RESUMO
BACKGROUND: Fatty liver is highly prevalent among obese children and represents a major risk factor for chronic liver diseases and severe metabolic complications. METHODS: We randomly assigned 17 obese children 8-17 years of age with fatty liver to either an experimental low-glycemic-load or conventional low-fat diet for 6 months. Participants in both groups received nutrition education and behavioral counseling of equal intensity. The primary outcome was hepatic lipid content measured by proton magnetic resonance spectroscopy. Secondary outcomes included change in visceral fat, BMI, anthropometrics, alanine aminotransferase (ALT), and insulin resistance. RESULTS: A total of 16 participants completed the study. Reported glycemic load decreased in the low-glycemic-load group and reported dietary fat decreased in the low-fat group. At baseline, liver fat was 23.8% [standard deviation (SD) 12.2] in the low-glycemic-load group and 29.3% (14.1) in the low-fat group. Liver fat decreased substantially in both groups at 6 months expressed as absolute percentage change, with no between-group differences [-8.8 (standard error (SE) 4.1) vs. -10.5 (3.7)%, respectively, p=0.76 for group×time interaction]. Secondary outcomes also improved on both diets, with no between-group differences. Baseline and change in ALT were strongly associated with hepatic fat content. CONCLUSIONS: Weight-reducing diets focused either on glycemic load or dietary fat improved hepatic steatosis over 6 months. Additional research is needed to determine whether these diets differ in effectiveness over the long term. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00480922.
Assuntos
Glicemia/metabolismo , Dieta com Restrição de Gorduras , Fígado Gorduroso/sangue , Resistência à Insulina , Lipídeos/sangue , Obesidade/sangue , Redução de Peso , Adiposidade , Adolescente , Alanina Transaminase , Criança , Dieta Redutora , Carboidratos da Dieta , Fígado Gorduroso/epidemiologia , Fígado Gorduroso/etiologia , Feminino , Índice Glicêmico , Humanos , Gordura Intra-Abdominal , Masculino , Massachusetts/epidemiologia , Obesidade/complicações , Obesidade/epidemiologia , Resultado do TratamentoAssuntos
Diabetes Mellitus Tipo 2/genética , Dieta , Carboidratos da Dieta/metabolismo , Regulação da Expressão Gênica , Índice Glicêmico , Diabetes Mellitus Tipo 2/metabolismo , Humanos , Síndrome Metabólica/genética , Síndrome Metabólica/metabolismo , Análise em Microsséries , Transdução de SinaisRESUMO
Exercise-induced growth hormone (GH) secretion may significantly modulate growth and development in children. Altered physiological GH responses, therefore, may reduce the beneficial effects of exercise. High-fat food ingestion before exercise blunts the GH response in adults, but it is unknown whether this occurs in children. We therefore performed standard exercise tests, following a high-fat meal or placebo, in 12 children, age 11-15 (6 M, 6 F). GH, insulin-like growth factor-I, glucose, insulin, glucagon, cortisol, epinephrine and interleukin-6 samples were drawn at baseline, end-exercise, and 30 and 60 min post-exercise. While GH was similar at baseline in all experiments, the exercise-induced GH peak was lower after the high-fat meal (6.7 +/- 1.6 ng/l vs 11.8 +/- 2.4 ng/l, p <0.02). Other exercise responses were not affected by prior fat ingestion. A high-fat meal before exercise, therefore (a common event in Western societies), may reduce the growth factor response to exercise in children, with potential implications for growth and development.
