Impact of EPA and DHA Supplementation on Plasma Biomarkers of Inflammation (n3)

Subclinical inflammation is now indisputably recognized as a key etiological factor in the development of atherosclerosis and subsequent cardiovascular disease. Obesity and related dysmetabolic states including metabolic syndrome (MetS) are highly prevalent causes of subclinical inflammation. Obesity and MetS are both diet and lifestyle-related and there is a growing body of literature suggesting that specific nutrients, such as long chain omega-3 polyunsaturated fatty acids (LCn-3PUFA), may attenuate the pro-inflammatory state associated with these conditions. However, careful review of existing literature on this topic reveals important gaps in knowledge, the purported anti-inflammatory effects of LCn-3PUFA even being questioned by many. Significant confounding attributable to study design, sample size and biomarker selection may be responsible in part for inconsistencies in the literature on LCn-3PUFA and inflammation. We also found that evidence available to date (for and against) is based primarily on secondary analyses, as most of the studies published were not primarily designed to investigate inflammation as a primary outcome. It remains unclear whether the different LCn-3PUFA, primarily docosahexaenoic acid (DHA, 22:6n-3) and eicosapentaenoic acid (EPA, 20:5n-3), have similar effects on pro-inflammatory processes as almost all studies were undertaken using a mix of LCn-3PUFA. Whether efficacy of EPA and DHA is influenced by sex/gender is also unknown. Finally, a better understanding of the systemic and tissue-specific mechanisms underlying the anticipated anti-inflammatory effects of different LCn-3PUFA in MetS would also be of great value. Addressing these gaps has important public health implications, considering that LCn-3PUFA supplements are broadly and indiscriminately recommended for the prevention of cardiovascular disease. The overarching objective of the proposed research is to compare the anti-inflammatory effects of EPA and DHA in men and women