Eicosapentaenoic acid and docosahexaenoic acid from fish oils: differential associations with lipid responses

Abstract

Fish-oil supplementation can reduce circulating triacylglycerol (TG) levels and cardiovascular risk. This study aimed to assess independent associations between changes in platelet eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and fasting and postprandial (PP) lipoprotein concentrations and LDL oxidation status, following fish-oil intervention. Fiftyfive mildly hypertriacylglycerolaemic (TG 1·5-4·0 mmol/l) men completed a double-blind placebo controlled cross over study, where individuals consumed 6 g fish oil (3 g EPA þ DHA) or 6 g olive oil (placebo)/d for two 6-week intervention periods, with a 12-week wash-out period in between. Fish-oil intervention resulted in a significant increase in the platelet phospholipid EPA (+491 %, P,0·001) and DHA (+44 %, P,0·001) content and a significant decrease in the arachidonic acid (210 %, P,0·001) and g-linolenic acid (224 %, P,0·001) levels. A 30 % increase in ex vivo LDL oxidation (P,0·001) was observed. In addition, fish oil resulted in a significant decrease in fasting and PP TG levels (P,0·001), PP non-esterified fatty acid (NEFA) levels, and in the percentage LDL as LDL-3 (P¼0·040), and an increase in LDLcholesterol (P¼0·027). In multivariate analysis, changes in platelet phospholipid DHA emerged as being independently associated with the rise in LDL-cholesterol, accounting for 16 % of the variability in this outcome measure (P¼0·030). In contrast, increases in platelet EPA were independently associated with the reductions in fasting (P¼0·046) and PP TG (P¼0·023), and PP NEFA (P¼0·015), explaining 15 -20 % and 25 % of the variability in response respectively. Increases in platelet EPA þ DHA were independently and positively associated with the increase in LDL oxidation (P¼0·011). EPA and DHA may have differential effects on plasma lipids in mildly hypertriacylglycerolaemic men.

Effects of n–3 Supplementation on Plasma and Liver Phospholipid Fatty Acids Profile in Aged Wistar Rats

“…An inhibition of HMG-CoA reductase activity in DHA-EE treated rats maight have contributed to the hypocholesterolemic effect. 34 According to Leigh-Firbank et al 35 fish oil can reduce TG and cardiovascular risk. Increases in platelet EPA and DHA were postively associated with the increase in LDL oxidation.…”

Dietary effects on oxidation of low-density lipoprotein and atherogenesis

“…Polyunsaturated fatty acids are found mostly in vegetable oils (omega-6 fatty acids, which have the first double bond on the carbon in position 6 from the omega end), and fatty fish (omega-3 fatty acids, which have the first double bond on the carbon in position 3 from the omega end). The effects of polyunsaturated fatty acids on LDL oxidation are complex with conflicting results, but at least some studies on omega-3 fatty acids report a protective effect against LDL oxidation [7], and most studies on omega-6 fatty acids actually report increased susceptibility of LDL particles to oxidation [39]. Although monounsaturated fatty acids, therefore, appear to more effectively protect against LDL particle oxidation than polyunsaturated fats (and indeed most studies focused on these compounds have been comparing these two types of lipids), it should be said that all unsaturated fatty acids result in improved lipid profiles, reduced overall LDL concentrations, and reduced risk of CVD.…”

Effect of lycopene on biomarkers of oxidative stress in rats supplemented with ω−3 polyunsaturated fatty acids

“…According to Buettner et al (2006), high-fat fish oil-fed rats showed enhanced expression of genes for lipid oxidation. Some authors have found an increase in the levels of oxidation biomarkers in both plasma LDL and tissue homogenates after EPA and DHA supplementation (Higdon et al, 2000;Leigh-Firbank et al, 2002;Puiggró s, Chacó n, Armadans, Clapés, & Planas, 2002) while others have shown opposite results, even including antioxidant properties associated with these two fatty acids (Barbosa et al, 2003;Erdogan et al, 2004;Frankel et al, 1994;Frenoux et al, 2001;Gordoa et al, 2002;Higgins et al, 2001;Hsu, Lee, & Chen, 2001;Thorlaksdottir et al, 2006).…”