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The effect of conjugated linoleic acid supplementation in comparison with omega-6 and omega-9 on lipid profile: a graded, dose–response systematic review and meta-analysis of randomized controlled trials

Camellia Akhgarjand, Aryan Tavakoli, S. Samavat, Amir Bagheri, A. Anoushirvani, Atieh Mirzababaei, Mohammad Reza Amini, M. Ghorbi et al.

Frontiers in Nutrition, 2024

1,476 participants · 6 citations

Abstract

Conjugated linoleic acid (CLA) is a geometrical isomer of linoleic acid, which has anti-inflammatory, anti-diabetic, anti-cancer, and anti-obesity properties. However, the studies reported inconstant results about the CLA-related effects on lipid profiles. As a result, meta-analysis and systematic review were performed to survey the CLA supplementation-related effect on lipid profile including high-density lipoprotein (HDL), low-density lipoprotein (LDL), total cholesterol (TC), and triglycerides (TG). To identify the relevant research, a systematic comprehensive search was initiated on the medical databases such as Scopus and PubMed/Medline until December 2022. The overall effect size was estimated by weighted mean difference (WMD) and 95% confidence interval (CI) in a random effect meta-analysis. In the final quantitative analysis, the meta-analysis considered 35 randomized controlled trials (RCTs) with 1,476 participants (707 controls and 769 cases). The pooled results demonstrated that CLA supplementation, compared with olive oil, significantly increased serum TG levels (WMD: 0.05 mmol/L; 95% CI: 0.01 to 0.1; p = 0.04; I2 = 0.0%, p = 0.91). With regard to TC level, CLA supplementation compared with placebo significantly reduced TC concentrations (WMD: −0.08 mmol/L; 95% CI: −0.14 to −0.02; p < 0.001; I2 = 82.4%). Moreover, the non-linear dose–response analysis indicated a decreasing trend of TC serum level from the 15th week of CLA supplementation compared with olive oil…

How strong is the evidence?

Evidence Hub reads this as a meta-analysis, done in people. Its evidence level is 1 of 5 (Highest · pooled evidence). Pooled evidence from several studies sits at the top of the evidence pyramid. Reported size: 1,476 participants or records.

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