Efeito da ingestão de mate solúvel (Ilex paraguariensis) em marcadores de estresse oxidativo, perfil glicêmico e composição corporal de adolescentes: ensaio clínico controlado e randomizado

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências da Saúde, Programa de Pós-Graduação em Nutrição, Florianópolis, 2016.A obesidade e o sobrepeso apresentam forte associação com o estresse oxidativo e com alterações no perfil glicêmico, aumentando o risco cardiometabólico, particularmente, em crianças e adolescentes. Neste contexto, estratégias terapêuticas dietéticas que possam prevenir ou minimizar as complicações da obesidade infanto-juvenil são recomendadas, inclusive, pelo uso da erva mate (Ilex paraguariensis), espécie vegetal rica em compostos antioxidantes e anti-inflamatórios, com propriedades hipoglicêmicas e antiobesidade. Assim, o objetivo do presente estudo foi verificar o efeito do consumo de mate tostado solúvel em adolescentes do munícipio de São José-SC em marcadores séricos de estresse oxidativo e do perfil glicêmico e nos indicadores da composição corporal. O efeito da ingestão de mate solúvel nas variáveis de consumo alimentar também foi avaliado. Participaram do estudo 76 estudantes (69,7% meninas), com idade entre 13 e 17 anos, randomizados em grupo controle (GC; n = 37) e grupo mate (GM; n = 39). Os participantes de cada grupo foram, ainda, estratificados pelo estado nutricional em eutróficos, com sobrepeso e obesos, de acordo com o índice de massa corporal (IMC) e escore-Z. Os estudantes do GC e GM foram orientados a ingerir, respectivamente, as doses de 0,1 e 1,0 g de mate solúvel em 200 mL de água, três vezes ao dia, durante 60 dias. No período basal e após 7, 30 e 60 dias, após jejum de 10-12 h, amostras de sangue foram coletadas para as medidas da capacidade antioxidante total (TAC), estado oxidante total (TOS), paroxonase-1 (PON-1), glicose e insulina. Os parâmetros antropométricos IMC, escore-Z e circunferência da cintura (CC) foram avaliados nos períodos basal, 30 e 60 dias, enquanto os percentuais de gordura corporal (%GC) e de massa magra corporal (MM) foram avaliados por bioimpedância no início e fim do estudo. Para detectar os efeitos do consumo do mate tostado, foram aplicados os testes ANOVA-RM e teste complementar de Tukey ou teste de Friedman e teste de Dunn, dependendo da distribuição dos dados. Diferenças entre o estado nutricional foram detectadas pela ANOVA e teste de Tukey ou Kruskal-Wallis e teste de Dunn. As comparações intergrupos foram realizadas por meio dos testes t de Student ou Mann-Whitney. As associações das variáveis foram determinadas pelo teste de correlação de Spearmam. Para todas as análises, pAbstract : Obesity and overweight are strongly associated with oxidative stress and with changes in the glycemic profile, increasing the cardiometabolic risk, particularly in children and adolescents. In this context, dietary therapeutic strategies that may prevent or minimize the complications of childhood obesity are recommended, including the use of the Yerb mate (Ilex paraguariensis), a plant species rich in antioxidant and anti-inflammatory compounds, with hypoglycemic and antiobesity properties. Therefore, the objective of the present study was to verify the effect of the consumption of soluble roasted mate in adolescents of the São José city, SC, on serum indicators of oxidative stress and glycemic profile and on body composition indicators. The effect of ingesting soluble mate on food consumption variables was also evaluated. A total of 76 students (69.7% girls), ages 13 to 17 y, were randomly assigned to a control group (CG; n = 37) and mate group (MG; n = 39). The participants of each group were also stratified by nutritional status in eutrophic, overweight and obese according to body mass index (BMI) and Z-score. CG and MG students were instructed to ingest doses of 0.1 and 1.0 g of soluble mate in 200 mL of water, respectively, three times a day for 60 days, respectively. During the beginning and after 7, 30 and 60 days, blood samples were collected after 10-12 h fasting, for the serum measurement of total antioxidant capacity (TAC), total oxidant status (TOS), paroxonase-1 (PON-1) activity, glucose and insulin. The anthropometric parameters BMI, Z-score and waist circumference (WC) were evaluated in the beginning and after 30 and 60 days, while the body fat (%BF) and body mass (BM) percentages were evaluated by bioimpedance in the beginning and at the end of study. In order to detect the effects of the soluble mate consumption, ANOVA-RM tests and Tukey complementary test or Friedman test and Dunn test were applied, depending on the distribution of data. Differences between nutritional status were detected by ANOVA and Tukey or Kruskal-Wallis test and Dunn's test. Intergroup comparisons were performed using the Student t or Mann-Whitney tests. The associations of the variables were determined by the Spearmam correlation test. For all tests, p <0.05 was considered significant. Based on the results, the intake of 3 g daily of soluble mate for 30 and 60 days promoted significant increases in TAC values and in the activity of the antioxidant enzyme PON-1, in comparison to the CG or to the respective baseline periods (p <0.05). Increased PON-1 was also observed after 7 days of consumption of 3 g of soluble mate (p<0.05). The consumption of soluble mate prevented the elevation of TOS after 60 days (p<0.05). In general, there were no significant changes between eutrophic, overweight or obese individuals. Regarding the glycemic profile, the consumption of 3 g of soluble mate for 30 and 60 days contributed to minimize elevations in serum glucose and insulin concentrations and in HOMA-IR values (which measures insulin resistance), to maintain ?-cell activity and to prevent decreased insulin sensitivity, compared to CG adolescents (p<0.05). Eutrophic, overweight or obese students presented the same response to soluble mate. In the anthropometric variables, consumption of mate soluble during 30 and 60 days by MG adolescents decreased body weight, Z-score (1.1 and 9.9%, respectively, p<0.05) and WC, mainly in obese adolescents, and contributed to minimize the increase of %BF and the reduction of BM, in relation to the CG students (p