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1.
Br J Nutr ; 100(2): 393-9, 2008 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-18205992

RESUMO

The effects of a 7 d high-fructose diet (HFrD) or control diet on lipid metabolism were studied in a group of six healthy lean males. Plasma NEFA and beta-hydroxybutyrate concentrations, net lipid oxidation (indirect calorimetry) and exogenous lipid oxidation (13CO2 production) were monitored in basal conditions, after lipid loading (olive oil labelled with [13C]triolein) and during a standardised mental stress. Lactate clearance and the metabolic effects of an exogenous lactate infusion were also monitored. The HFrD lowered plasma concentrations of NEFA and beta-hydroxybutyrate as well as lipid oxidation in both basal and after lipid-loading conditions. In addition, the HFrD blunted the increase in plasma NEFA and exogenous lipid oxidation during mental stress. The HFrD also increased basal lactate concentrations by 31.8 %, and lactate production by 53.8 %, while lactate clearance remained unchanged. Lactate infusion lowered plasma NEFA with the control diet, and net lipid oxidation with both the HFrD and control diet. These results indicate that a 7 d HFrD markedly inhibits lipolysis and lipid oxidation. The HFrD also increases lactate production, and the ensuing increased lactate utilisation may contribute to suppress lipid oxidation.


Assuntos
Dieta , Frutose/farmacologia , Metabolismo dos Lipídeos/efeitos dos fármacos , Estresse Psicológico/sangue , Ácido 3-Hidroxibutírico/sangue , Adulto , Metabolismo Basal/efeitos dos fármacos , Glicemia/metabolismo , Metabolismo Energético/efeitos dos fármacos , Ácidos Graxos não Esterificados/sangue , Frutose/administração & dosagem , Humanos , Ácido Láctico/sangue , Masculino , Fenômenos Fisiológicos da Nutrição
2.
Clin Nutr ; 26(2): 225-30, 2007 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-17270317

RESUMO

BACKGROUND AND AIMS: Fish oil (FO) supplementation prevents the development of obesity and insulin resistance, and upregulate the expression of UCP3 in skeletal muscle in rodents. This may represent indirect evidence that FO promotes fat oxidation and/or alter energy efficiency. The aim of this study was to evaluate whether such effects can be observed in humans. The metabolic effects of FO were assessed during exercise in order to obtain a direct measurement of energy efficiency. METHODS: Eight healthy male volunteers were studied with and without supplementation with 7.2 g/day FO (including 1.1 g/day eicosopentaenoic acid and 0.7 g/day decosahexaenoic acid) during 14 days. Their VO(2 max) was measured on cycle ergometer. Thereafter, energy metabolism (substrate oxidation, energy expenditure and energy efficiency) was assessed during a 30 min cycling exercise at 50% VO(2 max) performed 2 h 30 after a standardized, high carbohydrate breakfast. RESULTS: VO(2 max) was 38.6+/-2.2 after FO and 38.4+/-2.0 (mL x kg(-1) x min(-1)) in control conditions (NS). Basal plasma glucose, insulin and NEFA concentrations, and energy metabolism were similar with FO and in controls. During exercise, the increases in plasma NEFA concentrations, energy expenditure, glucose and lipid oxidation, and the decreases in glycaemia and insulinemia were not altered by FO intake. Energy efficiency was 22.4+/-0.6% after FO vs 21.8+/-0.7% in controls. In order to ascertain that the absence of effects of FO was not due to consumption of a carbohydrate meal immediately before exercise, 4 of the 8 subjects were re-studied in fasting conditions, FO also failed to alter energy efficiency in this subset of studies. CONCLUSION: FO supplementation did not significantly alter energy metabolism and energy efficiency during exercise in healthy humans.


