Effects of Omega-3 Fatty Acids on Inflammatory Markers in Cerebrospinal Fluid and Plasma in Alzheimer’s Disease: The OmegAD Study

<i>Background:</i> ω-3 fatty acids (ω-3 FAs) found in dietary fish or fish oils are anti-inflammatory agents that may influence Alzheimer’s disease (AD). <i>Objective:</i> To study the effects of dietary ω-3 FA supplementation on inflammatory markers in cerebrospinal fluid (CSF) and plasma from patients with mild to moderate AD. <i>Methods:</i> Thirty-five patients (70.3 ± 8.2 years) were randomized to a daily intake of 2.3 g ω-3 FAs or placebo for 6 months. The inflammatory markers interleukin (IL)-6, tumour necrosis factor-α and soluble interleukin-1 receptor type II (sIL-1RII) were analysed in CSF and plasma at baseline and at 6 months. The AD markers tau-protein, hyperphosphorylated tau-protein and β-amyloid (Aβ_1–42) were assessed in CSF. High-sensitivity C-reactive protein was assessed in plasma. A possible relation to the <i>APOE </i>genotype was investigated. <i>Results:</i> There was no significant treatment effect of ω-3 FAs on inflammatory and AD biomarkers in CSF or on inflammatory markers in plasma, nor was there any relation with <i>APOE</i>. A significant correlation was observed at baseline between sIL-1RII and Aβ_1–42 levels in CSF. <i>Conclusions:</i> Treatment of AD patients with ω-3 FAs for 6 months did not influence inflammatory or biomarkers in CSF or plasma. The correlation between sIL-1RII and Aβ_1–42 may reflect the reciprocal interactions between IL-1 and Aβ peptides.