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1.
Appetite ; 200: 107572, 2024 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-38908405

RESUMO

Animal agriculture is a leading contributor to greenhouse gas emissions and other harmful environmental impacts, which underscores the need to shift away from the consumption of animal-based products. One promising nudge intervention is making plant-based meals the default option, so we tested this approach at six different university events across four academic institutions for effecting sustainable dietary change. Event attendees pre-selected their meal on one of two randomly assigned RSVP forms: one with a plant-based default and one with a meal with meat default. The results from our randomized controlled trial showed that participants had a 43-percentage point greater probability of selecting the plant-based meal when it was indicated as the default option. This effect was similar across events and academic institutions, which indicates that this default intervention is generalizable and can be successfully implemented at university events. The combined effect of using plant-based defaults at these six events was an estimated reduction of 104,387 kg of CO2 emissions, 299.9 m2 of land use, 959.0 g of nitrogen use, and 259.5 g of phosphorus use, which represent roughly 45-46.2% reductions in harmful environmental impacts relative to the meals chosen when using a meat default. Given the significance and magnitude of these environmental benefits, our results support the widespread implementation of plant-based defaults for helping universities improve their sustainability.


Assuntos
Meio Ambiente , Humanos , Universidades , Masculino , Feminino , Adulto , Refeições , Adulto Jovem , Preferências Alimentares/psicologia , Carne , Comportamento de Escolha , Dieta Vegetariana , Efeito Estufa/prevenção & controle , Gases de Efeito Estufa
2.
Public Health Nutr ; 24(1): 75-83, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32515718

RESUMO

OBJECTIVE: To explore adherence to a plant-based diet from the perspective of goals- and motivations-based systems. DESIGN: A cross-sectional, survey-based study was conducted regarding eating patterns, goals and motivations for current eating habits. SETTING: Data were collected using an online survey platform, including the Goal Systems Assessment Battery (GSAB) and other survey tools. PARTICIPANTS: University students were recruited, including thirty-three students reporting successful maintenance of a plant-based diet (Adherents) and sixty-three students trying to adhere to a plant-based diet (Non-adherents). RESULTS: Using GSAB subscale scores, discriminant function analyses significantly differentiated adherents v. non-adherents, accounting for 49·0 % of between-group variance (χ2 (13) = 42·03, P < 0·000). It correctly classified 72·7 % of adherents and 88·9 % of non-adherents. Constructs including value, self-efficacy, planning/stimulus control and positive affect were significant and included in the discriminant function. Logistic regression results suggested that participants who successfully adhered to a plant-based diet were seventeen times more likely to report 'To manage or treat a medical condition' as motivation and almost seven times more likely to report 'To align with my ethical beliefs' as motivation compared with non-adherents. However, these participants were 94 % less likely to report 'To maintain and/or improve my health' as motivation compared with non-adherents. Controlling for motivations, hierarchical logistic regression showed that only planning as part of the GSAB self-regulatory system predicted adherence to a plant-based diet. CONCLUSIONS: Values-based approaches to plant-based diets, including consideration for ethical beliefs, self-efficacy and proper planning, may be key for successful maintenance of this diet long-term.


Assuntos
Dieta Vegetariana , Objetivos , Motivação , Estudos Transversais , Humanos , Estudantes , Universidades
3.
BMC Public Health ; 20(1): 1295, 2020 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-32847553

RESUMO

BACKGROUND: The purpose of this study was to examine whether extended use of a variety of screen-based devices, in addition to television, was associated with poor dietary habits and other health-related characteristics and behaviors among US adults. The recent phenomenon of binge-watching was also explored. METHODS: A survey to assess screen time across multiple devices, dietary habits, sleep duration and quality, perceived stress, self-rated health, physical activity, and body mass index, was administered to a sample of US adults using the Qualtrics platform and distributed via Amazon Mechanical Turk (MTurk). Participants were adults 18 years of age and older, English speakers, current US residents, and owners of a television and at least one other device with a screen. Three different screen time categories (heavy, moderate, and light) were created for total screen time, and separately for screen time by type of screen, based on distribution tertiles. Kruskal-Wallis tests were conducted to examine differences in dietary habits and health-related characteristics between screen time categories. RESULTS: Aggregate screen time across all devices totaled 17.5 h per day for heavy users. Heavy users reported the least healthful dietary patterns and the poorest health-related characteristics - including self-rated health - compared to moderate and light users. Moreover, unique dietary habits emerged when examining dietary patterns by type of screen separately, such that heavy users of TV and smartphone displayed the least healthful dietary patterns compared to heavy users of TV-connected devices, laptop, and tablet. Binge-watching was also significantly associated with less healthy dietary patterns, including frequency of fast-food consumption as well as eating family meals in front of a television, and perceived stress. CONCLUSIONS: The present study found that poorer dietary choices, as well as other negative health-related impacts, occurred more often as the viewing time of a variety of different screen-based devices increased in a sample of US adults. Future research is needed to better understand what factors among different screen-based devices might affect health behaviors and in turn health-related outcomes. Research is also required to better understand how binge-watching behavior contributes impacts health-related behaviors and characteristics.