Assuntos
Metabolismo Basal/efeitos dos fármacos , Glicemia/metabolismo , Metabolismo Energético/efeitos dos fármacos , Exercício Físico/fisiologia , Óleos de Peixe/administração & dosagem , Adulto , Metabolismo Basal/fisiologia , Ciclismo/fisiologia , Estudos Cross-Over , Suplementos Nutricionais , Metabolismo Energético/fisiologia , Ácidos Graxos não Esterificados/sangue , Humanos , Insulina/sangue , Peroxidação de Lipídeos/efeitos dos fármacos , Masculino , Oxirredução , Consumo de Oxigênio
3.
Nutrition ; 42: 75-81, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28870483

RESUMO

OBJECTIVE: In critically ill patients, acute injury alters gut function, causing greater risk for sepsis and malnutrition. Peptide-enriched diets may promote nitrogen absorption, whereas ω3-enriched diets reduce alterations in gut barrier function. The aim of this study was to assess the effectiveness of a peptide- and ω3-enriched diet on the metabolic response to injury and the gut barrier function in a model of prolonged catabolism in the rat. Given the intestinal trophic effect of glutamine, we tested for a synergistic effect of glutamine. METHODS: We randomized 40 male Sprague-Dawley rats (250 g) into four groups to enterally receive a standard high-protein diet (S), or a peptide- and ω3-enriched diet either alone (IMN) or supplemented with glutamine and alanine supplied as dipeptide (DIP) or as free amino acids (AAs) for 4 d. Metabolic response to injury was induced by turpentine injections on days 1 and 3. At sacrifice, nutritional and inflammatory biomarkers and intestinal and liver function were assessed. RESULTS: Weight gain (+45-62%) and nitrogen balance (+33-56%) were significantly higher in all groups than in the S group. In jejunal mucosa, total glutathione was significantly higher (+20-30%) and myeloperoxidase activity significantly lower in all groups compared with the S group. Hepatic triacylglycerol content was significantly lower in the AA (0.30 ± 0.04 µM/g) and DIP (0.43 ± 0.08 µM/g) groups than in the S group (0.71 ± 0.08 µM/g). CONCLUSIONS: In this model of prolonged catabolism, compared with a standard diet, a peptide- and ω3-enriched diet improved metabolic response to injury, with better nitrogen balance and weight recovery, and decreased intestinal myeloperoxidase activity. Only marginal additional effects of glutamine supplementation were observed with decreased hepatic fat content.


Assuntos
Dieta/métodos , Nutrição Enteral/métodos , Ácidos Graxos Ômega-3/farmacologia , Glutamina/farmacologia , Metabolismo/fisiologia , Ferimentos e Lesões/metabolismo , Doença Aguda , Animais , Modelos Animais de Doenças , Glutamina/administração & dosagem , Masculino , Nitrogênio/metabolismo , Ratos , Ratos Sprague-Dawley , Tempo , Aumento de Peso
4.
Clin Nutr ; 35(3): 669-78, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-26001619

RESUMO

BACKGROUND: Optimization of the refeeding strategy for the management of malnutrition in early life may enable to improve the quality of catch-up growth. While some data suggest better assimilation of peptides rather than whole proteins the evidence are scarce. OBJECTIVE: To compare the nutritional properties of peptides, partially hydrolyzed proteins or whole proteins in food-deprived/refed young rats. METHODS: Male SD rats (n = 109, 60-70 g) were food-deprived for 48 h and refed for 2-13 days. According to the set of experiments, refeeding was performed at 90% or 100% basal spontaneous intake or ad libitum with either peptide-, partially hydrolyzed protein- or whole protein-containing pediatric enteral nutrition formulas. Body weight, caloric intake and nitrogen balance were measured daily, intestinal trophicity was measured after two-day refeeding, and body composition was determined at the end of the refeeding period. RESULTS: A 2-day food deprivation in young rats led to significant body and organ weight losses, alterations of gut morphology, and decreased plasma citrulline, a marker of gut function. A cautious 2-day renutrition at 90% pre-deprivation level did not restore nutritional status whatever the form of nitrogen supply. Ad libitum feeding was shown to be feasible with improved nitrogen efficiency. After 13 days, compared to chow diet, body weight gain was the lowest with peptide- and whole protein-containing diets, and significantly improved with partially hydrolyzed proteins with limited improvement in body lean mass (+8%, NS). Additional experiments indicated that in this model it will be necessary to significantly increase nitrogen supply in order to restore initial body weight and lean body mass. CONCLUSIONS: Our results show benefits of ad libitum refeeding on catch-up growth. Our data suggest that partially hydrolyzed proteins may be beneficial in terms of body weight gain but that probably their effectiveness may be improved with higher nitrogen supply.


