to assess group characteristics. A linear regression was used to test if IE scores significantly predicted BMI. An independent t-test was used to compare BMIs of students with IE scores above and below …

Educating Dietetics Students About The Nutritional Concerns Of Older Adults, Lily Brickman

Electronic Theses and Dissertations

The percentage of individuals in the United States who fall within the 65 years and older cohort is anticipated to increase substantially over the next decade due to the large baby boomer generation aging into this category by 2030. Consequently, the healthcare demands of older adults are expected to increase, and medical and healthcare providers must be educated and prepared to meet the unique needs of this population. The purpose of this study is to help learn why interest in FSN 406 Nutritional Care of Older Adults has been so low since its inception in 2020, and whether other institutions …

Telomerase Reverse Transcriptase Marks A Novel Population Of Adult Stem Cells In The Mouse Brain That Respond To Metabolic Interventions By Modulating Adult Brain Plasticity, Gabriel S. Jensen

Electronic Theses and Dissertations

Telomerase reverse transcriptase (TERT) is expressed by quiescent adult stem cells (qASC) in numerous adult murine and human tissues but has never been explored in the adult brain. Here, these data demonstrate that TERT+ cells in the adult mouse brain represent a novel population of multipotent qASCs. TERT+ cells were localized to numerous classical neuro/gliogenic niches including the ventricular-subventricular zone, hypothalamus and olfactory bulb, as well as newly discovered regions of adult tissue plasticity such as the meninges and choroid plexus. TERT+ cells expressed neural stem cell markers such as Nestin and Sox2, but not markers of activated stem/progenitor cells, …

The Role Of Red Raspberry (Rubus Idaeus) On Inflammation, Lipid Metabolism, And Endothelial Dysfunction As Related To The Metabolic Syndrome, Natalie Vandenakker

Electronic Theses and Dissertations

Metabolic syndrome (MetS) is major public health concern. Diet can play a major role in the prevention and/or progression of the MetS. At 8 weeks of age, male obese Zucker rat (OZR) and their lean littermates (LZR) were placed on a control or an 8% w/w whole red raspberry (WRR)-enriched diet for 8 weeks. Circulating levels of inflammatory cytokines and their gene expression in the liver and adipose tissue were evaluated. Several lipid markers were measured in the plasma, liver and adipose tissue. The expression of eight genes related to lipid metabolism were evaluated, both in liver and adipose tissue. …

Expanding Our Understanding On Feed Spoilage And Developing Novel Approaches For Its Mitigation, Marjorie A. Killerby

