Red Blood Cell Omega-6 Fatty Acids and Biomarkers of Inflammation in the Framingham Offspring Study

Background/objectives: Chronic inflammation is recognized as an important risk factor for a variety of health disorders. Omega-6 polyunsaturated fatty acids (n-6 PUFAs), particularly linoleic (LA) and arachidonic acid (AA), have been shown to be either pro- or anti-inflammatory, and researchers have advocated both for and against reducing their dietary intake. This study sought to correlate the levels of ten inflammation-related biomarkers across multiple pathways with red blood cell (RBC) membrane levels of the major dietary and circulating n-6 PUFAs. Methods: We included 2777 participants (mean age: 66 ± 9 years, 54% women, 9.8% minorities) from the Framingham Offspring and minority-enriched Omni cohorts, and calculated partial correlation coefficients. Results: After multivariable adjustment, RBC LA was inversely correlated (all p ≤ 0.05) with five markers of inflammation, receptors, or pathways: C-reactive protein (r = -0.06); soluble interleukin-6 (r = -0.15); intercellular adhesion molecule-1 (r = -0.09); monocyte chemoattractant protein-1 (r = -0.07); and P-selectin (r = -0.07). RBC AA was inversely correlated (all p ≤ 0.05) with soluble interleukin-6 (r = -0.10); intercellular adhesion molecule-1 (r = -0.14); monocyte chemoattractant protein-1, and (r = -0.06); and osteoprotegerin (r = -0.07). Lipoprotein-associated phospholipase-A2 mass and activity, urinary isoprostanes, and tumor necrosis factor receptor-2 were not significantly correlated with LA or AA. Conclusions: In our large community-based study, we observed weak but statistically significant inverse associations between several types of inflammatory biomarkers with RBC n-6 PUFAs. Our findings do not support the hypothesis that omega-6 fatty acids are pro-inflammatory.