SUN-065 Effects of Conjugated Linoleic Acid (CLA) on Insulin Resistance and BMI in Subjects with and without the Metabolic Syndrome: A Systematic Review and Meta-Analysis

*RC and RC equally contribute as the main reviewers Background: CLA supplementation has been widely used by the general population as a weight reduction agent. In-vitro and animal studies have reported beneficial metabolic effects while reports in humans have been mixed, with some even reporting adverse effects. The aim of the present study is to review and synthesize the available evidence from randomized controlled trials (RCTs) of CLA on body weight (BMI) and insulin resistance (HOMA-IR). Methods: We conducted a systematic literature search to identify studies up to December 2017. Only RCTs with CLA t10-c12 isomer or mix 50:50 CLA t10-c12 and c9-t11 as intervention on individuals with or without components of the metabolic syndrome were selected. Individual study results were pooled to obtain weighted mean differences (WMDs) with 95% confidence intervals (CI), funnel plots assessed small study effects and subgroup analysis helped explore a priori identified sources of heterogeneity. Results: A total of 24 RCTs met the inclusion criteria and 19 were eligible for meta-analysis of one or more outcomes of interest. For BMI, the combined result from 15 individual studies showed a reduction of 0.26 units (95%CI -0.47, -0.05) in the intervention group vs placebo (p=0.017). No statistically significant difference was observed from pooling 7 studies on HOMA-IR, a few of which rather indicated a negative effect. Conclusions: Our review demonstrates a weight-lowering influence of CLA. However, although the effect seems consistent, its magnitude does not convincingly suggest clinical relevance. In terms of insulin resistance, there does not seem to be any beneficial effect, and small studies showing adverse effect warrants further scrutiny.