Electronic Theses and Dissertations

The main objective of this study is to improve the understanding and awareness of conserved feed spoilage and to develop novel technologies that can prevent it. In chapter 1, we conducted a meta-analysis to evaluate the effects of chemical (50 articles)and biological (21 articles)preservatives on hay spoilage during storage. Multi-level linear mixed-effects modelswere fit including moderators:Preservative Class (PC), forage type (FT); moisture class (MC), and application rate (AR). Dry matter (DM) loss was affected by PC×FT (P=0.045), PC×AR (P<0.001), and PC×MC (P=0.009),relative to the overall effect of preservatives (-0.37% units). DM loss in propionic acid (PropA)-treated hay was numerically reduced to a greater extent in grasses (-16.2), followed by mixed hay (-1.76), but it was actually increased (+2.2%)in legume hay.Increasing ARof PropA resulted in decrease in DM loss (β = -1.34).Application ofBuffered Organic Acids,Other Organic Acids, PropA,and Anhydrous Ammoniadecreased visual moldiness by -22.1, -29.4, -45.5 and -12.2% units, respectively (PC; P<0.001). Sugars increased in treated grass hay (+1.9) and decreased in treated legume hay -0.8% DM, respectively (P<0.001). Microbial inoculants had small effects on hay spoilage since the overall DM loss effect size was - 0.21%. Inoculated grass hay preserved moresugars (+1.47) than treated legume hay (+0.33) relative to untreated hay (x=4.63% DM; P<0.001). In conclusion, organic acid-based preservatives effectively prevent spoilage of hay as influenced by FT, MC and AR, but microbial inoculants had only small effects. In chapter 2, we evaluated the effects of chemical and biological preservatives and ensiling stage on spoilage, ruminal in vitro fermentation, and methane production of wet brewer’s grain (WBG) silage. Treatments (TRT) were sodium lignosulfonate at10 g/kg (NaL1) and 20 g/kg (NaL2; fresh WBG), propionic acid at 5 g/kg fresh WBG (PRP, 99%), a combination inoculant (INO; Lactococcus lactisand Lactobacillus buchneri each at 4.9 log cfu/fresh WBG g), and untreated (CON). Three stages (STG) were tested:treated WBG (Fresh) was ensiled for 60 d(Ensiled), after which they were opened and aerobically exposed for 10 d (AES). Data were analyzed as a RCBD (5 blocks) with a 5 TRT × 3 STG(Fresh, Ensiled and AES) factorial arrangement. Our results show that Ensiled PRP-treated WBG markedly preserved more sugars (250) and starch (190) than all other Ensiled TRT (x=136 ± 16.2sugarsg/kg DM and x=121 ± 6.15 starch g/kg DM, respectively; P<0.001). Due to its superior nutritive value, PRP-treated AES was less aerobically stable than CON (61.9 vs. 90.1 h; P = 0.03). Preservation was not improved by INO, NaL1 or NaL2, but the latter prevented the increase of neutral detergent fiber (NDF)across STG (x=384).In vitro ruminal fermentation of Fresh WBG resulted in higher methane concentration (0.94) and yield (0.27) than theother STG (x=0.84 ± 0.07mMand x=0.23 ± 0.03mmol/g fermented OM, respectively). In conclusion, PRP was the most effective at preserving WBG during ensiling but failed to improve aerobic stability. In chapter 3, we evaluated the effects of application rate (AR) of sodium lignosulfonate (NaL) and propionic acid(PRP)on high moisture alfalfa hay spoilage during storage and its nutritive value. Treatments (TRT; NaL and PRP) were applied at four AR: 0 (CON), 2.5, 5 and 10 g/kg (fresh basis) to alfalfa hay at 68.5% DM, packed into mini balesand stored for 33 d.Data were analyzed as a RCBD(5 blocks) with a 2 TRT x 4 AR factorial arrangement. At d 33, DM losses were decreased by PRP at 5 and 10 g/kg (0.9), vs.CON (6.92) andNaL (6.63 ± 1.13%). Visual moldiness (0-10) and mold counts were also decreased by PRP at 5 (2.4 and 5.30) and 10 g/kg (0 and 2.7) relative to CON (6.0 and 7.13) and NaL (5.85 ± 0.67 and 7.21 ± 0.31 log cfu/fresh g, respectively). Both TRT increased apparent in vitroDM digestibility at all AR relative to CON (x=543 vs 501 ± 12.0g/kgof DM, respectively), but the acetate-to-propionate ratio was higher for NaL at 10 g/kg (3.02) vs. CON (2.89 ± 0.04). In conclusion, NaL failed to prevent spoilage of high moisture alfalfa hay while PRP was effective at doses >5 g/kg. Both TRT at 10 g/kg improved the rumen in vitro fermentation measures of high moisture alfalfa hay but PRP …

Fermentation Of Carcinus Maenas As A Method Of Waste Stream Valorization, Delaney M. Greiner

Electronic Theses and Dissertations

The European green crab, Carcinus maenas, is an aggressive invasive species of green crab that has had severe ecological and economic effects to the North American East Coast since the early 1800s. The green crab has disrupted entire ecosystems, particularly in the Gulf of Maine, due to its eating and uprooting of eel grass. The disruption of this plant reduces coastal habitats for bivalves and other coastal marine life. The green crabs have also been found to prey on juvenile lobsters and bivalve mollusks, disrupting both the ecosystem in the Gulf of Maine and the seafood economy dependent on lobsters …

To Know The Land With Hands And Minds: Negotiating Agricultural Knowledge In Late-Nineteenth-Century New England And Westphalia, Justus Hillebrand

Electronic Theses and Dissertations

Ever since the eighteenth century, experts have tried to tell farmers how to farm. The agricultural enlightenment in Europe marked the beginning of a long arc of new experts aiming to change agricultural knowledge and practice. This dissertation analyzes the pivotal period in the late nineteenth and early twentieth century in Germany and the United States when scientists, improvers, and market agents began to develop comprehensive ways to communicate agricultural innovation to farmers. In a functional approach to analyzing the negotiation of agricultural knowledge through its communication in things, words, and practices, this dissertation argues that the process of change …

Adsorptive Surface Modification Of Cellulose Nanocrystals To Stabilize Nutraceuticals Loaded Lipid Carriers For Food Application, Avinash S. Patel

