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Acute Ingestion of Long-Chain (n-3) Polyunsaturated Fatty Acids Decreases Fibrinolysis in Men with Metabolic Syndrome. Montegaard C, Tulk HM, Lauritzen L, Tholstrup T, Robinson LE. J Nutr. 2009 Nov 4. [Epub ahead of print] PMID: 19889809 doi:10.3945/jn.109.111427 Individuals with metabolic syndrome (MetS) often have elevated plasma plasminogen activator inhibitor-1 (PAI-1) and tissue plasminogen activator (t-PA), contributing to an increased risk of cardiovascular disease. PAI-1 and t-PA may be affected by chronic (n-3) long-chain PUFA [(n-3)LCPUFA] supplementation; however, the acute impact of fat ingestion on these risk factors has not been established. Our objective was to investigate the acute effect of (n-3)LCPUFA on plasma PAI-1, t-PA, and platelet aggregation. We conducted a randomized crossover study in which men (n = 8, ≥45 y) with MetS consumed water or a high-saturated fat beverage (1 g fat/kg body weight) with either a high or low content of (n-3)LCPUFA. Blood samples were collected over 8 h to measure triacylglycerol (TAG), PAI-1, t-PA, and platelet aggregation. Both fat loads resulted in a significant increase in whole blood TAG concentration, plasma PAI-1 and t-PA concentrations, and PAI-1 activity, as well as a significant decrease in t-PA activity during the postprandial period. Interestingly, PAI-1 concentration and activity increased more following the high (n-3)LCPUFA compared with the low (n-3)LCPUFA beverage (P < 0.05). Furthermore, the high (n-3)LCPUFA beverage resulted in a lower t-PA activity (P < 0.05), whereas the effects of the 2 fat loads on the plasma t-PA concentration and platelet aggregation did not differ. Overall, acute intake of a high (n-3)LCPUFA beverage shifted the balance between plasma PAI-1 and t-PA, which might indicate a lower capacity for fibrinolysis

"THURSDAY, Dec. 17 (HealthDay News) -- In a surprise finding, Canadian researchers report that the immediate effect of the fish oil fatty acids that are good for the heart is a short-term increase in blood fats and the molecules that help them form clots. "We were surprised to find that the acute response has some potentially negative effects in comparison to what you might expect from chronic, long-term intake," said Lindsay E. Robinson, an associate professor of nutrition at the University of Guelph, and leader of the group reporting the finding in the January issue of the Journal of Nutrition. However, the study results shouldn't affect the current recommendation for eating more oily fish to get the omega-3 polyunsaturated acids that reduce the risk of blood clots that can cause heart attacks and stroke, Robinson said. "The recommendation to increase intake is very well-studied, and this doesn't change it," she said. And the effects were seen in a selected group of middle-aged men with metabolic syndrome, a combination of high blood pressure, obesity and elevated blood fat levels, Robinson noted. In the study, eight men had controlled intake of three regimens: high doses of omega-3 fatty acids, low doses of them and just plain water. Robinson and her colleagues measured several blood components involved in clotting, including fats and clotting factors such as plasminogen-activator inhibitor-1 (PAI-1) for the following eight hours. PAI-1 inhibits the destruction of blood clots, so high levels of it in the blood increase the risk of artery-blocking clots. The researchers found that both omega-3 fatty acid regimens increased blood fat and clotting factor activity. But the increase in clotting factor was greater for the higher doses of omega-3 fatty acids than for the lower intakes. Robinson said her group hopes to do further studies of the immediate effects of omega-3 fatty acid intake. "We need to look at the mechanisms, why blood lipid levels go up," she