Association of foods enriched in conjugated linoleic acid (CLA) and CLA supplements with lipid profile in human studies: a systematic review and meta-analysis
What this study found
Overall, CLA was associated with a favorable effect on LDL cholesterol, and this was the most consistent lipid benefit across the review. Both CLA supplements and CLA-enriched foods were linked to LDL-C reductions, but the food-based interventions appeared to produce a broader improvement in lipid profile, although the additional lipid changes were mainly non-significant. CLA supplements generally lowered LDL-C without consistent effects on total cholesterol, HDL-C, or triglycerides. Across the included trials, effects on non-LDL lipids were mixed, with many null findings and some studies…
- Study & population
- Systematic review and meta-analysis of human clinical trials assessing CLA exposure and lipid outcomes.
- Intervention
- The review evaluated oral conjugated linoleic acid (CLA) delivered either as supplements or as CLA-enriched foods.
- Key limitation
- The evidence base was heterogeneous, with major differences in CLA form, dose, isomer composition, and delivery vehicle across trials.
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Open PDFOriginal abstract
Abstract Objective The present study aimed to review the association of conjugated linoleic acid (CLA) consumption in two forms, foods enriched in CLA and CLA supplements, with serum lipid profile in human studies. Design Systematic review and meta-analysis. Setting Search process was conducted in PubMed, Cochrane Library, Google Scholar, Scopus and Science Direct. Clinical trials that investigated the association of CLA intakes either in the form of supplements or enriched foods with lipid profile in healthy adults were included. All outcomes were recorded as continuous variables, and the effect size was measured by analysis of the mean and standard deviation before and after the intervention for case and control groups. Subjects Healthy adult population. Results CLA supplementation was associated with a significant decrease in LDL cholesterol (mean difference=−0·218; 95 % CI −0·358, −0·077; P=0·002), a non-significant decrease in HDL cholesterol (mean difference=−0·051; 95 % CI −0·188, 0·086; P=0·468), a non-significant increase in total cholesterol (mean difference=0·009; 95 % CI −0·128, 0·146; P=0·896) and a non-significant decrease in TAG (mean difference=−0·065; 95 % CI −0·20, 0·07; P=0·344). Foods enriched with CLA were associated with significantly decreased LDL cholesterol (mean difference=−0·231; 95 % CI −0·438, −0·024; P=0·028), non-significantly increased HDL-C (mean difference=0·075; 95 % CI −0·121, 0·270; P=0·455), non-significantly decreased total cholesterol (mean difference=−0·158; 95 % CI −0·349, 0·042; P=0·124) and non-significantly decreased TAG (mean difference=−0·078; 95 % CI −0·274, 0·117; P=0·433). Conclusions According to our analysis, consumption of foods enriched with CLA or CLA supplements has favourable effects on LDL cholesterol levels.