n–3 Fatty acids and cardiovascular disease: evidence explained and mechanisms explored

Abstract

Long chain n-3 PUFAs (polyunsaturated fatty acids) are found in fatty fish and in fish oils. Substantial evidence from epidemiological and case-control studies indicates that consumption of fish, fatty fish and long-chain n-3 PUFAs reduces the risk of cardiovascular mortality. Secondary prevention studies using long-chain n-3 PUFAs in patients post-myocardial infarction have shown a reduction in total and cardiovascular mortality, with an especially potent effect on sudden death. Long-chain n-3 PUFAs have been shown to decrease blood triacylglycerol (triglyceride) concentrations, to decrease production of chemoattractants, growth factors, adhesion molecules, inflammatory eicosanoids and inflammatory cytokines, to lower blood pressure, to increase nitric oxide production, endothelial relaxation and vascular compliance, to decrease thrombosis and cardiac arrhythmias and to increase heart rate variability. These mechanisms most likely explain the primary and secondary cardiovascular protection afforded by long-chain n-3 PUFA consumption. A recent study suggests that long-chain n-3 PUFAs might also act to stabilize advanced atherosclerotic plaques, perhaps through their anti-inflammatory effects. As a result of the robust evidence in their favour, a number of recommendations to increase intake of long-chain n-3 PUFAs have been made.

Iron overload thalassemic cardiomyopathy: Iron status assessment and mechanisms of mechanical and electrical disturbance due to iron toxicity

“…However, vitamin C is not useful because it can promote iron toxicity by reducing iron redox status (Fe 3+ to Fe 2+ ) and enhancing cellular uptake, which may worsen cardiac dysfunction in patients at risk for iron overload cardiomyopathy (55). Omega-3 PUFAs, abundant in fish oil, have been known for their cardioprotective effects (81). Although they are substrates in lipid peroxidation, the by-products of lipid peroxidation were not increased after omega-3 PUFA supplement (82).…”

Rationale and use of n-3 fatty acids in artificial nutrition

“…Fish oil contains the very long-chain n-3 PUFA EPA and DHA. There is strong evidence for health benefits of these fatty acids, especially with regard to CVD (33)(34)(35)(36) . They act to modify tissue and blood lipid metabolism, blood lipid concentrations, blood coagulation, immune function, inflammation and endothelial function (37)(38)(39)(40)(41) .…”

Dose-dependent increases in heart rate variability and arterial compliance in overweight and obese adults with DHA-rich fish oil supplementation

“…Epidemiological evidence also suggests that HRV is improved in populations that have a higher intake of LC n-3 PUFA over a prolonged period (20) . The effects of LC n-3 PUFA on HR and HRV are likely to be attributable to increased parasympathetic activation (19) .…”