Effect of flaxseed oil supplementation on lipid profile in adults: A systematic review and dose-response meta-analysis of randomized controlled trials

Objective: This study evaluated the effects of flaxseed oil (FO, derived from Linum usitatissimum) supplementation on lipid profile parameters in adults.Materials and Methods: A systematic search was conducted across PubMed, Scopus, Google Scholar, and Web of Science up to February ۲۰۲۵, targeting randomized controlled trials (RCTs) that compared FO supplementation with a control group. A random-effects meta-analysis calculated lipid markers' weighted mean difference (WMD) and ۹۵% confidence interval (CI).Results: Thirty-six RCTs involving ۱,۹۵۹ participants were analyzed. FO supplementation significantly reduced triglyceride (TG) levels (WMD: -۸.۰۴ mg/dl; ۹۵% CI: -۱۵.۶۳ to -۰.۴۵; p=۰.۰۳۸) but had no significant effect on total cholesterol (TC) (WMD: -۱.۱۵ mg/dl; ۹۵% CI: -۵.۷۵ to ۳.۴۴; p=۰.۶۲), low-density lipoprotein-cholesterol (LDL-C) (WMD: ۱.۰۱ mg/dl; ۹۵% CI: -۱.۳۵ to ۳.۴۱; p=۰.۴۱), or high-density lipoprotein cholesterol (HDL-C) (WMD: ۰.۱ mg/dl; ۹۵% CI: -۱.۲۶ to ۱.۴۷; p=۰.۸۸). Subgroup analyses revealed greater TG and TC reductions in interventions <۱۲ weeks (TG: WMD: -۱۶.۸۶ mg/dl, p=۰.۰۰۵; TC: WMD: -۳.۵ mg/dL, p=۰.۰۳) and significant TG decreases in obese participants (WMD: -۱۸.۲۹ mg/dl, p=۰.۰۳). HDL-C increased significantly in individuals with baseline HDL-C ≤۴۰ mg/dl (WMD: ۱.۳۵ mg/dl; ۹۵% CI: ۰.۳ to ۲.۴; p=۰.۰۱). Non-linear dose-response analysis showed significant associations between FO dose and LDL-C (p=۰.۰۳۹) and alpha-linolenic acid intake with LDL-C (p=۰.۰۳۹) and TC (p=۰.۰۲۷).Conclusion: FO supplementation effectively lowers TG, especially in obese individuals and shorter interventions, and raises HDL-C in those with low baseline levels. While LDL-C and TC show minimal overall change, non-linear dose effects suggest that higher FO and α-Linolenic acid (ALA) doses may influence these markers, necessitating further research on optimal dosing.

کلیدواژه ها:

Flaxseed oil Lipid profile Triglycerides LDL cholesterol HDL cholesterol Omega ، ۳ fatty acids