Effect of low-ratio n-6/n-3 PUFA on blood lipid level: a meta-analysis



The aim of this meta-analysis was to evaluate the effects of low-ratio n-6/n-3 PUFA on blood lipid levels.


We searched the PubMed, Embase, and Cochrane Library databases for randomized controlled trials of n-6/n-3 PUFA interventions up to March 2019. The change values were calculated as weighted mean differences (WMDs) by using a random-effect model. Subgroup analysis and meta-regression were used to explore the source of heterogeneity.


A total of 30 randomized controlled trials with 1368 participants were identified. Compared with control, low-ratio n-6/n-3 PUFA significantly reduced triglyceride (TG) concentration (WMD: − 0.079 mmol/L, 95% confidence interval (CI): − 0.148 mmol/L to − 0.009 mmol/L, p = 0.026) and increased high-density lipoprotein cholesterol (HDL-C) concentration (WMD: 0.033 mmol/L, 95% CI: 0.007 to 0.058 mmol/L, p = 0.012). Subgroup analysis revealed that the effects of low-ratio n-6/n-3 PUFA on blood lipid levels were better for a longer time. The effects of α-linolenic acid on total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) concentrations were more obvious among participants. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) had more significant effects on TG and HDL-C concentrations. No significant publication bias was observed for TG and HDL-C, as suggested by the results of Begg’s test and Egger’s test.


Low-ratio n-6/n-3 PUFA significantly reduced TG concentration and increased HDL-C concentration. The beneficial effects of low-ratio n-6/n-3 PUFA on TG, TC, HDL-C, and LDL-C concentrations were enhanced with time. However, n-3 PUFA derived from plants significantly reduced TC and LDL-C concentrations, and n-3 PUFA derived from EPA and DHA significantly reduced TG concentration and increased HDL-C concentration.

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Data availability

Some or all data, models, or code generated or used during the study are available from the corresponding author by request.


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I would like to extend my sincere gratitude to my supervisors, Tongcheng Xu and Hanxue Hou, for their instructive advice and useful suggestions on my thesis. I am also deeply indebted to all the other teachers and students for their help to me.


This work is supported by the National Key R&D Program of China (2018YFD0401104); by the Key R & D project of Shandong Province (2018YYSP011); by the Taishan Scholar Project (Feng-Hong Huang); and by the Key R & D project of Shandong Province (2019GHZ031). The funders had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.

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Literature search: Na Li and Min Jia; methodology: Qianchun Deng; data statistics and analysis: Fenghong Huang and Min Jia; funding acquisition: Fenghong Huang, Tongcheng Xu; discussion analysis: Qianchun Deng and Tongcheng Xu; writing original draft: Na Li; writing review and editing: Hanxue Hou, Zhen Wang; approval of final manuscript: all authors.

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Correspondence to Hanxue Hou or Tongcheng Xu.

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We the undersigned declare that this manuscript entitled “The effect of low-ratio n-6/n-3 PUFA on blood lipid: a meta-analysis” is original, has not been published before, and is not currently being considered for publication elsewhere.

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The authors are the following: Na Li, Min Jia, Qianchun Deng, Zhen Wang, Fenghong Huang, Hanxue Hou, Tongcheng Xu.

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Li, N., Jia, M., Deng, Q. et al. Effect of low-ratio n-6/n-3 PUFA on blood lipid level: a meta-analysis. Hormones (2020). https://doi.org/10.1007/s42000-020-00248-0

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  • N-6/n-3 PUFA
  • Blood lipid
  • Randomized controlled trial
  • Meta-analysis