Electronic Theses and Dissertations

Lipid carriers such as emulsions and liposomes have been widely studied as carriers for different nutraceuticals. However, lipid carriers' physicochemical instability results in the leakage of loaded nutraceuticals and the low solubility into the digestion medium, thus reducing the bioaccessibility. Cellulose nanocrystals (CNC) are nano-sized cellulose derivatives obtained after hydrolysis of cellulosic matrices that possess potential applications in functional foods and nutraceuticals. However, hydrophilicity, anionic surface potential, and poor re-dispersibility limit CNC’s applications. The primary objectives of this research were 1) to modify CNC via adsorbing polyethylene glycol (PEG) to stabilize liposomes and to study its physiochemical stability at different …

Development Of Valuable And Functional Protein-Based Food Ingredients From Invasive Green Crabs, Bouhee Kang

Electronic Theses and Dissertations

European green crabs (Carcinus maenas L.) are an invasive species unintentionally introduced from Europe to the U.S. Their predation and burrowing activities have had detrimental effects on our marine habitats, aquaculture, and commercially important fisheries. Despite the large population of green crabs, they are not commercially utilized in North America as food products. The specific objectives of my research were to: 1) determine functional properties of protein recovered from green crab by isoelectric solubilization and precipitation (ISP) for potential food application, 2) investigate the application of enzymatic hydrolysis for deriving bioactive compounds from green crab proteins and examine the …

Consumer Acceptability Of Gulf Of Maine Sugar Kelp Seaweed In Baked Bread, Laurel Simone

Electronic Theses and Dissertations

Although steady interest in edible seaweed cultivation continues to grow in Maine, research is lacking regarding consumer preferences and purchasing behavior of seaweed-containing products. The purpose of this study was to determine consumer acceptability of seaweed baked bread and provide insights into purchasing behavior to reveal potential consumer groups that are most likely to buy and eat baked products containing seaweed. Consumer preferences were determined by a sensory evaluation test and an online survey.

Sixty-five participants completed the central location test of freshly-baked bread containing seaweed. Participants were required to be at least 18 years of age, willing to eat …

Investigation Of Anti-Inflammatory And Antioxidants Properties Of Phenolic Compounds From Inonotus Obliquus Using Different Extraction Methods, Weaam A.A. Alhallaf

Electronic Theses and Dissertations

Inonotus obliquus, commonly known as Chaga, is a fungal pathogen of birch trees, known to synthesize a range of phenolic compounds with remarkable health benefits. These presumed medicinal properties have generated increased interest in Chaga consumption. Prior research has demonstrated the diverse chemical composition of Chaga sourced from a variety of geographical locations. However, to our knowledge, there is currently no available literature regarding the extraction of bioactive compounds from Chaga grown in the United States. Additionally, the effect of the extraction method on the antioxidant and anti-inflammation properties specifically, has yet to be validated. Therefore, the present study was …

Identification Of High-Risk Food Coping Strategies Of Maine Food Pantry Clients, Kathryn Cutting

Electronic Theses and Dissertations

Food coping strategies are strategies adopted by individuals in order to obtain enough food for themselves and their family. Food coping strategies can range from using coupons (couponing) and buying in bulk to skipping meals and stealing food. Although not all strategies are considered to be high risk, all strategies should be accounted for so that nutrition education programming caters to strategies that individuals are employing. This topic has not been widely researched in the United States. The purpose of this study was to identify common food coping strategies of food pantry clients across nine counties in Maine, explore identified …

Assessing The Effectiveness Of The Expanded Food And Nutrition Education Program On Diet Quality As Measured By The Healthy Eating Index 2005, Sarah A. Perkins

Electronic Theses and Dissertations

Background:The Expanded Food and Nutrition Education Program (EFNEP) is a federally funded program through the United States Department of Agriculture that offers nutrition education to low income families across the U.S.

Purpose:This study assessed the effectiveness of Maine EFNEP on food-related behavior change and diet quality as measured by the Healthy Eating Index-2005 (HEI). This study also explored the relationship between the results on the HEI and participation in food assistance programs such as Supplemental Nutrition Assistance Program (SNAP) and Women, Infants, and Children (WIC), as well as the number of hours spent in the program.