Assuntos
Computadores de Mão/estatística & dados numéricos , Dieta/psicologia , Comportamentos Relacionados com a Saúde , Tempo de Tela , Televisão/estatística & dados numéricos , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estresse Psicológico/psicologia , Inquéritos e Questionários , Fatores de Tempo , Estados Unidos
4.
BMC Public Health ; 19(1): 1386, 2019 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-31660931

RESUMO

BACKGROUND: Screen time among adults represents a continuing and growing problem in relation to health behaviors and health outcomes. However, no instrument currently exists in the literature that quantifies the use of modern screen-based devices. The primary purpose of this study was to develop and assess the reliability of a new screen time questionnaire, an instrument designed to quantify use of multiple popular screen-based devices among the US population. METHODS: An 18-item screen-time questionnaire was created to quantify use of commonly used screen devices (e.g. television, smartphone, tablet) across different time points during the week (e.g. weekday, weeknight, weekend). Test-retest reliability was assessed through intra-class correlation coefficients (ICCs) and standard error of measurement (SEM). The questionnaire was delivered online using Qualtrics and administered through Amazon Mechanical Turk (MTurk). RESULTS: Eighty MTurk workers completed full study participation and were included in the final analyses. All items in the screen time questionnaire showed fair to excellent relative reliability (ICCs = 0.50-0.90; all < 0.000), except for the item inquiring about the use of smartphone during an average weekend day (ICC = 0.16, p = 0.069). The SEM values were large for all screen types across the different periods under study. CONCLUSIONS: Results from this study suggest this self-administered questionnaire may be used to successfully classify individuals into different categories of screen time use (e.g. high vs. low); however, it is likely that objective measures are needed to increase precision of screen time assessment.


Assuntos
Tempo de Tela , Inquéritos e Questionários , Adulto , Feminino , Humanos , Masculino , Reprodutibilidade dos Testes
5.
Public Health Nutr ; 18(6): 994-1000, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24956064

RESUMO

OBJECTIVE: To understand factors which enhance or detract from farmers' market shopper experiences to inform targeted interventions to increase farmers' market utilization, community-building and social marketing strategies. DESIGN: A consumer-intercept study using the Stanford Healthy Neighborhood Discovery Tool to capture real-time perceptions via photographs and audio narratives. SETTING: An urban farmers' market in a large metropolitan US city. PARTICIPANTS: Thirty-eight farmers' market shoppers, who recorded 748 unique coded elements through community-based participatory research methods. RESULTS: Shoppers were primarily women (65 %), 18-35 years of age (54 %), non-Hispanic (81 %) and white (73 %). Shoppers captured 291 photographs (7·9 (sd 6·3) per shopper), 171 audio narratives (5·3 (sd 4·7) per shopper), and ninety-one linked photograph + audio narrative pairs (3·8 (sd 2·8) per shopper). A systematic content analysis of the photographs and audio narratives was conducted by eight independent coders. In total, nine common elements emerged from the data that enhanced the farmers' market experience (61·8 %), detracted from the experience (5·7 %) or were neutral (32·4 %). The most frequently noted elements were freshness/abundance of produce (23·3 %), product presentation (12·8 %), social interactions (12·4 %) and farmers' market attractions (e.g. live entertainment, dining offerings; 10·3 %). CONCLUSIONS: While produce quality (i.e. freshness/abundance) was of primary importance, other contextual factors also appeared important to the shoppers' experiences. These results may inform social marketing strategies to increase farmers' market utilization and community-building efforts that target market venues.


