Effect of Alpha-Linolenic Acid Supplementation on Cardiovascular Disease Risk Profile in Individuals with Obesity or Overweight: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

"Conflict of Interest The authors report no conflicts of interest."

"Funding This work was funded by the National Natural Science Foundation of China (Grant No. 82173509) and grants from the Chinese Nutrition Society Research Fund for Dietary Reference Intake (DRI)."

"This systematic review and meta-analysis were prospectively registered in the search strategy (PROSPERO Registration No. CRD42023429563). The review protocol can be accessed at =https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023429563) and was strictly followed when conducting. It was reported in line with the PRISMA statement () []. All studies included in this review were confirmed to be free of ethical/moral concerns. Therefore, the need for ethics committee consent was waived. Overweight and obesity are highly prevalent worldwide and are associated with cardiovascular disease (CVD) risk factors, including systematic inflammation, dyslipidemia, and hypertension. Alpha-linolenic acid (ALA) is a plant-based essential polyunsaturated fatty acid associated with reduced CVD risks. This systematic review and meta-analysis aimed to investigate the effects of supplementation with ALA compared with the placebo on CVD risk factors in people with obesity or overweight (International Prospective Register of Systematic Reviews Registration No. CRD42023429563). This review included studies with adults using oral supplementation or food or combined interventions containing vegetable sources of ALA. All studies were randomly assigned trials with parallel or crossover designs. The Cochrane Collaboration tool was used for assessing the risk of bias (Version 1). PubMed, Web of Science, Embase, and Cochrane library databases were searched from inception to April 2023. Nineteen eligible randomized controlled trials, including 1183 participants, were included in the meta-analysis. Compared with placebo, dietary ALA supplementation significantly reduced C-reactive protein concentration (standardized mean difference [SMD] = –0.38 mg/L; 95% confidence interval [CI]: –0.72, –0.04), tumor necrosis factor-α concentration (SMD = –0.45 pg/mL; 95% CI: –0.73, –0.17), triglyceride in serum (SMD = −4.41 mg/dL; 95% CI: –5.99, –2.82), and systolic blood pressure (SMD = –0.37 mm Hg; 95% CI: –0.66, –0.08); but led to a significant increase in low-density lipoprotein cholesterol concentrations (SMD = 1.32 mg/dL; 95% CI: 0.05, 2.59). ALA supplementation had no significant effect on interleukin-6, diastolic blood pressure, total cholesterol, or high-density lipoprotein cholesterol (all P ≥ 0.05). Subgroup analysis revealed that ALA supplementation at a dose of ≥3 g/d from flaxseed and flaxseed oil had a more prominent effect on improving CVD risk profiles, particularly where the intervention duration was ≥12 wk and where the baseline CVD profile was poor."