RESUMO
The objective of this study is to evaluate the effects of a strictly essential amino acid (lysine or threonine; EAA) deficiency on energy metabolism in growing rats. Rats were fed for three weeks severely (15% and 25% of recommendation), moderately (40% and 60%), and adequate (75% and 100%) lysine or threonine-deficient diets. Food intake and body weight were measured daily and indirect calorimetry was performed the week three. At the end of the experimentation, body composition, gene expression, and biochemical analysis were performed. Lysine and threonine deficiency induced a lower body weight gain and an increase in relative food intake. Lysine or threonine deficiency induced liver FGF21 synthesis and plasma release. However, no changes in energy expenditure were observed for lysine deficiency, unlike threonine deficiency, which leads to a decrease in total and resting energy expenditure. Interestingly, threonine severe deficiency, but not lysine deficiency, increase orexigenic and decreases anorexigenic hypothalamic neuropeptides expression, which could explain the higher food intake. Our results show that the deficiency in one EAA, induces a decrease in body weight gain, despite an increased relative food intake, without any increase in energy expenditure despite an induction of FGF21.
Assuntos
Lisina , Treonina , Ratos , Animais , Peso Corporal , Aumento de Peso , Metabolismo Energético , Ingestão de Alimentos/fisiologiaRESUMO
The FAO of the UN convened an Expert Working Group meeting to provide recommendations related to protein quality evaluation of Follow-up Formula for Young Children (FUF-YC) and Ready-to-Use Therapeutic Foods (RUTFs). The protein and amino acid (AA) scoring patterns for the target age groups were defined and recommendations provided on the use of currently available protein and indispensable AA digestibility data. For FUF-YC, an age category of 1-2.9 y was identified, and a matching protein requirement of 0.86 g · kg-1 · d-1 with corresponding AA requirements were recommended. For RUTF, the protein requirement recommended was 2.82 g · kg-1 · d-1, to achieve a catch-up weight gain of 10 g · kg-1 · d-1 in children recovering from severe acute malnutrition. The AA requirements were factorially derived based on the adult protein requirement for maintenance and tissue AA composition. A flowchart was proposed for the best available methods to estimate digestibility coefficients (of either protein or AAs), in the following order: human, growing pig, and rat true ileal AA digestibility values. Where this is not possible, fecal protein digestibility values should be used. The Expert Working Group recommends the use of the Protein Digestibility Corrected Amino Acid Score (PDCAAS), with existing protein digestibility values, or the Digestible Indispensable Amino Acid Score provided that individual AA digestibility values are available for protein quality evaluation using the latter score. The Group also recommends the use of ileal digestibility of protein or of AAs for plant-based protein sources, recognizing the possible effects of antinutritional factors and impaired gut function. A PDCAAS score of ≥90% can be considered adequate for these formulations, whereas with a score <90%, the quantity of protein should be increased to meet the requirements. Regardless of the protein quality score, the ability of formulations to support growth in the target population should be evaluated. Future research recommendations are also proposed based on the knowledge gaps identified.
Assuntos
Proteínas Alimentares/normas , Alimento Funcional , Fórmulas Infantis , Animais , Pré-Escolar , Proteínas Alimentares/metabolismo , Digestão , História do Século XXI , Humanos , LactenteRESUMO
Low-protein diets most often induce increased energy intake in an attempt to increase protein intake to meet protein needs with a risk of accumulation as fat of the excess energy intake. In female adult BALB/c mice, a decrease in dietary casein from 20% to 6% and 3% increased energy intake and slightly increased adiposity, and this response was exacerbated with soy proteins with low methionine content. The effect on fat mass was however limited because total energy expenditure increased to the same extent as energy intake. Lean body mass was preserved in all 6% fed mice and reduced only in 3% casein-fed animals. Insulin response to an oral glucose tolerance test was reduced in soy-fed mice and in low-protein-fed mice. Low-protein diets did not affect uncoupling protein 1 and increased fibroblast growth factor 21 (FGF21) in brown adipose tissue and increased FGF21, fatty acid synthase, and cluster of differentiation 36 in the liver. In the hypothalamus, neuropeptide Y was increased and proopiomelanocortin was decreased only in 3% casein-fed mice. In plasma, when protein was decreased, insulin-like growth factor-1 decreased and FGF21 increased and plasma FGF21 was best described by using a combination of dietary protein level, protein-to-carbohydrate ratio, and protein-to-methionine ratio in the diet. In conclusion, reducing dietary protein and protein quality increases energy intake but also energy expenditure resulting in an only slight increase in adiposity. In this process, FGF21 is probably an important signal that responds to a complex combination of protein restriction, protein quality, and carbohydrate content of the diet.