Assuntos
Comportamento do Consumidor , Abastecimento de Alimentos , Características de Residência , Adolescente , Adulto , Atitude Frente a Saúde , California , Pesquisa Participativa Baseada na Comunidade , Computadores de Mão , Feminino , Qualidade dos Alimentos , Abastecimento de Alimentos/economia , Frutas/química , Frutas/economia , Humanos , Relações Interpessoais , Masculino , Aplicativos Móveis , Pesquisa Qualitativa , População Urbana , Verduras/química , Verduras/economia , Adulto Jovem
6.
Ecol Food Nutr ; 54(3): 280-301, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25706248

RESUMO

Local foods programs such as community supported agriculture programs (CSAs) and farmers' markets have increased greatly in popularity. However, little research has been conducted regarding the effect of involvement in local foods programs on diet-related attitudes and behaviors. A series of focus groups was conducted to identify the motives that propel individuals to join a CSA, the experiences of belonging to a CSA, and the diet-related outcomes of CSA membership. Using the Theory of Planned Behavior (TPB) as a framework to categorize findings, data suggest the potential of CSAs as a viable intervention strategy for promoting healthful diets and behaviors.


Assuntos
Agricultura , Dieta , Comportamento Alimentar , Abastecimento de Alimentos , Comportamentos Relacionados com a Saúde , Motivação , Características de Residência , Adulto , Atitude Frente a Saúde , Comércio , Feminino , Grupos Focais , Promoção da Saúde , Humanos , Masculino , Teoria Psicológica
7.
J Diet Suppl ; : 1-17, 2024 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-38230707

RESUMO

The use of nutritional supplements can lead to doping risk and no data exist on high school athletes' use of certified third-party tested supplements. A cross-sectional cohort design was developed using an anonymous survey. Descriptive data for supplement use, use of third-party tested supplements, and knowledge in high school athletes were reported. A total of 225 high school athletes, ranging from 14-19 years of age, from a private high school in the western US, were included in the analysis of the results. A total of 94% (n=211) of athletes reported nutritional supplement use within the past year with an average of six (interquartile range: 3-9) individual supplements, ranging from 0-20 supplements per person. Most frequently reported were sports drinks (72%), vitamins (65%), sports bars (60%), protein powder (58%), caffeine (37%, as part of normal beverages, or 13% as a supplement), followed by creatine (23%). A total of 24% claimed to know for sure that all their supplements were third-party tested. In addition, the recognition of third-party testing organization icons was low (46% in supplement users vs. 14% in nonusers). Athletes also scored low in reporting how to find (22%) and how to order (25%) third-party tested supplements. In conclusion, almost all athletes in this study reported the use of multiple nutritional supplements annually. Only one-fourth of the athletes reported consistently using third-party tested supplements. Knowledge of where and how tested supplements could be purchased was limited in this high school athlete population.

8.
Artigo em Inglês | MEDLINE | ID: mdl-37510577

RESUMO

Food appreciation has been associated with favorable dietary and food waste behaviors. However, no validated food appreciation assessment currently exists. This study aimed to develop and validate a food appreciation scale (FAS) using data from two independent US-based samples recruited online. The 29-item FAS was based on existing literature regarding appreciation as a psychological construct, mindful eating, and epicurean tendencies. In Study 1, 311 participants completed the FAS, and exploratory factor analysis (EFA) was conducted. In Study 2, 300 participants completed the FAS, and confirmatory factor analysis (CFA) was conducted to determine whether the factor structure remained consistent. The EFA indicated a good model fit for a four-factor structure after excluding six items that loaded on multiple or no factors (TLI 0.95, CFI 0.97, SRMR 0.03, RMSEA 0.05), and Cronbach's alpha indicated excellent reliability (Cronbach's alpha values 0.82-0.9). The CFA confirmed the four-factor structure (TLI 0.97, CFI 0.98, SRMR 0.08, RMSEA 0.05) and acceptable factor loadings with a simple structure. The factors assessed active food appreciation, reflective food appreciation, mindful epicurean tendencies, and food-related rituals. The validated FAS could allow researchers to assess food appreciation, measure changes in food appreciation over time, and compare food appreciation among different study populations.


