Dietary omega-3 fatty acids aid in the modulation of inflammation and metabolic health

Abstract

This article focuses on the role of omega-3 fatty acids as precursors for lipid signaling molecules known as oxylipins. Although omega-3 fatty acids are beneficial in autoimmune disorders, inflammatory diseases and heart disease, they are generally underrepresented in the American diet. A literature review confirms that the consumption of omega-3 fatty acids - whether in food sources such as walnuts, flax seeds and fatty fish (including salmon and sardines), or in supplements - is associated with decreased morbidity and mortality. This growing body of evidence, including the results of a recent study of patients with kidney disease, highlights the need to measure omega-3 fatty acids and their oxylipin products as markers of metabolic health and biomarkers of disease. In addition, there is substantial evidence of the need to increase the omega-3 fatty acid content of American diets to optimize metabolic health.

Fig. 1

Dietary sources and enzymatic conversion pathways of omega-3 and omega-6 fatty acid precursors. The omega-3 precursor alpha-linolenic acid (ALA) is found in walnuts and flax seeds, and the omega-6 precursor linoleic acid (LA) is found in corn and vegetable oils. Both are converted by desaturase and elongase enzymes into their long-chain derivatives: ALA is converted to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA); and LA is converted to arachidonic acid (ARA). ARA is found in animal products, such as beef, and EPA and DHA are found in fatty fish, such as sardines.

Fig. 2

Cellular mechanisms involved in producing oxylipin derivatives of omega-3 and omega-6 fatty acids. A stimulus such as cell wall injury activates transporter proteins, moving Ca²⁺ ions into the cell. This stimulates the release of fatty acids from nuclear membrane phospholipids (phosphatidycholine [PC]) by the enzyme phospholipase A2 (PLA₂), and the conversion of omega-3 (eicosapentaenoic [EPA], docosahexaenoic [DHA] and alpha-linolenic [ALA] acid) and omega-6 (arachidonic [ARA] and linoleic [LA] acid) fatty acids into signaling oxylipin products via the COX (cyclooxygenase), LOX (lipoxygenase) and CYP 450 (cytochrome P450) enzymes. These oxylipins are signaling molecules that help regulate inflammation, increasing and decreasing this important immune response within the cell (autocrine) and in neighboring cells (paracrine).

Walnuts, flax seeds and salmon are good sources of omega-3 fatty acids, important nutrients that are generally deficient in American diets.

Eggs from chickens that have been fed flax have higher concentrations of omega-3 fatty acids, which have been shown in a number of studies to be beneficial to human health.

Evidence is mounting that omega-3 fatty acids can moderate inflammation in the body and help reduce the risk and symptoms of kidney disease, heart disease and arthritis. Above, a patient undergoes dialysis for kidney disease.