Influence of n-6 versus n-3 Polyunsaturated Fatty Acids in Diets Low in Saturated Fatty Acids on Plasma Lipoproteins and Hemostatic Factors

Abstract

Modification of dietary fat composition may influence hemostatic variables, which are associated with increased risk of coronary heart disease (CHD). To address this question, we performed a controlled feeding study on 26 healthy male nonsmoking subjects with diets of differing fat composition. For the first 3 weeks, the subjects were given a diet calculated to supply 30% energy as total fat: 8% as monounsaturated, 4% as polyunsaturated, and 16% energy as saturated fatty acids, respectively (saturated diet). This was followed immediately by two diets taken in random order, each of 3-week duration and separated by an 8-week washout period on the subject's usual diet. Both diets were calculated to supply 30% of energy as fat: 14% monounsaturated, 6% as polyunsaturated, and 8% energy as saturated fatty acids. They both provided 5 g (approximately 1.7% energy) more of polyunsaturated fatty acids than the saturated fat diet; in one diet as long-chain n-3 fatty acids (n-3 diet) and in the other as linoleic acid (n-6 diet). Fasting plasma lipids, lipoproteins, and hemostatic factors were measured on the final 3 days of each dietary period. In a subset of 9 subjects the postprandial responses to a test meal were studied on the penultimate day of each period, each meal having the fat composition of its parent diet. On the n-3 diet compared with the n-6 diet, plasma triglyceride, HDL3 cholesterol, apoprotein AII, and fibrinogen concentrations were lower and HDL2 cholesterol concentration was higher (P = .0001, P = .003, P = .0001, P = .004, and P = .001, respectively). On both the n-3 and n-6 diets compared with the saturated diet, fasting plasma total and LDL cholesterol, apoprotein B, beta-thromboglobulin concentrations, and platelet counts were lower (P < .0001, P < .0001, P < .001, P < .01, and P < .05 respectively) and plasma Lp(a) and von Willebrand factor concentrations were higher (P = .02 and P < .01, respectively). Fasting factor VII coagulant activity (VIIc) was increased and apoprotein AI concentration reduced following the n-3 diet (P = .004 and P = .01, respectively) compared with the saturated diet. Plasma fibrinogen concentration was significantly greater following the n-6 diet than on the saturated diet (P = .02). Postprandially, plasma triglyceridemia was greater on the n-6 diet and lowest on the n-3 diet (P < .001) with the saturated diet being intermediate. Plasma VIIc was increased at 4 hours following the standardized test meals on the n-3 and n-6 diets (both P < .05) but not on the saturated diet. An increased intake of long chain n-3 fatty acids decreases fasting plasma triglyceride and apoprotein AII concentrations and increases HDL2 cholesterol concentrations and results in less postprandial lipemia but leads to an increase in VIIc. An increased intake of linoleic acid may raise plasma fibrinogen concentration. Decreasing the intake of saturated fatty acids reduces plasma LDL cholesterol and apoprotein B without affecting HDL cholesterol concentration independent of the type of polyunsaturated fat...

Meta-analysis of the effects of n-3 polyunsaturated fatty acids on haematological and thrombogenic factors in type 2 diabetes

“…Increased fasting coagulant factor VII after n-3 PUFA supplementation has been reported in two other trials in healthy subjects [63,64]. However, one of these two trials found a simultaneous reduction in prothrombin factor X required in the process of clotting [64], and the authors suggested that clotting was therefore not necessarily activated.…”

Influence of triacylglycerol structure of stearic acid-rich fats on postprandial lipaemia

“…Although the magnitude of postprandial lipaemia depends on the fat content of a meal, it can be enhanced by consecutive fat-containing meals (Jackson et al 2002). Both the background diet as well as the fatty acid composition of the test meal can influence the extent of lipaemia (Weintraub et al 1988;Zampelas et al 1994a;Sanders et al 1997Sanders et al , 2000Oakley et al 1998;Roche et al 1998). High intakes of long-chain n-3 fatty acids tend to decrease postprandial lipaemia, probably by acutely suppressing VLDL synthesis and thus reducing competition from VLDL for removal of chylomicron remnants.…”

Optimization of the carrot leaf dehydration aiming at the preservation of omega-3 fatty acids

“…28 In contrast, a higher serum n-6/n-3 ratio may increase the risk of coronary heart disease. 26 The ratio n-6/n-3 fatty acids was 0.36 in the carrot leaves studied. Results expressed as means ± standard deviation (n=3).…”

“…Today's western cultures have an n-6/n-3 approximately 15 for northern Europe and 16.7 for current US differing from human evolution low ratio. 26 The optimal balance between dietary LNA and LA has shown to reduce the potential for asthma 27 and may prevent thrombosis and atherosclerosis. 28 In contrast, a higher serum n-6/n-3 ratio may increase the risk of coronary heart disease.…”