Assuntos
Adiposidade , Dieta com Restrição de Proteínas , Carboidratos da Dieta/administração & dosagem , Ingestão de Energia , Metabolismo Energético , Fatores de Crescimento de Fibroblastos/sangue , Fator de Crescimento Insulin-Like I/metabolismo , Metionina/deficiência , Valor Nutritivo , Amido/administração & dosagem , Tecido Adiposo/metabolismo , Ração Animal , Fenômenos Fisiológicos da Nutrição Animal , Animais , Biomarcadores , Carboidratos da Dieta/metabolismo , Regulação para Baixo , Feminino , Hipotálamo/metabolismo , Fígado/metabolismo , Camundongos Endogâmicos BALB C , Amido/metabolismo , Regulação para CimaRESUMO
Following a request from the European Commission, the EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) was asked to provide a supplementary dietary exposure and safety assessment of synthetic l-ergothioneine for those groups of the population which had been excluded by the applicant in the original application, i.e. infants and young children (i.e. toddlers), pregnant and breastfeeding women. Thus, intake estimates were calculated for these population groups and the following maximum anticipated daily intakes of l-ergothioneine from the NF, in addition to the background diet, were calculated: 2.82 mg/kg body weight (bw) per day for infants, 3.39 mg/kg bw per day for toddlers and 1.31 mg/kg bw per day for adults including pregnant and breastfeeding women. The Panel considers that based on the overall toxicological data the no-observed-adverse-effect level (NOAEL) of 800 mg/kg bw per day as established in the original assessment also pertains to pregnant and breastfeeding women as well as to young children (i.e. toddlers) and infants. The corresponding margins of exposure (i.e. the ratio between the NOAEL and the maximum anticipated daily intakes) are 284 for infants, 236 for young children and 610 for pregnant and breastfeeding women. These margins of exposure are considered sufficient. The Panel concludes that the novel food, synthetic l-ergothioneine, is safe under the proposed uses and use levels for infants, young children (i.e. toddlers) and pregnant and breastfeeding women.
RESUMO
The Protein Digestibility Corrected Amino Acid Score (PDCAAS) has been adopted for assessing protein quality in human foods since 1991, and the shortcomings of using the PDCAAS have been recognized since its adoption. The 2011 FAO Expert Consultation recognized that the Digestible Indispensable Amino Acid Score (DIAAS) was superior to the PDCAAS for determining protein quality. However, there were insufficient human data on amino acid digestibility before adopting the DIAAS. More human data were needed before DIAAS could be implemented. In 2014, FAO convened an expert working group to propose and agree on research protocols using both human-based assays and animal models to study ileal amino acid digestibility (metabolic availability) of human foods. The working group identified 5 research protocols for further research and development. A robust database of protein digestibility of foods commonly consumed worldwide, including those consumed in low-income countries, is needed for an informed decision on adopting the DIAAS. A review on the impacts of using the DIAAS on public health policies is necessary. It would be advantageous to have a global coordinating effort to advance research and data collection. Collaboration with international and national agriculture institutes is desirable. Opportunities should be provided for young researchers, particularly those from developing countries, to engage in protein-quality research for sustainable implementation of DIAAS. To conclude, the DIAAS is a conceptually preferable method compared with the PDCAAS for protein and amino acid quality evaluation. However, the complete value of the DIAAS and its impact on public health nutrition cannot be realized until there are sufficient accumulated ileal amino acid digestibility data on human foods that are consumed in different nutritional and environmental conditions, measured by competent authorities. A future meeting may be needed to evaluate the size and quality of the data set and to determine the timeline for full adoption and implementation of the DIAAS.