Assuntos
Proteínas Alimentares/uso terapêutico , Modelos Animais de Doenças , Alimentos Formulados , Mucosa Intestinal/patologia , Desnutrição/dietoterapia , Fragmentos de Peptídeos/uso terapêutico , Hidrolisados de Proteína/uso terapêutico , Animais , Biomarcadores/sangue , Citrulina/sangue , Proteínas Alimentares/efeitos adversos , Proteínas Alimentares/química , Digestão , Ingestão de Energia , Nutrição Enteral/efeitos adversos , Estudos de Viabilidade , Privação de Alimentos , Alimentos Formulados/efeitos adversos , Alimentos Formulados/análise , Absorção Intestinal , Mucosa Intestinal/metabolismo , Masculino , Desnutrição/sangue , Desnutrição/metabolismo , Desnutrição/patologia , Peso Molecular , Valor Nutritivo , Fragmentos de Peptídeos/efeitos adversos , Fragmentos de Peptídeos/química , Hidrolisados de Proteína/efeitos adversos , Hidrolisados de Proteína/química , Distribuição Aleatória , Ratos Sprague-Dawley , Aumento de Peso
6.
J Crohns Colitis ; 8(8): 825-34, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24462322

RESUMO

BACKGROUND: Anti-TNFα agents are commonly used for ulcerative colitis (UC) therapy in the event of non-response to conventional strategies or as colon-salvaging therapy. The objectives were to assess the appropriateness of biological therapies for UC patients and to study treatment discontinuation over time, according to appropriateness of treatment, as a measure of outcome. METHODS: We selected adult ulcerative colitis patients from the Swiss IBD cohort who had been treated with anti-TNFα agents. Appropriateness of the first-line anti-TNFα treatment was assessed using detailed criteria developed during the European Panel on the Appropriateness of Therapy for UC. Treatment discontinuation as an outcome was assessed for categories of appropriateness. RESULTS: Appropriateness of the first-line biological treatment was determined in 186 UC patients. For 64% of them, this treatment was considered appropriate. During follow-up, 37% of all patients discontinued biological treatment, 17% specifically because of failure. Time-to-failure of treatment was significantly different among patients on an appropriate biological treatment compared to those for whom the treatment was considered not appropriate (p=0.0007). Discontinuation rate after 2years was 26% compared to 54% between those two groups. Patients on inappropriate biological treatment were more likely to have severe disease, concomitant steroids and/or immunomodulators. They were also consistently more likely to suffer a failure of efficacy and to stop therapy during follow-up. CONCLUSION: Appropriateness of first-line anti-TNFα therapy results in a greater likelihood of continuing with the therapy. In situations where biological treatment is uncertain or inappropriate, physicians should consider other options instead of prescribing anti-TNFα agents.


Assuntos
Colite Ulcerativa/tratamento farmacológico , Fatores Imunológicos/uso terapêutico , Fator de Necrose Tumoral alfa/antagonistas & inibidores , Adolescente , Adulto , Idoso , Feminino , Humanos , Fatores Imunológicos/efeitos adversos , Prescrição Inadequada/estatística & dados numéricos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento , Adulto Jovem
7.
PLoS One ; 9(10): e109134, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25330088

RESUMO

BACKGROUND: Fat redistribution, increased inflammation and insulin resistance are prevalent in non-diabetic subjects treated with maintenance dialysis. The aim of this study was to test whether pioglitazone, a powerful insulin sensitizer, alters body fat distribution and adipokine secretion in these subjects and whether it is associated with improved insulin sensitivity. TRIAL DESIGN: This was a double blind cross-over study with 16 weeks of pioglitazone 45 mg vs placebo involving 12 subjects. METHODS: At the end of each phase, body composition (anthropometric measurements, dual energy X-ray absorptometry (DEXA), abdominal CT), hepatic and muscle insulin sensitivity (2-step hyperinsulinemic euglycemic clamp with 2H2-glucose) were measured and fasting blood adipokines and cardiometabolic risk markers were monitored. RESULTS: Four months treatment with pioglitazone had no effect on total body weight or total fat but decreased the visceral/sub-cutaneous adipose tissue ratio by 16% and decreased the leptin/adiponectin (L/A) ratio from 3.63 × 10(-3) to 0.76 × 10(-3). This was associated with a 20% increase in hepatic insulin sensitivity without changes in muscle insulin sensitivity, a 12% increase in HDL cholesterol and a 50% decrease in CRP. CONCLUSIONS/LIMITATIONS: Pioglitazone significantly changes the visceral-subcutaneous fat distribution and plasma L/A ratio in non diabetic subjects on maintenance dialysis. This was associated with improved hepatic insulin sensitivity and a reduction of cardio-metabolic risk markers. Whether these effects may improve the outcome of non diabetic end-stage renal disease subjects on maintenance dialysis still needs further evaluation. TRIAL REGISTRATION: ClinicalTrial.gov NCT01253928.


