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Effects of fish oil supplementation on biomarkers of vascular endothelial function in middle-aged and older adults: a randomized controlled trial.

  • 2026
  • Food & function 17(3)
    • Chunxia Quan
    • Wei Tang
    • Yuting Qin
    • Zhaoyang Nian
    • Zhongxia Li
    • Limei Mao

Study Design

Type
Randomized Controlled Trial (RCT)
Sample size
n = 240
Population
240 participants, middle-aged and elderly adults
Methods
randomized to four groups receiving 0 g, 1 g, 2 g, or 4 g daily of fish oil for 12 weeks
Duration
12 weeks
  • Large Human Trial
  • Rigorous Journal
Objective: This trial evaluated marine-derived omega-3 supplementation for primary cardiovascular prevention in middle-aged and elderly adults, focusing on endothelial activation markers and vasodilation. Methods: 240 participants were randomized to four groups receiving 0 g, 1 g, 2 g, or 4 g daily of fish oil (containing 129 mg DHA and 182 mg EPA per gram) for 12 weeks. Fasting blood samples were analyzed for fatty acids and endothelial function biomarkers (NO, ET-1, ICAM-1, MCP-1, Ox-LDL) at baseline and post-intervention. Results: Baseline characteristics and dietary intake did not differ significantly among groups (P > 0.05). Post-intervention analysis revealed a significant increase (P < 0.05) in serum EPA and DHA in all fish oil groups except the control group. The key between-group result was a significantly greater reduction in ICAM-1 (-24.21% vs. -10.90%; P = 0.026) and MCP-1 (-27.38% vs. -14.92%; P = 0.024) in the 1 g d-1 group compared to control, with higher doses (2 g d-1 and 4 g d-1) not showing incremental benefit. No other biomarkers (NO, ET-1, Ox-LDL) showed significant between-group differences. Notably, within-group changes included increased NO in the 2 g d-1 group and decreased ET-1 in the 1 g d-1 and 4 g d-1 groups from baseline. Conclusions: This study found that low-dose fish oil significantly reduced endothelial inflammatory markers (ICAM-1, MCP-1) with a U-shaped dose-response in a community-based middle-aged/elderly population, suggesting optimal anti-inflammatory effects at modest intake. No effects were seen on vasodilatory or oxidative lipid markers.

Research Insights

  • Fish Oil→Improved Vasodilation

    No effects were seen on vasodilatory or oxidative lipid markers.

    Effect
    Neutral
    Effect size
    Small
    Dose
    0 g/day, 1 g/day, 2 g/day, or 4 g/day
  • Fish Oil→Increased Nitric Oxide Level

    No other biomarkers (NO, ET-1, Ox-LDL) showed significant between-group differences. Notably, within-group changes included increased NO in the 2 g d-1 group

    Effect
    Neutral
    Effect size
    Small
    Dose
    0 g/day, 1 g/day, 2 g/day, or 4 g/day
  • Fish Oil→Reduced Endothelin-1 Level

    No other biomarkers (NO, ET-1, Ox-LDL) showed significant between-group differences. Notably... decreased ET-1 in the 1 g d-1 and 4 g d-1 groups from baseline.

    Effect
    Neutral
    Effect size
    Small
    Dose
    0 g/day, 1 g/day, 2 g/day, or 4 g/day
  • Fish Oil→Reduced ICAM-1 Level

    The key between-group result was a significantly greater reduction in ICAM-1 (-24.21% vs. -10.90%; P = 0.026) in the 1 g d-1 group compared to control

    Effect
    Beneficial
    Effect size
    Moderate
    Dose
    0 g/day, 1 g/day, 2 g/day, or 4 g/day
  • Fish Oil→Reduced Monocyte Adhesion

    MCP-1 (-27.38% vs. -14.92%; P = 0.024) in the 1 g d-1 group compared to control

    Effect
    Beneficial
    Effect size
    Moderate
    Dose
    0 g/day, 1 g/day, 2 g/day, or 4 g/day
  • Fish Oil→Reduced Oxidized Low-Density Lipoprotein Level

    No other biomarkers (NO, ET-1, Ox-LDL) showed significant between-group differences.

    Effect
    Neutral
    Effect size
    Small
    Dose
    0 g/day, 1 g/day, 2 g/day, or 4 g/day
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