Assuntos
Aminoácidos/metabolismo , Bases de Dados Factuais , Dieta/normas , Proteínas Alimentares/normas , Digestão , Íleo/metabolismo , Projetos de Pesquisa , Animais , Disponibilidade Biológica , Países em Desenvolvimento , Proteínas Alimentares/metabolismo , Necessidades e Demandas de Serviços de Saúde , Humanos , Cooperação Internacional , Nações UnidasRESUMO
Obesity-prone (OP) rodents are used as models of human obesity predisposition. The goal of the present study was to identify preexisting defects in energy expenditure components in OP rats. Two studies were performed. In the first one, male Wistar rats (n = 48) were fed a high-carbohydrate diet (HCD) for 3 wk and then a high-fat diet (HFD) for the next 3 wk. This study showed that adiposity gain under HCD was 2.9-fold larger in carbohydrate-sensitive (CS) than in carbohydrate-resistant (CR) rats, confirming the concept of "carbohydrate-sensitive" rats. Energy expenditure (EE), respiratory quotient (RQ), caloric intake (CI), and locomotor activity measured during HFD identified no differences in EE and RQ between fat-resistant (FR) and fat-sensitive (FS) rats, and indicated that obesity developed in FS rats only as the result of a larger CI not fully compensated by a parallel increase in EE. A specific pattern of spontaneous activity, characterized by reduced activity burst intensity, was identified in FS rats but not in CS ones. This mirrors a previous observation that under HCD, CS but not FS rats, exhibited bursts of activity of reduced intensity. In a second study, rats were fed a HFD for 3 wk, and the components of energy expenditure were examined by indirect calorimetry in 10 FR and 10 FS rats. This study confirmed that a low basal EE, reduced thermic effect of feeding, defective postprandial energy partitioning, or a defective substrate utilization by the working muscle are not involved in the FS phenotype.
Assuntos
Carboidratos da Dieta/farmacologia , Gorduras na Dieta/farmacologia , Ingestão de Alimentos/efeitos dos fármacos , Metabolismo Energético/efeitos dos fármacos , Obesidade/genética , Obesidade/fisiopatologia , Animais , Composição Corporal/efeitos dos fármacos , Composição Corporal/fisiologia , Peso Corporal/efeitos dos fármacos , Peso Corporal/fisiologia , Calorimetria Indireta , Modelos Animais de Doenças , Ingestão de Alimentos/fisiologia , Metabolismo Energético/fisiologia , Predisposição Genética para Doença/genética , Locomoção/efeitos dos fármacos , Locomoção/fisiologia , Masculino , Ratos , Ratos WistarRESUMO
Dietary proteins are found in animal products, plant products and single-cell organisms. Proteins are present in variable proportions in these different food sources and the different proteins also differ in their amino acid composition, dietary indispensable amino acid content and physico-chemical properties. Different criteria can be used to define dietary protein requirements and different markers can be used to assess nutritional protein quality according to the criteria used for protein requirement estimation. The current approach to determining protein requirements is related to nitrogen balance and the dietary indispensable amino acid score approach relates protein quality to the capacity of protein to allow reaching nitrogen balance by providing nitrogen and indispensable amino acids. A second approach considers more directly protein nitrogen utilization by the body and includes measurement of protein digestibility and of the efficiency of dietary nitrogen retention at maintenance or for protein deposition at the whole body level or in more specific body areas. Another approach is related to protein turnover and protein synthesis in relation to maintenance and/or efficiency for deposition or development (growth) at the whole body level or for different and more specific target tissues such as muscle or bone. Lastly, protein quality can also be evaluated from different markers used as risk factors for metabolic dysfunction and disorders related for instance to insulin resistance, diabetes and obesity or cardio-vascular disease. The accuracy and relevance of these different approaches is discussed regarding the capacity of the different protein sources (i.e. animal as meat, milk or eggs, legume as soya or pea, or cereal as wheat or rice) to satisfy protein requirements according to these different criteria and markers.