Assuntos
Adipocinas/sangue , Tecido Adiposo/efeitos dos fármacos , Resistência à Insulina , Falência Renal Crônica/metabolismo , Fígado/efeitos dos fármacos , Diálise Renal , Tiazolidinedionas/farmacologia , Tecido Adiposo/patologia , Adulto , Composição Corporal/efeitos dos fármacos , Estudos Cross-Over , Método Duplo-Cego , Jejum/sangue , Feminino , Glucose/metabolismo , Homeostase/efeitos dos fármacos , Humanos , Gordura Intra-Abdominal/efeitos dos fármacos , Gordura Intra-Abdominal/patologia , Falência Renal Crônica/sangue , Falência Renal Crônica/patologia , Falência Renal Crônica/terapia , Leptina/sangue , Fígado/metabolismo , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Pioglitazona , Gordura Subcutânea/efeitos dos fármacos , Gordura Subcutânea/patologia , Tiazolidinedionas/efeitos adversos
8.
Nutr Metab (Lond) ; 10(1): 4, 2013 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-23298392

RESUMO

BACKGROUND: PCSK9 (Proprotein Convertase Subtilisin Kexin type 9) is a circulating protein that promotes hypercholesterolemia by decreasing hepatic LDL receptor protein. Under non interventional conditions, its expression is driven by sterol response element binding protein 2 (SREBP2) and follows a diurnal rhythm synchronous with cholesterol synthesis. Plasma PCSK9 is associated to LDL-C and to a lesser extent plasma triglycerides and insulin resistance. We aimed to verify the effect on plasma PCSK9 concentrations of dietary interventions that affect these parameters. METHODS: We performed nutritional interventions in young healthy male volunteers and offspring of type 2 diabetic (OffT2D) patients that are more prone to develop insulin resistance, including: i) acute post-prandial hyperlipidemic challenge (n=10), ii) 4 days of high-fat (HF) or high-fat/high-protein (HFHP) (n=10), iii) 7 (HFruc1, n=16) or 6 (HFruc2, n=9) days of hypercaloric high-fructose diets. An acute oral fat load was also performed in two patients bearing the R104C-V114A loss-of-function (LOF) PCSK9 mutation. Plasma PCSK9 concentrations were measured by ELISA. For the HFruc1 study, intrahepatocellular (IHCL) and intramyocellular lipids were measured by 1H magnetic resonance spectroscopy. Hepatic and whole-body insulin sensitivity was assessed with a two-step hyperinsulinemic-euglycemic clamp (0.3 and 1.0 mU.kg-1.min-1). FINDINGS: HF and HFHP short-term diets, as well as an acute hyperlipidemic oral load, did not significantly change PCSK9 concentrations. In addition, post-prandial plasma triglyceride excursion was not altered in two carriers of PCSK9 LOF mutation compared with non carriers. In contrast, hypercaloric 7-day HFruc1 diet increased plasma PCSK9 concentrations by 28% (p=0.05) in healthy volunteers and by 34% (p=0.001) in OffT2D patients. In another independent study, 6-day HFruc2 diet increased plasma PCSK9 levels by 93% (p<0.0001) in young healthy male volunteers. Spearman's correlations revealed that plasma PCSK9 concentrations upon 7-day HFruc1 diet were positively associated with plasma triglycerides (r=0.54, p=0.01) and IHCL (r=0.56, p=0.001), and inversely correlated with hepatic (r=0.54, p=0.014) and whole-body (r=-0.59, p=0.0065) insulin sensitivity. CONCLUSIONS: Plasma PCSK9 concentrations vary minimally in response to a short term high-fat diet and they are not accompanied with changes in cholesterolemia upon high-fructose diet. Short-term high-fructose intake increased plasma PCSK9 levels, independent on cholesterol synthesis, suggesting a regulation independent of SREBP-2. Upon this diet, PCSK9 is associated with insulin resistance, hepatic steatosis and plasma triglycerides.