Assuntos
Alimentos , Eliminação de Resíduos , Humanos , Psicometria , Reprodutibilidade dos Testes , Inquéritos e Questionários , Análise Fatorial
9.
Am J Public Health ; 102(7): e53-5, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22594725

RESUMO

Although farmers' markets offer healthy foods for purchase, many lack the equipment necessary to process convenient, card-based transactions. We assessed the impact of providing wireless terminals to 5 markets on overall sales and redemption of Supplemental Nutrition Assistance Program (SNAP) benefits. Sales increased significantly at 4 of the 5 markets after implementation of the terminals, and overall sales increased above and beyond SNAP redemption alone. Implementation of wireless terminals may be important for improving the financial stability and accessibility of farmers' markets.


Assuntos
Terminais de Computador , Abastecimento de Alimentos , Marketing/instrumentação , Agricultura/organização & administração , Arizona , Promoção da Saúde/métodos , Humanos , Marketing/organização & administração , Projetos Piloto , Tecnologia sem Fio
10.
Photochem Photobiol Sci ; 11(3): 556-63, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22249211

RESUMO

The synthesis of photolabile tyrosine derivatives protected on the phenolic oxygen by the α-carboxy-6-nitroveratryl (αCNV) protecting group is described. The compounds undergo rapid photolysis at wavelengths longer than 300 nm to liberate the corresponding phenol in excellent yield (quantum yield for the deprotection of tyrosine = 0.19). Further protection of caged tyrosine is possible, yielding N-Fmoc protected derivatives suitable for direct incorporation of caged tyrosine in solid-phase peptide synthesis.


Assuntos
Nitrocompostos/química , Tirosina/química , Estrutura Molecular , Fotólise , Estereoisomerismo , Tirosina/análogos & derivados , Tirosina/síntese química
11.
Appetite ; 59(2): 431-6, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22698977

RESUMO

Community supported agriculture (CSA) programs have become a viable source of locally produced foods and represent a new way to increase fruit and vegetable consumption among individuals. Because CSAs represent a way for consumers to acquire healthy foods while providing financial support to local farmers, CSA involvement could reflect, and be related to, greater concern with both health and environmental impact of food choice. As such, the aim of this study was to examine whether ecological attitudes of CSA members could predict food- and sustainability-related behaviours. Using an online survey, respondents answered questions about attitudes towards the environment, as well behaviours related to food purchases, family food preparation, composting, recycling and minimising food-packaging waste. A total of 115 CSA member responses were collected. Ordinary least squares (OLS) multivariate regression analysis was used to investigate the predictive validity of environmental attitudes on measures of behaviours. A large portion of participants reported the amount and variety of fruits and vegetables their households ate increased as a result of joining a CSA program. Ecological sensitivity was a significant predictor of sustainability-related behaviours as well as money spent eating out and times eaten away from home per week. However, it was not predictive of family involvement in home food preparation.


Assuntos
Comportamento de Escolha , Comportamento Alimentar , Alimentos Orgânicos , Adulto , Agricultura , Arizona , Conservação dos Recursos Naturais , Inquéritos sobre Dietas , Meio Ambiente , Feminino , Frutas , Conhecimentos, Atitudes e Prática em Saúde , Hispânico ou Latino , Humanos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Projetos Piloto , Análise de Regressão , Inquéritos e Questionários , Verduras , População Branca
12.
PLoS One ; 17(10): e0275185, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36223342

