O impacto da intervenção com suplementação de ácido alfa-lipólico e alfa-tocoferol no controle de resistência à insulina e outros componentes da síndrome metabólica em pacientes com diabetes mellitus tipo 2 / The impact of alfa-lipoic acid and alfa-tocopherol supplementation in the control of insulin resistance and other metabolic syndrome components in patients with type 2 diabetes mellitus.

Andreia Madruga de Oliveira

Introduction. Associated with infect-contagious diseases and malnutrition, diabetes mellitus type 2 is admittedly an important problem of Public Health, if limitations affecting individuals´ quality of living and high social costs further to treatments, losses in productivity and shortening of life expectancy are taken into account. One of the characteristics that predispose the population to diseases is the presence of Metabolic Syndrome, characterized, among other factors, by central obesity, hypertriglyceridemia, hypercholesterolemia, high blood pressure and insulin resistance. In addition to the usual medicinal therapy and despite controversial results, the use of antioxidants has played an important role in the reduction of oxidative stress and in the improvement in the effect of insulin when glucose is used all over the body tissues. Objectives. To assess the impact of the introduction of combined antioxidant alfa-lipoic acid and alfa- tocopherol in the components of the Metabolic Syndrome in patients with type-2 Diabetes mellitus. Methodology. Double-blind, placebo-controlled, randomized trial. During 16 weeks, 102 patients with type-2 diabetes were analyzed. All patients were users of the local Health System of Jundiaí, Sao Paulo, Brazil. Four groups were formed. Group 1 was given placebo (n=26), whilst group 2 individuals were given a daily supplement of 800mg alfa-tocopherol (n=25). Group 3 individuals were given a daily supplement of 600mg alfa-lipoic acid. Finally, group 4 individuals were given both antioxidants (n=25). The following rates were checked before and after antioxidant supplementation for all participants of the trial: level of alfa-tocopherol, glucose and fast insulin, lipid fractions, rate of urinary albumin excretion and C-reactive protein (CRP), as well as anthropometry and blood pressure. The effect of the supplementation was analyzed through the difference detected after the supplementation through variance analysis, comparing the differences among and within the various groups. Results. The average age of the patients was 61.2 ± 8.5 years, 64.7% of them being female. Before the supplementation, 17.6% of the 102 diabetic patients displayed hypovitaminosis E (deficient) and 57.8% (low levels). The acceptable plasmatic levels were detected in 24.5% of the sample. After the supplementation, the deficiency was detected in 15.7%, low levels in 37.2% and acceptable levels, in 47.1%. There was a significant difference (p<0.001) in the levels before and after supplementation in the groups which were given vitamin E, though in these groups there has been a reduction of 71% and 60% in their deficiency levels in groups 2 and 4, respectively (<2,2Nmol/L/ mmol/L). With respect to their body mass index (BMI), only 9.8% of the diabetic had a normal BMI before the supplementation and remained as such till the end of the study. Before the supplementation, the majority of the cohort (46.1%) was overweight and 27.5% had level I obesity. After the supplementation, these indexes went up to 50% and 22.6% overweight and level I obesity, respectively. After the supplementation, there was a reduction in the levels of CRP, their rate of microalbuminuria and lipid fractions, as well as the reduction of prevalence of patients who presented high levels of these indicators, which is characteristic of the metabolic syndrome, however insignificant (p>0.05). Even though there has been a reduction of the Homeostasis Model Assessment (HOMA-IR) in the group which received ?-lipoic acid, compared with the group which received placebo, there was no significant difference in these indexes before and after the supplementation. Conclusion. The results obtained in this study have shown that antioxidant supplementation, namely with vitamin E (alfa-tocopherol) and alfa-lipoic acid and a combination of both, did not play a positive role in insulin resistance and in the components of the metabolic syndrome in patients with type-2 diabetes.

AUTOR(ES)

DATA DE PUBLICAÇÃO

RESUMO

ASSUNTO(S)

ACESSO AO ARTIGO

Documentos Relacionados