9.
Clin Nutr ; 31(2): 238-45, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22019201

RESUMO

BACKGROUND & AIMS: It has been reported that a high protein diet improves insulin sensitivity and reduces ectopic lipids in animals and humans with the metabolic syndrome. We therefore tested the hypothesis that a high dietary protein content may stimulate whole body lipid oxidation and alter post-prandial triglyceride (TG) after fructose ingestion. METHODS: The post-prandial metabolism of 8 young males was studied after two 6-day periods of hyper-energetic, high fructose diet (HiFruD), and after two 6-day periods of hyper-energetic high fructose high protein diet (HiFruHiProD). The order with which these periods were applied was randomized. At the end of each period, either a low protein, (13)C fructose test meal (Fru meal) or a high protein, (13)C fructose test meal (HiPro Fru meal) was administered. This resulted in the monitoring of metabolic parameters at 4 occasions in random order: a) with Fru meal ingested after HiFruD, b) with HiPro Fru meal ingested after HiFruD, c) with Fru meal ingested after HiFruHiProD or d) with HiPro Fru meal ingested after HiFruHiProD. On each occasion, post-prandial TG concentrations were monitored, energy expenditure and substrate metabolism were measured by indirect calorimetry, and fructose-induced gluconeogenesis was evaluated by measuring plasma (13)C-labeled glucose. RESULTS: TG responses to fructose ingestion were significantly higher after a hyper-energetic HiFruHiProD and after HiPro Fru meals than after a Fru meal ingested after a hyper-energetic HiFruD. Compared to low protein meals, high protein meals increased post-prandial energy expenditure, inhibited post-prandial lipid oxidation, and enhanced fructose-induced gluconeogenesis. These effects were similar with HiFruD and HiFruHiProD. CONCLUSIONS: Dietary proteins did not increase lipid oxidation and increased fructose-induced post-prandial TG in healthy humans fed an hyper-energetic, high fructose diet.


Assuntos
Dieta , Proteínas Alimentares/administração & dosagem , Frutose/administração & dosagem , Metabolismo dos Lipídeos/efeitos dos fármacos , Triglicerídeos/sangue , Glicemia/análise , Calorimetria Indireta , Estudos Cross-Over , Carboidratos da Dieta/administração & dosagem , Gorduras na Dieta/administração & dosagem , Metabolismo Energético , Ácidos Graxos não Esterificados/sangue , Frutose/metabolismo , Glucagon/sangue , Humanos , Insulina/sangue , Resistência à Insulina , Masculino , Período Pós-Prandial/efeitos dos fármacos , Adulto Jovem
10.
Clin Nutr ; 30(4): 494-8, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21288612

RESUMO

BACKGROUND & AIMS: High protein diets have been shown to improve hepatic steatosis in rodent models and in high-fat fed humans. We therefore evaluated the effects of a protein supplementation on intrahepatocellular lipids (IHCL), and fasting plasma triglycerides in obese non diabetic women. METHODS: Eleven obese women received a 60 g/day whey protein supplement (WPS) for 4-weeks, while otherwise nourished on a spontaneous diet, IHCL concentrations, visceral body fat, total liver volume (MR), fasting total-triglyceride and cholesterol concentrations, glucose tolerance (standard 75 g OGTT), insulin sensitivity (HOMA IS index), creatinine clearance, blood pressure and body composition (bio-impedance analysis) were assessed before and after 4-week WPS. RESULTS: IHCL were positively correlated with visceral fat and total liver volume at inclusion. WPS decreased significantly IHCL by 20.8 ± 7.7%, fasting total TG by 15 ± 6.9%, and total cholesterol by 7.3 ± 2.7%. WPS slightly increased fat free mass from 54.8 ± 2.2 kg to 56.7 ± 2.5 kg, p = 0.005). Visceral fat, total liver volume, glucose tolerance, creatinine clearance and insulin sensitivity were not changed. CONCLUSIONS: WPS improves hepatic steatosis and plasma lipid profiles in obese non diabetic patients, without adverse effects on glucose tolerance or creatinine clearance. TRIAL NUMBER: NCT00870077, ClinicalTrials.gov.


