Effects of epigallocatechin gallate on total antioxidant capacity, biomarkers of systemic low-grade inflammation and metabolic risk factors in patients with type 2 diabetes mellitus: the role of FTO-rs9939609 polymorphism

Introduction: Type 2 diabetes mellitus (T2DM) is known as one of the most common metabolic diseases and FTO polymorphism has been implicated in the susceptibility to this disease. Epigallocatechin-3-gallate (EGCG) has shown favorable effects on risk factors related to T2DM. The present study aimed to investigate the effects of EGCG on total antioxidant capacity, biomarkers of systemic low-grade inflammation and metabolic risk factors in patients with T2DM considering the role of FTO polymorphism.

Material and methods: In this double-blind randomized clinical trial, 60 patients with T2DM (20-60 years) were randomly allocated to three groups. Group 1 received 300 mg of EGCG (TT genotype). Group 2 received 300 mg of EGCG (AA + AT genotypes) and Group 3 received placebo. We genotyped FTO (rs9939609) and measured body mass index (BMI), blood pressure, profile lipid, interleukin-6, high sensitivity C-reactive protein and total antioxidant capacity, before and after the intervention, at 2 months.

Results: In carriers of A allele, EGCG intervention caused a significant decrease in BMI, diastolic blood pressure (DBP), mean arterial pressure and serum cholesterol level compared with placebo (p < 0.05). Also, we found a significant gene-treatment interaction effect between FTO-rs9939609 and EGCG on BMI and DBP (P > 0.05).

Conclusions: These findings suggest that carriers of the risk alleles (A) of FTO-rs9939609 have a better response to EGCG in improving BMI and DBP in patients with T2DM.