Methodology:This study was a …

The Effect Of Wild Blueberry Bioactives On Endothelial Cell Migration And Angiogenesis: An In Vitro Mechanistic, Genomic And Proteomic Approach, Panagiotis Tsakiroglou

Electronic Theses and Dissertations

The goal of this study is to investigate the effects of wild blueberry fractions (Anthocyanins and Phenolic acids) on vascular function and physiology. More specifically the potential effects of the above fractions and their combination in physiological concentrations on endothelial cell migration, angiogenesis, gene expression and proteins synthesis of markers related to the above processes. The objectives are to study whether anthocyanins, phenolic acids and their combinations (ACNs:PAs) affect: a) cell proliferation, b) speed of endothelial cell migration, c) angiogenesis, d) gene expression of genes critical for cell migration and angiogenesis such as RAC1, RHOA, AKT1, eNOS and VEGF and …

Development Of Kefir Products Using Aronia Or Elderberries And The Impacts Of Fermentation On The Health-Promoting Characteristics Of Aronia Polyphenols, Xue Du

Electronic Theses and Dissertations

Diabetes is a global health problem. The consumption of dietary polyphenols may help to decrease the risk of type 2 diabetes and slow the progression of diabetic complications. Aronia (Aronia melanocarpa) and elderberry (Sambucus nigra L. ssp. canadensis) fruits are rich in polyphenols and exhibit health-promoting properties, but they are underutilized. Aronia and elderberries are rarely consumed raw due to the astringent mouth feel. New food products are needed to increase their consumption. Kefir, a fermented dairy beverage, was chosen to be the matrix for incorporating berries due to: 1) the protein matrix can help …

Flower Visitation In Relation To Pollen And Nectar Nutrition: Implications For Pollinator Habitat And Conservation, Megan E. Leach

Electronic Theses and Dissertations

Pollination of both wild and crop plants is at a crossroads; honey bee populations are experiencing losses at a higher rate than ever before, and some native bee species are declining in abundance to the point of being listed as endangered species. A few examples of these threats include pesticide exposure, habitat loss, and climate change. In response to bee population declines, conservation efforts have been initiated to increase habitat quality for bees by planting pollinator reservoirs or gardens. Plants provide nutrition to bees in the form of pollen and nectar. Several studies have shown links between higher nutritional quality …

The Effect Of Wild Blueberry Anthocyanins And Phenolic Acids On Innate Immunity: The Compliment System, Vasiliki Papakotsi

Electronic Theses and Dissertations

Ingestion of berries containing polyphenols is associated with lower risk of inflammatory, metabolic, cardiovascular and degenerative diseases. Diet has been shown to modulate the activation of the complement system, a set of over 50 proteins present in the circulation and tissues that reacts in response to damage or microbial encounter and is critical for the maintenance of homeostasis. Imbalanced activation is tightly correlated with inflammation and various pathologies. Wild blueberries are a rich source of anthocyanins and phenolic acids, which can be found in plasma shortly after consumption. Given the involvement of both complement and polyphenols in the modulation of …

Development Of A Bacteriophage-Based Portable Biosensor For The Detection Of Shiga-Toxin Producing Escherichia Coli (Stec) Strains In Food And Environmental Matrices, Irwin A. Quintela

Electronic Theses and Dissertations

A fast and reliable on-site foodborne pathogens screening can reduce the incidence of foodborne illnesses, hospitalizations and economic loss. It can also circumvent conventional laboratory-based tests with minimal sample treatments and shorter turnaround time. Rapid detection of biological hazards has been largely dependent on immunological agents (ie antibodies). Antibodies are expensive to manufacture and experience cross-reactivity, instability with shorter shelf life. Our aim was to improve the screening process of Shiga-toxin producing Escherichia coli (STEC) strains in food and environmental matrices by developing a novel, inexpensive handheld bacteriophage-based amperometric biosensor that can directly detect live STEC cells.This biosensor development began …

Evaluating The Dissemination Of The Icook 4-H Program Using Outcome, Process, And Fidelity Measures., Tara Gould

Electronic Theses and Dissertations

The iCook 4-H Dissemination Study, conducted in five states, was a control-treatment design to test whether a newly developed program for obesity prevention for youth could be successfully implemented by community leaders with minimal researcher involvement. Community leaders were primarily Cooperative Extension educators. A dyad model was used for youth (control=9.6±0.9 years of age; treatment=9.9±0.6 years of age) and their adult main food preparers (control=38.8±5.7 years of age; treatment=39.4±7.8 years of age). A three-pronged approach to evaluation developed previously for the program was used to measure outcomes, process, and fidelity of the program. The control group, youth (n=63) and adults …

Investigating The Relationship Among Sleep, Stress, And Body Mass Index In At-Risk First-Year College Students, Grace A. Violette