Assuntos
Colesterol/sangue , Proteínas do Leite/farmacologia , Obesidade/tratamento farmacológico , Triglicerídeos/sangue , Adulto , Aminoácidos/efeitos dos fármacos , Glicemia/análise , Pressão Sanguínea/efeitos dos fármacos , Composição Corporal/efeitos dos fármacos , Cromo , Creatinina/metabolismo , Dieta , Suplementos Nutricionais , Jejum , Fígado Gorduroso/tratamento farmacológico , Feminino , Teste de Tolerância a Glucose , Humanos , Insulina/sangue , Resistência à Insulina , Gordura Intra-Abdominal/metabolismo , Fígado/metabolismo , Ácidos Nicotínicos , Tamanho do Órgão , Proteínas do Soro do Leite
11.
Am J Clin Nutr ; 89(6): 1760-5, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19403641

RESUMO

BACKGROUND: Both nutritional and genetic factors are involved in the pathogenesis of nonalcoholic fatty liver disease and insulin resistance. OBJECTIVE: The aim was to assess the effects of fructose, a potent stimulator of hepatic de novo lipogenesis, on intrahepatocellular lipids (IHCLs) and insulin sensitivity in healthy offspring of patients with type 2 diabetes (OffT2D)--a subgroup of individuals prone to metabolic disorders. DESIGN: Sixteen male OffT2D and 8 control subjects were studied in a crossover design after either a 7-d isocaloric diet or a hypercaloric high-fructose diet (3.5 g x kg FFM(-1) x d(-1), +35% energy intake). Hepatic and whole-body insulin sensitivity were assessed with a 2-step hyperinsulinemic euglycemic clamp (0.3 and 1.0 mU x kg(-1) x min(-1)), together with 6,6-[2H2]glucose. IHCLs and intramyocellular lipids (IMCLs) were measured by 1H-magnetic resonance spectroscopy. RESULTS: The OffT2D group had significantly (P < 0.05) higher IHCLs (+94%), total triacylglycerols (+35%), and lower whole-body insulin sensitivity (-27%) than did the control group. The high-fructose diet significantly increased IHCLs (control: +76%; OffT2D: +79%), IMCLs (control: +47%; OffT2D: +24%), VLDL-triacylglycerols (control: +51%; OffT2D: +110%), and fasting hepatic glucose output (control: +4%; OffT2D: +5%). Furthermore, the effects of fructose on VLDL-triacylglycerols were higher in the OffT2D group (group x diet interaction: P < 0.05). CONCLUSIONS: A 7-d high-fructose diet increased ectopic lipid deposition in liver and muscle and fasting VLDL-triacylglycerols and decreased hepatic insulin sensitivity. Fructose-induced alterations in VLDL-triacylglycerols appeared to be of greater magnitude in the OffT2D group, which suggests that these individuals may be more prone to developing dyslipidemia when challenged by high fructose intakes. This trial was registered at clinicaltrials.gov as NCT00523562.


Assuntos
Diabetes Mellitus Tipo 2/metabolismo , Sacarose Alimentar/farmacologia , Dislipidemias/etiologia , Frutose/farmacologia , Metabolismo dos Lipídeos/efeitos dos fármacos , Fígado/efeitos dos fármacos , Músculo Esquelético/efeitos dos fármacos , Adulto , Estudos Cross-Over , Diabetes Mellitus Tipo 2/genética , Dislipidemias/genética , Dislipidemias/metabolismo , Predisposição Genética para Doença , Glucose/metabolismo , Humanos , Resistência à Insulina/genética , Metabolismo dos Lipídeos/genética , Lipoproteínas VLDL/sangue , Fígado/metabolismo , Masculino , Músculo Esquelético/metabolismo , Triglicerídeos/sangue , Adulto Jovem
12.
Am J Clin Nutr ; 90(4): 1002-10, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19710199