RESUMO

BACKGROUND: Adverse Childhood Experiences (ACEs) include potentially traumatic exposures to neglect, abuse, and household problems involving substance abuse, mental illness, divorce, incarceration, and death. Past study findings suggest ACEs contribute to depression, while physical activity alleviates depression. Little is known about the link between ACEs and physical activity as it relates to depression among U.S. adults. This research had a primary objective of determining the role of physical activity within the link between ACEs and depression. The significance of this study involves examining physical activity as a form of behavioral medicine. METHODS: Data from the 2020 Behavioral Risk Factor Surveillance System were fit to Pearson chi-square and multivariable logistic regression models to examine the links between ACEs and depression, ACEs and physical activity, and physical activity and depression among U.S. adults ages 18-and-older (n = 117,204) from 21 states and the District of Columbia, while also determining whether physical activity attenuates the association between ACEs and depression. RESULTS: Findings from chi-square analyses indicated that ACEs are related to physical activity (χ2 = 19.4, df = 1; p<0.01) and depression (χ2 = 6,841.6, df = 1; p<0.0001). Regression findings suggest ACEs were linked to depression (AOR = 1.050; 95% CI = 1.049, 1.051). ACEs and physical activity (AOR = 0.994; 95% CI = 0.992, 0.995) and physical activity and depression (AOR = 0.927; 95% CI = 0.922, 0.932) were both inversely related. Physical activity mitigated the link between ACEs and depression (AOR = 0.995; 95% CI = 0.993, 0.996). CONCLUSIONS: This research addressed a critical knowledge gap concerning how ACEs and physical activity contribute to depression outcomes among U.S. adults. Findings suggest physical activity mitigates the effect of ACEs on depression. Future studies should apply physical activity interventions to alleviate depression among U.S. adults with high ACEs.


Assuntos
Experiências Adversas da Infância , Maus-Tratos Infantis , Adolescente , Adulto , Criança , Depressão/epidemiologia , Exercício Físico , Humanos
13.
J Biol Chem ; 285(20): 15440-15449, 2010 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-20200158

RESUMO

The plasmid partition protein KorB has a dual role: it is essential for the correct segregation of the low copy number broad host range RK2 plasmid while also being an important regulator of transcription. KorB belongs to the ParB family of proteins, and partitioning in RK2 has been studied as a simplified model of bacterial chromosome segregation. Structural information on full-length ParB proteins is limited, mainly due to the inability to grow crystals suitable for diffraction studies. We show, using CD and NMR, that KorB has regions of significant intrinsic disorder and hence it adopts a multiplicity of conformations in solution. The biophysical data are consistent with bioinformatic predictions based on the amino acid sequence that the N-terminal region and also the region between the central DNA-binding domain and the C-terminal dimerization domain are intrinsically disordered. We have used small angle x-ray scattering data to determine the ensemble of solution conformations for KorB and selected deletion mutants, based on models of the known domain structures. This conformational range of KorB is likely to be biologically required for DNA partitioning and for binding to a diverse set of partner proteins.


Assuntos
Proteínas de Bactérias/química , Plasmídeos , Sequência de Aminoácidos , Dicroísmo Circular , Dados de Sequência Molecular , Ressonância Magnética Nuclear Biomolecular , Conformação Proteica , Homologia de Sequência de Aminoácidos
14.
Nutrients ; 13(6)2021 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-34205306

RESUMO

The COVID-19 pandemic resulted in substantial lifestyle changes. No US study has identified predictors of perceived dietary healthfulness changes during the pandemic period. This study included analyses of lifestyle and dietary healthfulness changes using 958 survey responses from US primary household food purchasers. Information was collected related to demographics, COVID-19-related household changes, and health-related habits before and during the pandemic. Binary logistic regression identified predictors of perceived increase in dietary healthfulness during the pandemic period. Overall, 59.8%, 16.4%, and 23.4% of participants reported that their eating habits likely changed, may have changed, and likely did not change, respectively. Of the participants whose dietary habits likely or may have changed, 64.1%, 16.8%, and 19% reported healthier, neither healthier nor less healthy, and less healthy eating habits, respectively. COVID-19-related income loss, more meals consumed with household members in front of the television, an increase in food advertisement exposure, increased perceived stress, and better perceived current health were significant predictors of a perceived increase in dietary healthfulness. Overall, dietary habits were perceived to become healthier during the pandemic. The predictors of perceived improvement in dietary healthfulness were surprising and indicate the need for further study of these factors in crisis and noncrisis situations.


