MicroRNAs are involved in adipogenesis and have metabolic and endocrine functions.40 Previous studies showed that microRNA-221 was upregulated in patients with obesity with increased insulin resistance, BMI, and inflammation.16,41,42 We found that butyrate reduced microRNA-221 expression, and the effect paralleled with BMI, HOMA-IR, insulin, and the proinflammatory cytokine IL-6 level reduction. The gene discussed is INS; the disease is obesity due to melanocortin 4 receptor deficiency.