RESUMO

BACKGROUND: High sugar and fat intakes are known to increase intrahepatocellular lipids (IHCLs) and to cause insulin resistance. High protein intake may facilitate weight loss and improve glucose homeostasis in insulin-resistant patients, but its effects on IHCLs remain unknown. OBJECTIVE: The aim was to assess the effect of high protein intake on high-fat diet-induced IHCL accumulation and insulin sensitivity in healthy young men. DESIGN: Ten volunteers were studied in a crossover design after 4 d of either a hypercaloric high-fat (HF) diet; a hypercaloric high-fat, high-protein (HFHP) diet; or a control, isocaloric (control) diet. IHCLs were measured by (1)H-magnetic resonance spectroscopy, fasting metabolism was measured by indirect calorimetry, insulin sensitivity was measured by hyperinsulinemic-euglycemic clamp, and plasma concentrations were measured by enzyme-linked immunosorbent assay and gas chromatography-mass spectrometry; expression of key lipogenic genes was assessed in subcutaneous adipose tissue biopsy specimens. RESULTS: The HF diet increased IHCLs by 90 +/- 26% and plasma tissue-type plasminogen activator inhibitor-1 (tPAI-1) by 54 +/- 11% (P < 0.02 for both) and inhibited plasma free fatty acids by 26 +/- 11% and beta-hydroxybutyrate by 61 +/- 27% (P < 0.05 for both). The HFHP diet blunted the increase in IHCLs and normalized plasma beta-hydroxybutyrate and tPAI-1 concentrations. Insulin sensitivity was not altered, whereas the expression of sterol regulatory element-binding protein-1c and key lipogenic genes increased with the HF and HFHP diets (P < 0.02). Bile acid concentrations remained unchanged after the HF diet but increased by 50 +/- 24% after the HFHP diet (P = 0.14). CONCLUSIONS: Protein intake significantly blunts the effects of an HF diet on IHCLs and tPAI-1 through effects presumably exerted at the level of the liver. Protein-induced increases in bile acid concentrations may be involved. This trial was registered at www.clinicaltrials.gov as NCT00523562.


Assuntos
Proteínas Alimentares/farmacologia , Metabolismo dos Lipídeos , Fígado/metabolismo , Ácido 3-Hidroxibutírico/sangue , Adulto , Ácidos e Sais Biliares/sangue , Estudos Cross-Over , Gorduras na Dieta/farmacologia , Proteínas Alimentares/administração & dosagem , Ingestão de Energia , Ácidos Graxos não Esterificados/sangue , Humanos , Resistência à Insulina , Leptina/sangue , Metabolismo dos Lipídeos/genética , Masculino , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismo , Ativador de Plasminogênio Tecidual/sangue , Adulto Jovem
13.
Curr Opin Clin Nutr Metab Care ; 11(4): 477-82, 2008 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-18542010

RESUMO

PURPOSE OF REVIEW: The prevalence of nonalcoholic fatty liver disease is increasing worldwide and there is strong evidence that dietary factors play a role in its pathogenesis. The present review aims to provide a better understanding of how carbohydrates and other macronutrients may affect the disease. RECENT FINDINGS: The effects of carbohydrates on the development of nonalcoholic fatty liver disease differ depending upon the carbohydrate type; high-glycemic index foods are related to increased hepatic fat in both rodents and humans. Similarly, simple carbohydrates, such as fructose, stimulate hepatic de-novo lipogenesis and decrease lipid oxidation, thus leading to increased fat deposition. The underlying mechanisms may involve the activation of transcription factors. Fat intake broadly leads to hepatic fat deposition in rodents but few data are available on humans. Both carbohydrates and fat trigger inflammatory factors, which are closely related to metabolic disorders and nonalcoholic fatty liver disease. Lifestyle interventions appear to be the most appropriate first-line treatment for nonalcoholic fatty liver disease. SUMMARY: There is strong evidence that the diet may affect the development of nonalcoholic fatty liver disease. Although simple carbohydrates are clearly shown to have deleterious effects in humans, the role of fat remains controversial. Further studies will be required to evaluate the effects of macronutrient composition on the development of nonalcoholic fatty liver disease.


