TCF7L2-rs7903146 polymorphism modulates the effect of artichoke leaf extract supplementation on insulin resistance in metabolic syndrome: a randomized, double-blind, placebo-controlled trial

Background: Transcription factor 7-like 2 (TCF7L2)-rs7903146 polymorphism is associated with increased risk of type 2 diabetes. The response of insulin and insulin resistance to artichoke leaf extract (ALE) may be affected by TCF7L2-rs7903146 polymorphism. Objective: This study examined the effects of ALE supplementation on metabolic parameters of the TCF7L2-rs7903146 polymorphism in patients with metabolic syndrome (MetS). Design, setting, participants and interventions: This double-blind clinical trial was conducted on 80 patients with MetS in Sina Clinic, Khoy, Iran. The patients were randomized into ALE or placebo groups to receive either ALE (1800 mg/d as four tablets) or matching placebo for 12 weeks. Main outcome measures: Anthropometric indices, blood pressure, glucose and lipid profile levels were measured before and after the study. Moreover, patients were genotyped for TCF7L2 polymorphism. Results: ALE supplementation decreased insulin level and the homeostasis model assessment of insulin resistance (HOMA-IR) in patients with the TT genotype of TCF7L2-rs7903146 polymorphism (P < 0.05). There was no significant interaction between blood pressure, glucose and lipid profile response to ALE supplementation. Conclusion: The responses of insulin and HOMA-IR to ALE supplementation have shown an interaction with single-nucleotide polymorphism rs7903146 in TCF7L2. Trial registration: Iranian Registry of Clinical Trial IRCT201409033320N9.