Electronic Theses and Dissertations

The study objective was to investigate relationships among body mass index (BMI), sleep quality/duration, and perceived stress in 1,176 first semester college students who enrolled in Get Fruved, an 8-state social marketing intervention to prevent unwanted weight gain. Research was limited to first-year college students at-risk for unwanted weight gain. Eligibility was based on self-report of inadequate fruit and vegetable intake and subjects meeting one or more health-risk criteria (e.g., high BMI). Students (mean age=181 years; 65% white) completed physical measurements and an online survey, including the Pittsburgh Sleep Quality Index (PSQI) (score range 0-21; ˃5=disordered sleep) and the Cohen …

Preparing For Effective Program Dissemination And Implementation: An Analysis Of Problems And Proposals For The Icook 4-H Program, Jodi L. Randall

Electronic Theses and Dissertations

While much effort has gone into the creation of obesity prevention programs like iCook 4-H, such programs remain largely under-utilized. The disconnect between research and practice highlights the necessity of dissemination and implementation strategies to ensure programs become adopted into practice. Creating a well-informed systematic approach to implementation will ensure that the iCook 4-H program will be implemented efficaciously and sustainably to improve the health of generations to come. The goal of this research was to implement the pilot dissemination and describe the findings in the context of the Quality Implementation Framework. The objectives were to report outcomes of the …

Eating For Environmental And Personal Health: Green Eating, Health Behavior And Environmental Perceptions At The University Of Maine, Moira E. Burke

Electronic Theses and Dissertations

The purpose of this study was to determine if green eating (GE), defined as environmentally conscious eating, in college students had an impact on BMI, health behavior, fruit and vegetable intake, physical activity, and perceptions of the campus environment. This was a cross-sectional study of undergraduate and graduate students (n=190) at the University of Maine. The GE Survey was used to determine GE stage of change; participants were classified as either pre-action (precontemplation, contemplation, preparation) (n=113) or post-action (action, maintenance) (n=77). The GE Survey was also used to assess GE behavior, decisional balance, and self-efficacy. A de novo health behavior …

Improving Extraction Of Allergenic Soy Proteins From Soy Products, Amma Konadu Amponsah

Electronic Theses and Dissertations

With recent increase in the utilization of soy proteins, there are mounting concerns of the escalation of soy allergies. It is, therefore, important to improve current methods of allergen detection to ensure accurate labeling of foods, produce more reliable and representative results in studies to create hypoallergenic food and establish allergen thresholds. The conditions used to extract proteins from foods are important determinants for appropriate detection and interpretation of the allergenicity of food materials. The extraction of soy proteins for soy allergen detections is conventionally performed with phosphate buffered saline (PBS) buffer for an extraction period of at least 2 …

Development Of A 3-Pronged Approach To Evaluation For The Icook-4h Project, Douglas R. Mathews

Electronic Theses and Dissertations

Most nutrition education programs are created without adequate forethought to planning evaluation strategies. The goal of this study was to develop and implement a comprehensive 3-pronged approach to evaluate iCook 4-H, a six- session, biweekly program for 9-10 year old youth and their adult main food preparer. It was used to evaluate the curriculum for the intervention of a 2-year childhood obesity prevention study. Forty iCook 4-H classes were implemented for 150 dyads by 16 leaders between September and December, 2013, in Maine, Nebraska, South Dakota, Tennessee, and West Virginia. The evaluation included measures of fidelity of implementation, process evaluation, …

Method Development For Vitamin C Quantification In Two Complex Matrices, Hannah D. Hutt

Electronic Theses and Dissertations

The following liquid chromatographic (LC) method developments and applied research studies were done using two complex food matrices, potatoes and elderberries, which are common to the state of Maine. Potatoes are Maine’s largest agricultural crop, a staple food in most U.S. households, and are, from an analytical standpoint, considered a complex matrix due to the high starch content that can be difficult to remove without degrading or removing nutrients in the process. Elderberries are an emerging crop in the U.S. because of their antioxidant and anti-viral properties and are found growing wild, throughout Maine. Elderberries are also considered a complex …

The Effect Of Wild Blueberry Consumption On The Inflammatory Response, Oxidative Stress And Dna Damage Associated With Exercise, Taylor K. Bloedon