Assuntos
Carboidratos da Dieta/administração & dosagem , Gorduras na Dieta/administração & dosagem , Fígado Gorduroso/epidemiologia , Inflamação/fisiopatologia , Resistência à Insulina , Carboidratos da Dieta/efeitos adversos , Gorduras na Dieta/efeitos adversos , Fígado Gorduroso/etiologia , Fígado Gorduroso/fisiopatologia , Índice Glicêmico , Humanos
14.
Am J Clin Nutr ; 88(4): 877-85, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18842771

RESUMO

BACKGROUND: Dairy calcium supplementation has been proposed to increase fat oxidation and to inhibit lipogenesis. OBJECTIVE: We aimed to investigate the effects of calcium supplementation on markers of fat metabolism. DESIGN: In a placebo-controlled, crossover experiment, 10 overweight or obese subjects who were low calcium consumers received 800 mg dairy Ca/d for 5 wk. After 4 wk, adipose tissue was taken for biopsy for analysis of gene expression. Respiratory exchange, glycerol turnover, and subcutaneous adipose tissue microdialysis were performed for 7 h after consumption of 400 mg Ca or placebo, and the ingestion of either randomized slow-release caffeine (SRC; 300 mg) or lactose (500 mg). One week later, the test was repeated with the SRC or lactose crossover. RESULTS: Calcium supplementation increased urinary calcium excretion by 16% (P = 0.017) but did not alter plasma parathyroid hormone or osteocalcin concentrations. Resting energy expenditure (59.9 +/- 3.0 or 59.6 +/- 3.3 kcal/h), fat oxidation (58.4 +/- 2.5 or 53.8 +/- 2.2 mg/min), plasma free fatty acid concentrations (0.63 +/- 0.02 or 0.62 +/- 0.03 mmol/L), and glycerol turnover (3.63 +/- 0.41 or 3.70 +/- 0.38 micromol . kg(-1) . min(-1)) were similar with or without calcium, respectively. SRC significantly increased free fatty acid concentrations, resting fat oxidation, and resting energy expenditure. During microdialysis, epinephrine increased dialysate glycerol concentrations by 250% without and 254% with calcium. Expression of 7 key metabolic genes in subcutaneous adipose tissue was not affected by calcium supplementation. CONCLUSION: Dairy calcium supplementation in overweight subjects with habitually low calcium intakes failed to alter fat metabolism and energy expenditure under resting conditions and during acute stimulation by caffeine or epinephrine.


Assuntos
Tecido Adiposo/metabolismo , Cálcio da Dieta/administração & dosagem , Metabolismo dos Lipídeos/efeitos dos fármacos , Obesidade/metabolismo , Sobrepeso/metabolismo , Adulto , Metabolismo Basal , Biomarcadores/sangue , Biomarcadores/urina , Cafeína/farmacologia , Cálcio/urina , Estudos Cross-Over , Laticínios , Método Duplo-Cego , Metabolismo Energético/efeitos dos fármacos , Metabolismo Energético/fisiologia , Epinefrina/metabolismo , Ácidos Graxos não Esterificados/metabolismo , Feminino , Glicerol/metabolismo , Humanos , Lactose/farmacologia , Metabolismo dos Lipídeos/fisiologia , Masculino , Microdiálise , Osteocalcina/sangue , Oxirredução/efeitos dos fármacos , Consumo de Oxigênio , Hormônio Paratireóideo/sangue , RNA Mensageiro/metabolismo
15.
Diabetes Care ; 31(6): 1254-6, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18332156

RESUMO

OBJECTIVE: To compare the metabolic effects of fructose in healthy male and female subjects. RESEARCH DESIGN AND METHODS: Fasting metabolic profile and hepatic insulin sensitivity were assessed by means of a hyperglycemic clamp in 16 healthy young male and female subjects after a 6-day fructose overfeeding. RESULTS: Fructose overfeeding increased fasting triglyceride concentrations by 71 vs. 16% in male vs. female subjects, respectively (P < 0.05). Endogenous glucose production was increased by 12%, alanine aminotransferase concentration was increased by 38%, and fasting insulin concentrations were increased by 14% after fructose overfeeding in male subjects (all P < 0.05) but were not significantly altered in female subjects. Fasting plasma free fatty acids and lipid oxidation were inhibited by fructose in male but not in female subjects. CONCLUSIONS: Short-term fructose overfeeding produces hypertriglyceridemia and hepatic insulin resistance in men, but these effects are markedly blunted in healthy young women.


Assuntos
Frutose/farmacologia , Triglicerídeos/sangue , Adulto , Índice de Massa Corporal , Ingestão de Energia , Jejum , Feminino , Humanos , Insulina/sangue , Masculino , Valores de Referência , Caracteres Sexuais
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