Assuntos
COVID-19 , Dieta , Comportamento Alimentar , Comportamentos Relacionados com a Saúde , Estilo de Vida , Pandemias , Adolescente , Adulto , Idoso , Feminino , Nível de Saúde , Humanos , Renda , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , SARS-CoV-2 , Estresse Psicológico , Inquéritos e Questionários , Televisão , Estados Unidos , Adulto Jovem
15.
Artigo em Inglês | MEDLINE | ID: mdl-33513709

RESUMO

Food waste contributes to adverse environmental and economic outcomes, and substantial food waste occurs at the household level in the US. This study explored perceived household food waste changes during the COVID-19 pandemic and related factors. A total of 946 survey responses from primary household food purchasers were analyzed. Demographic, COVID-19-related household change, and household food waste data were collected in October 2020. Wilcoxon signed-rank was used to assess differences in perceived food waste. A hierarchical binomial logistic regression analysis was conducted to examine whether COVID-19-related lifestyle disruptions and food-related behavior changes increased the likelihood of household food waste. A binomial logistic regression was conducted to explore the contribution of different food groups to the likelihood of increased food waste. Perceived food waste, assessed as the estimated percent of food wasted, decreased significantly during the pandemic (z = -7.47, p < 0.001). Food stockpiling was identified as a predictor of increased overall food waste during the pandemic, and wasting fresh vegetables and frozen foods increased the odds of increased food waste. The results indicate the need to provide education and resources related to food stockpiling and the management of specific food groups during periods of disruption to reduce food waste.


Assuntos
COVID-19 , Alimentos , Resíduos de Alimentos , Pandemias , Estudos Transversais , Características da Família , Humanos , Estados Unidos
16.
J Org Chem ; 75(13): 4648-51, 2010 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-20536152

RESUMO

The synthesis of a new photolabile protecting group for carboxylic acids, alpha-carboxy-6-nitroveratryl (alphaCNV), is described. Bromide 3, prepared in four steps from 3,4-dimethoxyphenylacetic acid, was used to alkylate carboxylic acids under mild conditions in good yield. Palladium-catalyzed deallylation afforded the acids 4a-h, which underwent rapid and quantitative photolysis at wavelengths longer than 300 nm to liberate the carboxylic acid in good to quantitative yield. The rate of photolysis and quantum yield were determined to be 325 s(-1) and 0.17.


Assuntos
Ácidos Carboxílicos/química , Nitrocompostos/química , Nitrocompostos/síntese química , Catálise , Estrutura Molecular , Fotoquímica , Fotólise , Teoria Quântica , Espectrofotometria Ultravioleta
18.
Artigo em Inglês | MEDLINE | ID: mdl-32486007

RESUMO

There are conflicting reports regarding the efficacy of plant versus animal-derived protein to support muscle and strength development with resistance training. The purpose of this study was to determine whether soy and whey protein supplements matched for leucine would comparably support strength increases and muscle growth following 12 weeks of resistance training. Sixty-one untrained young men (n = 19) and women (n = 42) (18-35 year) enrolled in this study, and 48 completed the trial (17 men, 31 women). All participants engaged in supervised resistance training 3×/week and consumed 19 grams of whey protein isolate or 26 grams of soy protein isolate, both containing 2 g (grams) of leucine. Multi-level modeling indicated that total body mass (0.68 kg; 95% CI: 0.08, 1.29 kg; p < 0.001), lean body mass (1.54 kg; 95% CI: 0.94, 2.15 kg; p < 0.001), and peak torque of leg extensors (40.27 Nm; 95% CI: 28.98, 51.57 Nm, p < 0.001) and flexors (20.44 Nm; 95% CI: 12.10, 28.79 Nm; p < 0.001) increased in both groups. Vastus lateralis muscle thickness tended to increase, but this did not reach statistical significance (0.12 cm; 95% CI: -0.01, 0.26 cm; p = 0.08). No differences between groups were observed (p > 0.05). These data indicate that increases in lean mass and strength in untrained participants are comparable when strength training and supplementing with soy or whey matched for leucine.


Assuntos
Suplementos Nutricionais , Leucina , Força Muscular , Treinamento Resistido , Proteínas de Soja , Proteínas do Soro do Leite , Composição Corporal , Método Duplo-Cego , Feminino , Humanos , Masculino , Músculo Esquelético , Adulto Jovem
19.
J Am Chem Soc ; 131(2): 749-57, 2009 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-19105697

