DHA As An Anti-Inflammatory Nutrient

Background:Dietary fish or fish oil rich in n–3 fatty acids (n–3 FAs), eg, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), ameliorate inflammatory reactions by various mechanisms. Whereas most studies have explored the effects of predominantly EPA-based n–3 FAs preparations, few have addressed the effects of n–3 FAs preparations with DHA as the main FA.

Objective:The objective was to determine the effects of 6 mo of dietary supplementation with an n–3 FAs preparation rich in DHA on release of cytokines and growth factors from peripheral blood mononuclear cells (PBMCs).

Design:In a randomized, double-blind, placebo-controlled trial, 174 Alzheimer disease (AD) patients received daily either 1.7 g DHA and 0.6 g EPA (n–3 FAs group) or placebo for 6 mo. In the present study blood samples were obtained from the 23 first randomized patients, and PBMCs were isolated before and after 6 mo of treatment.

Results:Plasma concentrations of DHA and EPA were significantly increased at 6 mo in the n–3 FAs group. This group also showed significant decreases of interleukin (IL)-6, IL-1β, and granulocyte colony-stimulating factor secretion after stimulation of PBMCs with lipopolysaccharide. Changes in the DHA and EPA concentrations were negatively associated with changes in IL-1β and IL-6 release for all subjects. Reductions of IL-1β and IL-6 were also significantly correlated with each other. In contrast, this n–3 FA treatment for 6 mo did not decrease tumor necrosis factor-, IL-8, IL-10, and granulocyte-macrophage colony-stimulating factor secretion.

Conclusion:AD patients treated with DHA-rich n–3 FAs supplementation increased their plasma concentrations of DHA (and EPA), which were associated with reduced release of IL-1β, IL-6, and granulocyte colony-stimulating factor from PBMCs. This trial was registered at clinicaltrials.gov as NCT00211159.