Assuntos
Aminoácidos Essenciais/análise , Proteínas Alimentares/análise , Digestão , Doenças Metabólicas/metabolismo , Nitrogênio/metabolismo , Necessidades Nutricionais , Biossíntese de Proteínas , Animais , Biomarcadores , Dieta , Proteínas Alimentares/metabolismo , Crescimento/fisiologia , Humanos , Doenças Metabólicas/etiologia , Valor Nutritivo , Fatores de RiscoRESUMO
The aims of our study were to characterize the psychological dimensions of eating behaviour of young French adults as measured by the Three Factor Eating Questionnaire (TFEQ) and to analyze the association between the 3 TFEQ mean scores (main scales and subscales) and gender, Body Mass Index (BMI) and socio-demographic data in this population. An online TFEQ questionnaire was used with a nationally representative sample of 1000 young French people (aged 20-39yrs). The average scores were 6.3±0.1 (sem) for dietary restraint, 6.0±0.1 for disinhibition and 5.0±0.1 for hunger. Compared to the limit commonly used in human food studies, young French adults were characterized by low restraint and low disinhibition levels. There was a significant gender effect on both restraint and disinhibition scores, with women showing significantly higher scores than men. Concerning the link between TFEQ scores and BMI, there was a significant effect of the BMI category on cognitive restraint, disinhibition and hunger. Disinhibition was the factor most strongly associated to BMI, independently of gender. Our results highlight both the importance of taking into account not only disinhibition but also cognitive restraint and the usefulness of subscales when studying eating behaviour and its link to body weight. We characterize the eating behaviour of a French cohort with criteria often chosen for healthy volunteers in human food studies. Consequently, we suggest new TFEQ limits (6 for cognitive restraint and disinhibition, 5 for hunger) lower than those traditionally used for this category of the population in clinical food studies.
Assuntos
Comportamento Alimentar/psicologia , Inquéritos e Questionários , Adulto , Composição Corporal , Índice de Massa Corporal , Peso Corporal , Estudos de Coortes , Dieta , Dieta Redutora , Feminino , França , Humanos , Fome , Inibição Psicológica , Modelos Logísticos , Masculino , Fatores Socioeconômicos , População Branca , Adulto JovemRESUMO
High protein (HP) diet could serve as a good strategy against obesity, provoking the changes in energy metabolic pathways. However, those modifications differ during a dietary adaptation. To better understand the mechanisms involved in effect of high protein diet (HP) on limiting adiposity in rats we studied in parallel the gene expression of enzymes involved in protein and energy metabolism and the profiles of nutrients oxidation. Eighty male Wistar rats were fed a normal protein diet (NP, 14% of protein) for one week, then either maintained on NP diet or assigned to a HP diet (50% of protein) for 1, 3, 6 and 14 days. mRNA levels of genes involved in carbohydrate and lipid metabolism were measured in liver, adipose tissues, kidney and muscles by real time PCR. Energy expenditure (EE) and substrate oxidation were measured by indirect calorimetry. Liver glycogen and plasma glucose and hormones were assayed. In liver, HP feeding 1) decreased mRNA encoding glycolysis enzymes (GK, L-PK) and lipogenesis enzymes(ACC, FAS), 2) increased mRNA encoding gluconeogenesis enzymes (PEPCK), 3) first lowered, then restored mRNA encoding glycogen synthesis enzyme (GS), 4) did not change mRNA encoding ß-oxidation enzymes (CPT1, ACOX1, ßHAD). Few changes were seen in other organs. In parallel, indirect calorimetry confirmed that following HP feeding, glucose oxidation was reduced and fat oxidation was stable, except during the 1(st) day of adaptation where lipid oxidation was increased. Finally, this study showed that plasma insulin was lowered and hepatic glucose uptake was decreased. Taken together, these results demonstrate that following HP feeding, CHO utilization was increased above the increase in carbohydrate intake while lipogenesis was decreased thus giving a potential explanation for the fat lowering effect of HP diets.
