ABSTRACT
<p><b>BACKGROUND</b>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.</p><p><b>OBJECTIVE</b>This study examined the effects of ALE supplementation on metabolic parameters of the TCF7L2-rs7903146 polymorphism in patients with metabolic syndrome (MetS).</p><p><b>DESIGN, SETTING, PARTICIPANTS AND INTERVENTIONS</b>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.</p><p><b>MAIN OUTCOME MEASURES</b>Anthropometric indices, blood pressure, glucose and lipid profile levels were measured before and after the study. Moreover, patients were genotyped for TCF7L2 polymorphism.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSION</b>The responses of insulin and HOMA-IR to ALE supplementation have shown an interaction with single-nucleotide polymorphism rs7903146 in TCF7L2.</p><p><b>TRIAL REGISTRATION</b>Iranian Registry of Clinical Trial IRCT201409033320N9.</p>