Key Findings:
This review assesses research to assess the optimal dietary intake of the n6 to n3 ratio which the authors indicate should be around 1 to 4/1, rather than the current range of 10/1 to 20/1. In conjunction with these changes in the ratio has come increases in inflammatory diseases including cardiovascular disease, obesity, IBD, rheumatoid arthritis, and cancer as well as neurodegenerative and psychiatric illnesses and depression. Atherosclerosis is a “systemic disease” characterised by low-grade arterial inflammatory lesions. Decreases in ALA, EPA and DHA seen in endothelial cell PUFA deficiency, increases the production of pro-inflammatory cytokines and free radicals which results in the development of insulin resistance. As n3 PUFA have been shown to alleviate the progression of IBD, while n6 PUFA have been implicated in the origin of IBD, the importance of a balance in the ratio of n6/n3 PUFA in today’s dietary regime is highlighted. Decreasing n6 PUFA intake (especially AA) has been associated with a reduction in inflammatory disease.
ABSTRACT:
Omega 6 (n6) polyunsaturated fatty acids (PUFA) (e.g., arachidonic acid (AA)) and omega 3 (n3) PUFA (e.g., eicosapentaenoic acid (EPA)) are precursors to potent lipid mediator signalling molecules, termed “eicosanoids,” which have important roles in the regulation of inflammation. In general, eicosanoids derived from n6 PUFA are proinflammatory while eicosanoids derived from n3 PUFA are anti inflammatory. Dietary changes over the past few decades in the intake of n6 and n3 PUFA show striking increases in the (n6) to (n3) ratio (15 to 1), which are associated with greater metabolism of the n6 PUFA compared with n3 PUFA. Coinciding with this increase in the ratio of (n6) to (n3) PUFA are increases in chronic inflammatory diseases such as nonalcoholic fatty liver disease (NAFLD), cardiovascular disease, obesity, inflammatory bowel disease (IBD), rheumatoid arthritis, and Alzheimer’s disease (AD). By increasing the ratio of (n3) to (n6) PUFA in the Western diet, reductions may be achieved in the incidence of these chronic inflammatory diseases. (Authors abstract)