Effects of alpha-linolenic acid versus those of EPA/DHA on cardiovascular risk markers in healthy elderly subjects.
Effects of alpha-linolenic acid versus those of EPA/DHA on cardiovascular risk markers in healthy elderly subjects.
Year: 2006
Authors: Goyens, PLL, Mensink, RP.
Publication Name: Eur. J. Clin. Nutr.
Publication Details: Volume 60, Page 978.
Abstract:
Marine based omega 3 fatty acids (EPA/DHA) have been shown in a number of intervention studies to reduce the risk of coronary heart disease (CHD) through several well established mechanisms. Similarly, ALA also protects against CHD. Specific omega 3 fatty acids (FA) appear to exert individual and quite specific effects on cardiovascular risk markers. For example, EPA and DHA appear to lower triacylglycerol values, whereas ALA reduced total and LDL-cholesterol. All three omega 3 FAs exhibit comparable and positive effects on blood coagulation and fibrinolytic factors. Many of these studies have been performed in young and middle-aged subjects. The aim of this research was to investigate the effects of ALA and EPA/DHA on cardiovascular risk markers including lipoprotein profile, coagulation and fibrinolytic factors, and endothelial function in elderly subjects. Thirty-seven mildly hypercholesterolemic subjects (men=14; women=23) aged 60-78 years participated in this randomized double-blind nutritional interventional study. For a 3-week run in period, all subjects consumed an oleic acid rich diet. For the subsequent 6-weeks, participants were randomly allocated to continue on the run in diet (control; n=10), consume a diet rich in ALA (6.8g/day ALA; n=13), or consume a diet rich in EPA and DHA (1.05g EPA + 0.55g DHA/day; n=14). The experimental fat was provided in the form of shortening, in which a specific amount of products (pies, cakes, spreads) made with the shortening were provided weekly. Each subject consumed on average 30g of experimental shortening per day. Fasting blood samples were obtained at baseline, and during the last week of both the run-in and experimental periods and used for subsequent analysis. No significant changes in body weight between the three groups during the course of the study were observed. Levels of total cholesterol, LDL-cholesterol, HDL-cholesterol, triacylglycerol, and apoA-1 were not different between the omega 3 rich diets and the control diet. However, compared to the ALA diet, the EPA/DHA diet resulted in an increase in LDL-cholesterol values of 0.39mmol/L. An increase in apoB concentrations of 14 mg/dl compared to the control diet, and 12 mg/dl compared to the ALA-rich diet was noted for the EPA/DHA diet. EPA and DHA consumption resulted in a significant increase in tissue factor pathway inhibitor (TFPI) of 14.6%. TFPI is a single-chain polypeptide which can reversibly inhibit Factor Xa (Xa). While Xa is inhibited, the Xa-TFPI complex can subsequently also inhibit the FVIIa-TF complex. Both FVIIa and Factor Xa are important proteins involved in the coagulation cascade leading to thrombosis. TFPI contributes significantly to the inhibition of FVIIa and Xa in vivo. No other differences, however, in other markers for blood coagulation and fibrinolysis, or markers for endothelial function were observed between the three groups. Based on these results, the authors concluded that omega 3 fatty acids from both plant and marine sources have different effects on blood lipid profiles in elderly subjects. ALA was observed to alter concentrations of LDL-cholesterol and apoB more favorably than EPA/DHA, whereas EPA/DHA appeared to exert a more beneficial effect on TFPI and thus on the coagulation pathway.