Assuntos
Metabolismo dos Carboidratos/efeitos dos fármacos , Carboidratos da Dieta/farmacologia , Proteínas Alimentares/farmacologia , Glucose/metabolismo , Ração Animal , Animais , Metabolismo dos Carboidratos/fisiologia , Dieta com Restrição de Carboidratos/efeitos adversos , Metabolismo dos Lipídeos/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Modelos Biológicos , Oxirredução/efeitos dos fármacos , Ratos , Ratos Wistar , Regulação para CimaRESUMO
It has been suggested that high-protein (HP) diets may favor weight management by lowering energy intake and reducing body fat. Whether these effects result from changes in energy metabolism remains unclear. We measured the adaptation of energy metabolism components during 2 wk of HP feeding. Fifty male Wistar rats were switched from a control diet to an HP diet (14 and 55% of protein, respectively) for 1, 3, 6, or 14 d. Energy expenditure (EE) and substrate oxidation were measured by indirect calorimetry in feed-deprived rats and after consumption of a test meal. EE components, including the thermic effect of feeding and activity, were not modified during adaptation to an HP diet. Nutrient oxidation in feed-deprived rats was not affected by HP feeding, except for an early increase in protein oxidation. After 1 d, the postprandial inhibition of lipid oxidation (Lox) was blunted, carbohydrate (CHO) oxidation decreased by one-half, and urea clearance decreased by 66%. Thereafter, CHO oxidation gradually rose, resulting in a null CHO balance. Lox and urea clearance recovered after 3 d of adaptation to an HP diet, while protein oxidation reached a plateau. The postprandial oxidation of CHO counterbalanced the amount of ingested CHO as soon as 3 d, leading to a null postprandial CHO balance. We conclude that the inhibition of de novo lipogenesis from dietary CHO, but not EE and Lox, may participate in limiting the adiposity induced by HP feeding. The transient changes occurring during the period of adaptation to the diet highlight that the duration of the diet is critical in HP diet studies.
Assuntos
Adiposidade/fisiologia , Carboidratos da Dieta/metabolismo , Gorduras na Dieta/metabolismo , Proteínas Alimentares/metabolismo , Metabolismo Energético , Lipogênese/fisiologia , Obesidade/metabolismo , Animais , Regulação da Temperatura Corporal , Calorimetria Indireta , Carboidratos da Dieta/administração & dosagem , Gorduras na Dieta/administração & dosagem , Proteínas Alimentares/administração & dosagem , Masculino , Oxirredução , Período Pós-Prandial , Ratos , Ratos Wistar , Ureia/metabolismoRESUMO
Protein quality describes characteristics of a protein in relation to its ability to achieve defined metabolic actions. Traditionally, this has been discussed solely in the context of a protein's ability to provide specific patterns of amino acids to satisfy the demands for synthesis of protein as measured by animal growth or, in humans, nitrogen balance. As understanding of protein's actions expands beyond its role in maintaining body protein mass, the concept of protein quality must expand to incorporate these newly emerging actions of protein into the protein quality concept. New research reveals increasingly complex roles for protein and amino acids in regulation of body composition and bone health, gastrointestinal function and bacterial flora, glucose homeostasis, cell signaling, and satiety. The evidence available to date suggests that quality is important not only at the minimum Recommended Dietary Allowance level but also at higher intakes. Currently accepted methods for measuring protein quality do not consider the diverse roles of indispensable amino acids beyond the first limiting amino acid for growth or nitrogen balance. As research continues to evolve in assessing protein's role in optimal health at higher intakes, there is also need to continue to explore implications for protein quality assessment.