RESUMO

Acyl-enzyme complexes are intermediates in reactions catalyzed by many hydrolases and related enzymes which employ nucleophilic catalysis. However, most of the reported structural data on acyl-enzyme complexes has been acquired under noncatalytic conditions. Recent IR analyses have indicated that some acyl-enzyme complexes may be more flexible than most crystallographic analyses have implied. OAT2 is a member of the N-terminal nucleophile (Ntn) hydrolase enzyme superfamily and catalyzes the reversible transfer of an acetyl group between the alpha-amino groups of ornithine and glutamate in a mechanism proposed to involve an acyl-enzyme complex. We have carried out biophysical analyses on ornithine acetyl transferase (OAT2), both in solution and in the crystalline state. Mass spectrometric studies identified Thr-181 as the residue acetylated during OAT2 catalysis; (13)C NMR analyses implied the presence of an acyl-enzyme complex in solution. Crystallization of OAT2 in the presence of N-alpha-acetyl-L-glutamate led to a structure in which Thr-181 was acetylated; the carbonyl oxygen of the acyl-enzyme complex was located in an oxyanion hole and positioned to hydrogen bond with the backbone amide NH of Gly-112 and the alcohol of Thr-111. While the crystallographic analyses revealed only one structure, IR spectroscopy demonstrated the presence of two distinct acyl-enzyme complex structures with carbonyl stretching frequencies at 1691 and 1701 cm(-1). Modeling studies implied two possible acyl-enzyme complex structures, one of which correlates with that observed in the crystal structure and with the 1691 cm(-1) IR absorption. The second acyl-enzyme complex structure, which has only a single oxyanion hole hydrogen bond, is proposed to give rise to the 1701 cm(-1) IR absorption. The two acyl-enzyme complex structures can interconvert by movement of the Thr-111 side-chain alcohol hydrogen away from the oxyanion hole to hydrogen bond with the backbone carbonyl of the acylated residue, Thr-181. Overall, the results reveal that acyl-enzyme complex structures may be more dynamic than previously thought and support the use of a comprehensive biophysical and modeling approach in studying such intermediates.


Assuntos
Acetiltransferases/química , Acetiltransferases/metabolismo , Acilação , Catálise , Quimotripsina/química , Quimotripsina/metabolismo , Simulação por Computador , Cristalografia por Raios X , Glutamatos/química , Glutamatos/metabolismo , Modelos Químicos , Modelos Moleculares , Ressonância Magnética Nuclear Biomolecular , Fenilpropionatos/química , Fenilpropionatos/metabolismo , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Espectrofotometria Infravermelho
20.
Nutrients ; 11(12)2019 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-31835510

RESUMO

Vegetarian diets provide an abundance of nutrients when carefully planned. However, vegetarian diets may have lower protein quality compared to omnivorous diets, a reflection of less favorable amino acid profiles and bioavailability. Hence, the current recommended dietary allowance for protein may not be adequate for some vegetarian populations. The purpose of this study was to determine dietary protein quality using the DIAAS (Digestible Indispensable Amino Acid Score) method in vegetarian and omnivore endurance athletes. DIAAS scores reflect the true ileal digestibility of the indispensable amino acids that are present in food items, and these scores can be used to compute the available protein in diet plans. Thirty-eight omnivores and 22 vegetarians submitted seven-day food records that were analyzed for nutrient content, and DIAAS scores were computed by diet group. Average available protein (g) was compared along with participants' lean body mass and strength (quantified using the peak torque of leg extension). DIAAS scores and available protein were higher for omnivorous versus vegetarian athletes (+11% and +43%, respectively, p < 0.05). Omnivorous participants had significantly higher lean body mass than vegetarian participants (+14%), and significant correlations existed between available protein and strength (r = 0.314) and available protein and lean body mass (r = 0.541). Based upon available protein, as determined through the DIAAS, vegetarian athletes in this study would need to consume, on average, an additional 10 g protein daily to reach the recommended intake for protein (1.2 g/kg/d). An additional 22 g protein daily would be needed to achieve an intake of 1.4 g/kg/d, the upper end of the recommended intake range.


Assuntos
Aminoácidos/metabolismo , Atletas , Dieta Vegetariana , Proteínas Alimentares/administração & dosagem , Digestão , Adulto , Aminoácidos/análise , Composição Corporal/efeitos dos fármacos , Índice de Massa Corporal , Estudos Transversais , Dieta , Proteínas Alimentares/metabolismo , Feminino , Humanos , Íleo/metabolismo , Masculino , Pessoa de Meia-Idade , Força Muscular/efeitos dos fármacos , Estado Nutricional , Vegetarianos
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