title: Effect of dietary alpha-linolenic acid on blood inflammatory markers: a systematic review and meta-analysis of randomized controlled trials.
abstract: OBJECTIVE
  The aim of the current meta-analysis was to investigate the effect of increasing dietary ALA intake on the blood concentration of inflammatory markers including tumor necrosis factor (TNF), interleukin 6 (IL-6), C-reactive protein (CRP), soluble intercellular adhesion molecule-1 (sICAM-1), and soluble vascular cell adhesion molecule-1 (sVCAM-1) in adults.
  
  
  METHODS
  After a systemic search on PubMed, Embase, and Cochrane library and bibliographies of relevant articles, 25 randomized controlled trials that met the inclusion criteria were identified.
  
  
  RESULTS
  No significant effect of dietary ALA supplementation was observed on TNF (SMD: -0.03, 95% CI -0.36 to 0.29), IL-6 (SMD: -0.17, 95% CI -0.46 to 0.12), CRP (SMD: -0.06, 95% CI -0.24 to 0.12), sICAM-1 (SMD: -0.06, 95% CI -0.26 to 0.13), and sVCAM-1 (SMD: -0.24, 95% CI -0.56 to 0.09). Subgroup analysis revealed that increasing dietary ALA tends to elevate CRP concentration in healthy subjects. However, the null effect of ALA supplementation on other inflammatory markers was not changed in various subgroups, indicating that the results are stable. Meta-regression results revealed a negative relationship between the effect size on CRP and its baseline concentration. No significant publication bias was observed for all inflammatory markers as suggested by funnel plot and Begg's test.
  
  
  CONCLUSIONS
  Our meta-analysis did not find any beneficial effect of ALA supplementation on reducing inflammatory markers including TNF, IL-6, CRP, sICAM-1, and sVCAM-1. However, in healthy subjects, ALA supplementation might increase CRP concentration.
authors.affiliation: State Key Laboratory of Food Science and Technology, Synergetic Innovation Center of Food Safety and Nutrition, School of Food Science and Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, People's Republic of China.
authors.forename: Hang
authors.initials: H
authors.lastname: Su
authors.affiliation: State Key Laboratory of Food Science and Technology, Synergetic Innovation Center of Food Safety and Nutrition, School of Food Science and Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, People's Republic of China.
authors.forename: Ruijie
authors.initials: R
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Food Science and Technology, Synergetic Innovation Center of Food Safety and Nutrition, School of Food Science and Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, People's Republic of China.
authors.forename: Ming
authors.initials: M
authors.lastname: Chang
authors.affiliation: State Key Laboratory of Food Science and Technology, Synergetic Innovation Center of Food Safety and Nutrition, School of Food Science and Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, People's Republic of China.
authors.forename: Jianhua
authors.initials: J
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Food Science and Technology, Synergetic Innovation Center of Food Safety and Nutrition, School of Food Science and Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, People's Republic of China.
authors.forename: Qingzhe
authors.initials: Q
authors.lastname: Jin
authors.affiliation: State Key Laboratory of Food Science and Technology, Synergetic Innovation Center of Food Safety and Nutrition, School of Food Science and Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu, 214122, People's Republic of China. wangxg1002@gmail.com.
authors.forename: Xingguo
authors.initials: X
authors.lastname: Wang
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000009:adverse effects / Q000627:therapeutic use*; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000032:analysis; D002908:Chronic Disease / Q000517:prevention & control*; D019587:Dietary Supplements / Q000009:adverse effects; D019317:Evidence-Based Medicine; D006801:Humans; D018836:Inflammation Mediators / Q000097:blood* / Q000737:chemistry; D018799:Intercellular Adhesion Molecule-1 / Q000097:blood / Q000737:chemistry; D015850:Interleukin-6 / Q000097:blood; D016032:Randomized Controlled Trials as Topic; D012995:Solubility; D014409:Tumor Necrosis Factor-alpha / Q000097:blood; D019010:Vascular Cell Adhesion Molecule-1 / Q000097:blood / Q000737:chemistry; D017962:alpha-Linolenic Acid / Q000009:adverse effects / Q000627:therapeutic use*
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D015415:Biomarkers; C573420:ICAM1 protein, human; C508600:IL6 protein, human; D018836:Inflammation Mediators; D015850:Interleukin-6; C439524:TNF protein, human; D014409:Tumor Necrosis Factor-alpha; D019010:Vascular Cell Adhesion Molecule-1; D017962:alpha-Linolenic Acid; D018799:Intercellular Adhesion Molecule-1; D002097:C-Reactive Protein
keywords: Alpha-linolenic acid; Inflammatory markers; Meta-analysis; Randomized controlled trials