Electronic Theses and Dissertations

At all levels of intensity and duration, exercise is known to cause an increase in the generation of reactive oxygen species (ROS). When derivatives of oxygen occur and exist independently with one or more unpaired electrons they are known as “free radicals” (Halliwell and Gutteridge 2007). Since atoms possess electrons that are usually associated in pairs, free radicals have the potential to act negatively in the body. Reactive oxygen species refer to oxygen-centered radicals as well as nonradical but reactive derivatives of oxygen (Halliwell and Gutteridge 2007). When ROS are created in excess, resulting in the disruption of the pro-oxidant/antioxidant …

Serum 25-Hydroxyvitamin D Response To Daily Oral Supplementation With 800 Iu Cholecalciferol In Premenopausal Women Living In Maine, Monica Nelson

Electronic Theses and Dissertations

The purpose of this research was to measure the serum 25-hydroxyvitamin D [25(OH)D] response to daily supplementation with 800 IU vitamin D3 during winter in premenopausal women living in Maine, and to examine the effects of body composition and hormonal contraceptive use on baseline serum 25(OH)D levels and the response to supplementation. One hundred twelve women (22.2±3.7 years old) received placebo from March 2005 until September 2005 when they were randomized to receive either placebo or 800 IU vitamin D3 through February 2006. Eighty-six women completed the study. Body composition was measured by dual-energy x-ray absorptiometry. Actual vitamin D3 content …

Dietary Patterns Of Mediterranean Adolescents, Sandra Ellan Brussee

Electronic Theses and Dissertations

The Mediterranean Diet (MD) is renowned for its health benefits. However, adherence appears to be lessening in the Mediterranean region as rates of overweight, obesity, and chronic disease are increasing. The adoption of a "western diet" (high amounts of meats, refined grains, snacks, and fast-food products) has been termed the "Nutrition Transition". Adolescents appear to be the most affected; therefore their diets and eating patterns were examined in this study. The objectives were to study food group-based consumption of adolescents, compare average servings with recommendations from the USDA Food Guide Pyramid (FGP) and the MD Pyramid, identify and compare eating …

The Effect Of Dietary Manganese On Arterial Functional Properties, Anastasia Z. Kalea

Electronic Theses and Dissertations

Dietary manganese affects the structure and integrity of blood vessels, as well as vessel predisposition to endothelial dysfunction and cardiovascular disease. In this thesis, we studied the role of manganese on the functional properties of rat aorta as defined by the endothelial and vascular smooth muscle cell pathways for adrenergic-mediated vasoconstriction and cholinergic-mediated vasodilation. Weanling Sprague-Dawley rats were fed a manganese deficient (MnD), adequate (MnA-control group) or supplemented (MnS) diet (<1, 10-15 and 45-50ppm Mn respectively). After 14 weeks on the diet the aorta was excised and four aortic rings of three mm length were prepared from each animal. Alterations in vasoconstriction among diet groups were detected by dose-response curves to the ^-adrenergic agonist LPhenylephrine in endothelium-intact and endothelium-disrupted rings. Alterations in endothelium-dependent vasodilation among diet groups were determined by doseresponse curves to Acetylcholine. We studied the mechanism by which dietary manganese affects two different endothelium-dependent vasodilation pathways: the Larginine/ nitric oxide (NO) and the cyclooxygenase (COX) pathways. Inhibition of the enzymes for NO synthesis (NOS) with L-NMMA, and of prostanoids (COX I and II) with Mefenamic acid, determination of NOS expression, and in vitro addition of L-Arginine (substrate for NO formation) to vessel rings revealed the effect of manganese on the regulation of endothelium-mediated vasodilation and vasoconstriction. Dose-response curves to sodium nitroprusside provided data for the dietary effect on endotheliumindependent vasodilation. Supplementary dietary manganese increased adrenoreceptor-mediated vascular smooth muscle contraction, which was significantly reduced in the presence of functional endothelium. Absence of dietary manganese increased endothelial cell sensitivity to the (Xi-adrenergic vasoconstrictor agent. Manganese had a small effect on the cGMP-pathway for dilation of vascular smooth muscle but affected vasodilation primarily through an endothelium-mediated pathway, probably by preserving NO bioavailability. Inhibition of vasodilation in Mn deficiency appears to occur through an endothelium-derived vasoconstrictor, possibly thromboxane with a concomitant decrease in the synthesis of endothelium-mediated vasodilator prostanoids. Our results demonstrate that dietary manganese influences the contractile machinery of vascular smooth muscle cells and regulates the bioactivity of endothelium-mediated vasodilators to affect agonist-induced signaling pathways that participate in the regulation of vasomotor tone. This suggests possibilities for dietary intervention in blood pressure regulation.