Invited commentary: dietary polyunsaturated Fatty acids and chronic systemic inflammation--a potentially intriguing link.

It remains largely unclear whether consumption of total and individual polyunsaturated fatty acids (PUFAs) is associated with chronic systemic inflammation in healthy, free-living individuals. While available evidence (stemming principally from mechanistic studies) has indicated that greater intake of n-6 PUFAs may lead to increased levels of inflammation-for instance, by their acting as precursors to proinflammatory eicosanoids and increasing levels of oxidized linoleic acid metabolites-n-3 PUFAs are precursors to some antiinflammatory eicosanoids. New human data from a Dutch prospective study, the Rotterdam Study-as presented by Muka et al. ( Am J Epidemiol. 2015;181(11):846-856) in this issue of the Journal-now make an important contribution to the relatively scarce literature on the association of dietary n-3 and n-6 PUFAs with serum levels of C-reactive protein (CRP), a key marker of inflammation, in a general population. The study by Muka et al. benefitted from repeated CRP measurements, comprehensive correction for potential confounding, and wide-ranging sensitivity analyses. The findings show no significant trend regarding n-3 PUFAs but indicate an important inverse association between n-6 PUFAs and chronic systemic inflammation. This study provides support for existing dietary guidelines, which encourage consumption of a combination of n-3 and n-6 PUFAs in the diet.