Metabolismo energético, composição corporal e consumo alimentar na cirurgia bariátrica
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Data
2017-08-24
Autores
Ravelli, Michele Novaes [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Objetivo: verificar a influência do bypass gástrico em Y-de-Roux (BGYR) nas mudanças de composição corporal, gasto energético total (GET) e na acurácia das equações preditivas de GET, nos momentos pré e 6 e 12 meses após a cirurgia bariátrica. Métodos: Participaram da pesquisa 20 mulheres (IMC: 40 e 50 kg/m2; idade de 20 a 45 anos). As variáveis do estudo foram coletada nos momentos pré, 6 e 12 meses pós-cirurgia. O GET, massa livre de gordura (MLG) e massa gorda (MG) foram mensurados pela técnica da água duplamente marcada. O nível de atividade física (NAF) e o gasto de energia em atividade física (GEAF) foram obtidos por meio acelerômetro. O consumo energético foi obtido por três registros alimentares. Foram selecionadas as seguintes equações preditivas de gasto energético: Harris e Benedict (1819), World Health Organization (WHO-1985), Mifflin–St Jeor et al (1990), De Lorenzo et al (2001), por Müller et al (2004), Henry (Oxford - 2005), Dietary Reference Intake (DRI - 2005) e Lazzer et al (2007). Resultados: A perda ponderal (6 meses: -31 ± 4kg; 12 meses: -38 ± 6kg) teve contribuição de 17% e 16% da perda de MLG nos momentos 6 e 12 meses, respectivamente. O valor da razão MLG/MG passou de 0,93 ± 0,12kg do momento pré-cirurgia para 1,54 ± 0,4kg e 1,98 ± 0,6kg nos momentos 6 e 12 meses pós-operatórios (p<0,05). O GET reduziu 20% (-612 ± 317 kcal.dia-1) aos 6 meses -10% (-447 ± 516 kcal.dia-1) aos 12 meses de cirurgia, em relação ao valor pré-cirúrgico (p<0.05). Quando corrigido pela MLG, o GET/MLG não apresentou diferença significativa ao final do primeiro ano. A partir dos dados de GET mensurado em relação aos valores preditos por equação desenvolvida para estas pacientes, foi evidenciada a termogênese adaptativa (TA) aos 6 meses pós-operatórios em 39% das participantes, enquanto que aos 12 meses, uma melhor eficiência metabólica foi verificada em 50% das pacientes. A análise de regressão sugeriu que, aos 6 meses após a cirurgia, as mudanças GET se explicam pela alteração no GEAF (r2=0,60; p=0,00), porém, não houve associação com as alterações de composição corporal e IE (P>0,05). Aos 12 meses pós-cirurgia, foram destacadas as associações entre alterações do GET com as do peso corporal (r2=0,29; p=0,02), da MG (r2=0,28; p=0,02) e do GEAF (r2=0,49; p=0,00). Quanto à acurácia das fórmulas, as equações de Harris e Benedict (acurácia= 65%; viés= 0%) e DRI (acurácia= 60%; viés= 5%) apresentaram os melhores resultados na predição dos valores de GET, pré-cirurgia. No sexto mês pós-operatório, a maioria das equações apresentou redução na acurácia da predição. Apenas a equação de Harris e Benedict manteve a acurácia de predição do GET acima de 50%. Aos 12 meses pós-cirurgia, as equações que apresentavam baixa acurácia nos períodos anteriores, tiveram um aumento na predição, porém se mantiveram abaixo de 45% de acurácia. Apenas a equação proposta por Lazzer e col. considerando MLG e MG apresentou melhor predição (acurácia= 50%; viés= 9%) neste período. Conclusão: aos seis meses pós-operatórios evidenciou-se uma TA referente às restrições energéticas atribuídas pela cirurgia, no entanto, após um ano da cirurgia, uma maior eficiência metabólica foi associada ao GEAF, provavelmente pelo aumento da razão MLG/MG. Essas alterações do metabolismo energético, ocorridas ao longo de um ano do procedimento cirúrgico, podem explicar a grande variabilidade nos resultados das equações preditivas encontradas neste estudo.
