Stearic acid-rich diets do not increase thrombotic risk factors in healthy males

Plasma Phospholipid Fatty Acids and Risk of Venous Thromboembolism: Mendelian Randomization Investigation

Circulating fatty acids may affect thrombosis but epidemiological data on the associations between fatty acids and risk of venous thromboembolism (VTE) are limited and conflicting. We conducted a Mendelian randomization study to examine the causal associations of 10 circulating fatty acids with VTE risk. Genetic variants strongly associated with ten fatty acids and without linkage disequilibrium were selected as instrumental variables from the Cohorts for Heart and Aging Research in Genomic Epidemiology Consortium. Genetic associations for VTE and its subtypes were obtained from the International Network Against Venous Thrombosis Consortium (30,234 cases and 172,122 controls) and the FinnGen study (11,288 VTE cases and 254,771 controls). Estimates from the two data sources were combined. Per standard deviation increase in genetically predicted fatty acid levels, the combined odds ratio (OR) of VTE was 0.88 (95% confidence interval [CI] 0.84–0.92) for α-linolenic acid, 0.92 (95% CI 0.90–0.95) for linoleic acid, 0.85 (95% CI 0.78–0.92) for palmitoleic acid, 0.77 (95% CI 0.77–0.84) for oleic acid, 1.16 (95% CI 1.10–1.23) for eicosapentaenoic acid, 1.10 (95% CI 1.06–1.14) for docosapentaenoic acid, 1.06 (95% CI 1.04–1.08) for arachidonic acid, and 1.19 (95% CI 1.11–1.28) for stearic acid. Genetically predicted levels of docosahexaenoic acid or palmitoleic acid were not associated with VTE risk. Four and eight out of ten genetically predicted fatty acid levels were associated with risk of pulmonary embolism and deep vein thrombosis, respectively. This study suggests that strategies targeting at fatty acids may act as prevention approaches for VTE.

Postprandial activation of hemostatic factors: role of dietary fatty acids

Intake of dietary fat is an important determinant of the plasma concentration of triacylglycerol-rich lipoproteins, and the degree of alimentary lipemia is reported to have effects on hemostatic status including platelet function. Although association between the amount of dietary fat intake, lipemic response and certain cardiovascular disease (CVD) risk factors (VIIa and PAI-1) has been reported, the significance of the fatty acid composition of ingested fat for the postprandial lipid concentrations and the hemostatic factors is still unclear. Accumulating evidence suggests a relationship between dietary fatty acids and emerging hemostatic CVD risk factors, although much of this evidence is incomplete or conflicting. In order to improve our knowledge in this area, sufficient sample size in future studies are required to take into account of the genetic variation (gene polymorphisms for VII, PAI-1), sex, physical activity, stage of life factors, and sufficient duration to account for adaptation for definitive conclusions.

Fats, lipids and blood coagulation

Saturated and n-3 fatty acids, postprandial lipaemia, and the combined effects of fatty acids and lipid-lowering drugs have been of principal interest in recent studies in the field of dietary fats, lipids and haemostasis. The sex-specific effect of individual saturated fatty acids on coagulation factor VII activity has been discovered, and the significant effect of factor VII R353Q polymorphism on the postprandial response has also been found. An increased intake of n-3 fatty acids or fat reduction when combined with intensive lifestyle interventions may lead to reduced thrombotic potential in type 2 diabetic patients and obese individuals. Furthermore, positive effects on haemostasis by combined treatment with long-chain n-3 fatty acids and simvastatin indicate that n-3 fatty acids may be of some relevance with lipid-lowering drugs. The possible unfavourable effect of n-3 fatty acids on plasminogen activator inhibitor-1 activity is still a matter of dispute, but recent studies suggest that n-3 fatty acids, including alpha-linolenic acid, may have antithrombotic effects by enhancing protein C activity.