Assuntos
Proteínas Alimentares/administração & dosagem , Proteínas Alimentares/normas , Necessidades Nutricionais , Proteínas/metabolismo , Saciação/efeitos dos fármacos , Aminoácidos de Cadeia Ramificada/administração & dosagem , Aminoácidos de Cadeia Ramificada/metabolismo , Aminoácidos Essenciais/administração & dosagem , Aminoácidos Essenciais/metabolismo , Disponibilidade Biológica , Humanos , Política Nutricional , Valor Nutritivo , Controle de Qualidade , Saciação/fisiologiaRESUMO
We examined the effects of feeding conjugated linoleic acids (CLA) to adult male hamsters on several components of energy metabolism and body composition. Hamsters (n = 54) were assigned for 6-8 wk to one of three diets: 1) a standard diet (in percentage energy: lipids, 33, carbohydrates, 49, and proteins, 18); 2) to the standard diet augmented with the 9c,11t-isomer of CLA to 1.6% of energy (R group); or 3) the standard diet augmented with the 9c,11t-isomer and the 10t,12c-CLA isomer to 3.2 (1.6 + 1.6) % of energy (CLA mix group). (15)N uniformly labeled milk-protein was included in the diet to measure the incorporation of dietary protein into liver and muscle. Basal metabolic rate, thermogenic response to feeding and energy expenditure during spontaneous activity or during an exercise at approximately 60% of VO(2max) were measured. Carnitine palmitoyltransferase-I (CPT-I), leptin, insulin and triiodothyronine concentrations, as well as the in vivo overall adiposity changes were also determined. After 6 wk, the whole-body triglyceride content determined in vivo by NMR was significantly higher in the R group than in the control and CLA mix groups. The CLA mix group differed from the others in the lack of body triglyceride accumulation between d 21 and d 45 of the study, and the appearance of a slight insulin-resistance (homeostatic model assessment index, P < 0.05). Paradoxically, the lack of effect on whole-body lipid oxidation was associated with a greater CPT-I-specific activity in tissues of both CLA-fed groups (P < 0.05). No other major effects of CLA feeding were detected. In conclusion, CLA supplementation in hamsters did not affect adipose weight or the components of energy expenditure despite a theoretically higher capacity of red muscle to oxidize lipids. Only a CLA mixture prevented whole-body triglyceride accumulation over time.
Assuntos
Metabolismo Energético , Ácido Linoleico/administração & dosagem , Triglicerídeos/metabolismo , Animais , Composição Corporal/fisiologia , Calorimetria Indireta , Carnitina O-Palmitoiltransferase/metabolismo , Cricetinae , Metabolismo Energético/efeitos dos fármacos , Ácido Linoleico/química , Ácido Linoleico/farmacologia , Fígado/enzimologia , Fígado/metabolismo , Masculino , Mesocricetus , Músculo Esquelético/enzimologia , Músculo Esquelético/metabolismo , Nitrogênio/metabolismo , Isótopos de Nitrogênio , Condicionamento Físico Animal/fisiologiaRESUMO
BACKGROUND & AIMS: Irreversible amino acid losses at the human ileum are not taken into account when tracer-derived amino acid requirements are calculated because the data available are scarce. We have investigated amino acid losses at the ileal level in humans after ingestion of a protein meal. METHODS: Thirteen volunteers ingested a single meal of 15N milk or soy proteins. The appearance of 15N and 15N amino acids in the ileal effluents collected using an ileal tube was monitored for 8 hours. RESULTS: In the soy group, higher losses of endogenous nitrogen, especially originating from amino acids, were observed, as well as a higher flow rate of dietary non-amino acid nitrogen. With soy protein, the digestibilities of valine, threonine, histidine, tyrosine, alanine, and proline were significantly lower than with milk. Ileal losses of leucine, valine, and isoleucine amounted to 12, 10, and 7 mg x kg(-1) x day(-1), respectively. Threonine ileal loss (9-12 mg x kg(-1) x day(-1)) was particularly high compared with the current amino acid requirement. CONCLUSIONS: Amino acid losses at the human terminal ileum are substantial and depend on the type of dietary protein ingested. Although it remains unclear whether intact amino acids are absorbed in the colon, we suggest that ileal losses should be considered an important component of amino acid requirements.