Objective: To verify the influence of Roux-en-Y gastric bypass (RYGP) on changes in body composition (BC), total energy expenditure (TEE) and in the accuracy of the predictive equations of TEE, at the moments before and six and twelve months after bariatric surgery. Methods: Twenty women (BMI: 40 and 50 kg/m2; aged 20 to 45 years) participated in the study. The study variables were collected at pre, 6 and 12 months postoperatively. TEE, fat-free mass (FFM) and fat mass (FM) were measured by the doubly labeled water technique. The physical activity levels (PAL) and energy expenditure in physical activity (EEPA) were obtained through accelerometer. Energy intake (EI) was calculated using 3 days of dietary diaries. The following predictive energy expenditure equations were selected: Harris and Benedict (1819), World Health Organization (WHO-1985), Mifflin–St Jeor et al (1990), De Lorenzo et al (2001), Müller et al (2004), Henry (Oxford - 2005), Dietary Reference Intake (DRI - 2005), and Lazzer et al (2007). Results: The weight loss (6 months: -31 ± 4kg, 12 months: -38 ± 6kg) had a contribution of 17% and 16% of FFM loss at moments 6 and 12 months, respectively. The FFM/FM ratio increased from 0.93 ± 0.12kg from preoperative time to 1.54 ± 0.4kg and 1.98 ± 0.6kg at moments 6 and 12 postoperative months (p<0.05). The TEE reduced at 6 months 20% (-612 ± 317 kcal.dia-1) and -10% (-447 ± 516 kcal.dia-1) at 12months after surgery, in relation to the preoperative value (p <0.05). When corrected for lean mass, TEE/FFM showed no significant difference at the end of the first year. From the TEE data measured in relation to the predicted values by an equation developed for these patients, the adaptive thermogenesis was evidenced at 6 months postoperatively in 39% of the participants, whereas at 12 months, a better metabolic efficiency was verified in 50% of patients. Regression analysis suggested at six months after surgery, TEE changes are explained by EEPA change (r2= 0.60, p= 0.00), but there was no association with BC and EI changes (P> 0.05). Twelve months after surgery, the associations between TEE changes and those of body weight (r2= 0.29, p= 0.02), FM (r2= 0.28, p= 0.02) and EEPA (r2 = 0.49; p= 0.00) were highlighted. For accuracy of the formulas, the Harris and Benedict equations (accuracy= 65%; bias= 0%) and DRI (accuracy= 60%; bias= 5%) presented the best results in predicting TEE values at pre-surgery. In the sixth postoperative month, most of the equations presented a reduction in the accuracy of the TEE prediction. Only the Harris and Benedict equation maintained the prediction accuracy of TEE above 50%. At 12 months after surgery, the equations that presented low accuracy in previous periods had an increase in the prediction, but remained below 45% of accuracy. Only the equation proposed by Lazzer et al, considering FFM and FM showed better prediction (accuracy= 50%; bias= 9%) in this period. Conclusion: At six months postoperatively, there was an adaptive thermogenesis related to the energy restrictions attributed by the surgery, however, after one year of surgical treatment, a higher metabolic efficiency was associated with EEPA, probably due to the increase in the FFM/FM ratio. These energy metabolism changes, occurring within one year of the surgical procedure, may explain the great variability in the results of the predictive equations found in this study.
Objective: To verify the influence of Roux-en-Y gastric bypass (RYGP) on changes in body composition (BC), total energy expenditure (TEE) and in the accuracy of the predictive equations of TEE, at the moments before and six and twelve months after bariatric surgery. Methods: Twenty women (BMI: 40 and 50 kg/m2; aged 20 to 45 years) participated in the study. The study variables were collected at pre, 6 and 12 months postoperatively. TEE, fat-free mass (FFM) and fat mass (FM) were measured by the doubly labeled water technique. The physical activity levels (PAL) and energy expenditure in physical activity (EEPA) were obtained through accelerometer. Energy intake (EI) was calculated using 3 days of dietary diaries. The following predictive energy expenditure equations were selected: Harris and Benedict (1819), World Health Organization (WHO-1985), Mifflin–St Jeor et al (1990), De Lorenzo et al (2001), Müller et al (2004), Henry (Oxford - 2005), Dietary Reference Intake (DRI - 2005), and Lazzer et al (2007). Results: The weight loss (6 months: -31 ± 4kg, 12 months: -38 ± 6kg) had a contribution of 17% and 16% of FFM loss at moments 6 and 12 months, respectively. The FFM/FM ratio increased from 0.93 ± 0.12kg from preoperative time to 1.54 ± 0.4kg and 1.98 ± 0.6kg at moments 6 and 12 postoperative months (p<0.05). The TEE reduced at 6 months 20% (-612 ± 317 kcal.dia-1) and -10% (-447 ± 516 kcal.dia-1) at 12months after surgery, in relation to the preoperative value (p <0.05). When corrected for lean mass, TEE/FFM showed no significant difference at the end of the first year. From the TEE data measured in relation to the predicted values by an equation developed for these patients, the adaptive thermogenesis was evidenced at 6 months postoperatively in 39% of the participants, whereas at 12 months, a better metabolic efficiency was verified in 50% of patients. Regression analysis suggested at six months after surgery, TEE changes are explained by EEPA change (r2= 0.60, p= 0.00), but there was no association with BC and EI changes (P> 0.05). Twelve months after surgery, the associations between TEE changes and those of body weight (r2= 0.29, p= 0.02), FM (r2= 0.28, p= 0.02) and EEPA (r2 = 0.49; p= 0.00) were highlighted. For accuracy of the formulas, the Harris and Benedict equations (accuracy= 65%; bias= 0%) and DRI (accuracy= 60%; bias= 5%) presented the best results in predicting TEE values at pre-surgery. In the sixth postoperative month, most of the equations presented a reduction in the accuracy of the TEE prediction. Only the Harris and Benedict equation maintained the prediction accuracy of TEE above 50%. At 12 months after surgery, the equations that presented low accuracy in previous periods had an increase in the prediction, but remained below 45% of accuracy. Only the equation proposed by Lazzer et al, considering FFM and FM showed better prediction (accuracy= 50%; bias= 9%) in this period. Conclusion: At six months postoperatively, there was an adaptive thermogenesis related to the energy restrictions attributed by the surgery, however, after one year of surgical treatment, a higher metabolic efficiency was associated with EEPA, probably due to the increase in the FFM/FM ratio. These energy metabolism changes, occurring within one year of the surgical procedure, may explain the great variability in the results of the predictive equations found in this study.
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Palavras-chave
Obesidade, Cirurgia bariátrica, Metabolismo energético, Composição corporal, Obesity, Bariatric surgery, Energy metabolism, Body composition