Reduction of prothrombin and Factor V levels following supplementation with omega-3 fatty acids is sex dependent: a randomised controlled study Melinda Phang a , Fiona E. Scorgie b , Michael Seldon b , Manohar L. Garg a, ⁎ , Lisa F. Lincz b a Nutraceuticals Research Group, School of Biomedical Sciences and Pharmacy, University of Newcastle, Hunter Medical Research Institute, New Lambton Heights, NSW 2305, Australia b Hunter Haematology Research Group, Calvary Mater Newcastle, Waratah, NSW 2298, Australia Received 16 July 2013; received in revised form 27 April 2014; accepted 1 May 2014 Abstract Background: LCn-3PUFA comprised of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) offer cardioprotection involving a decrease in coagulant activity; however, the evidence is equivocal. We have previously demonstrated that the acute (24 h) effects and chronic (4 weeks) effects of LCn-3PUFA supplementation on platelet aggregation in human subjects are sex specific. This study investigated the mechanisms of the sex-dependent effects of LCn-3PUFA with 4 weeks supplementation of EPA-rich vs. DHA-rich oils on procoagulant and platelet activity in healthy subjects. Design: A double-blinded, placebo-controlled randomised trial was conducted in 94 healthy adults: male (n=41) and female (n=53). Platelet coagulation parameters including factors I, II, V, VII, VIII, IX, X, vWF:Ag and endogenous thrombin potential were measured at baseline and 4 weeks postsupplementation with EPA-rich or DHA-rich oil capsules. Results: We have previously reported that platelet aggregation is specifically reduced by supplementation with EPA in males and DHA in females. This sex- specific effect was also observed for decreases in plasma levels of Factor II (-7.9±3.8%, P=.026), Factor V (-6.5±4.5%, P=.022) and vWF:Ag (-7.3±2.1%, P=.034) and was most pronounced in males supplemented with EPA. In contrast, DHA-mediated reduction in platelet aggregation in females was not accompanied by any significant changes in the coagulation parameters tested. Conclusion: Significant interactions between sex and specific LCn-3PUFA exist to reduce procoagulant activity differentially in males vs. females and could have profound effects on managing risk of thrombotic disease. © 2014 Elsevier Inc. All rights reserved. Keywords: Hemostatic markers; Procoagulant activity; LCn-3PUFA; Sex-dependent; Platelets 1. Introduction Consumption of LCn-3PUFA, comprised of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), is associated with a reduction in the incidence and severity of thrombotic diseases such as cardiovascular disease and stroke [1,2]. Despite over three decades of study, the precise mechanisms of these effects remain to be elucidated. The effects of LCn- 3PUFA on platelets and blood coagulation are variable [3]. Some studies suggest that LCn-3PUFA acts as an antithrombotic agent since it inhibits ex vivo platelet aggregation activity [4]. Conversely, others have reported that EPA/DHA have shown minimal benefit [5,6]. Furthermore, some studies describe a moderate reduction in Factor I (fibrinogen) levels, thrombin generation [7] and coagulation factors V, VII and X [8–11] with fish oil supplementation, whereas other groups fail to detect this [3,6,12]. In attempts to resolve this longstanding conflict, the appreciation of independent effects of EPA and DHA on cardiovascular risk factors is now an emerging entity. Controlled human studies have demonstrated that DHA alone offers equally important cardioprotective effects, although it is often present in lower amounts in fish oil supplements [13,14]. However, these studies controlling for dosage and concentration ratios of EPA:DHA alone provided no further clarifications with respect to platelet function and hemostatic variables [14,15]. This disparity concerning the effects of LCn-3PUFA on hemostatic parameters may be explained by sex-specific differences in platelet reactivity with EPA or DHA supplementation. The majority of studies, including the early research that laid the foundation for the cardioprotective effects of LCn-3PUFA, have ignored sex as a confounding factor and inadvertently biased their studies since they were predominately conducted in male subjects [3,15–17]. We have previously demonstrated the existence of sex-specific platelet responses with individual LCn-3PUFA both in vitro [18] and in vivo after short-term exposures [19,20] and following a 4-week supplementation period [21]. The aim of the present investigation was to extend our findings to examine the effect on procoagulant activity in parallel with ex vivo platelet aggregation. More specifically, this study aimed to examine the mechanisms of the sex-dependent effects of LCn-3PUFA with 4 weeks supplementation of EPA-rich vs. DHA-rich oils on procoagulant activity, thrombin generation and coagulation in healthy males and females. Available online at www.sciencedirect.com ScienceDirect Journal of Nutritional Biochemistry xx (2014) xxx – xxx ⁎ Corresponding author. 305C Medical Sciences Building, University of Newcastle, Callaghan, NSW 2308, Australia. Tel.: +61 2 4921 -5647; fax: +61 2 4921 2028. E-mail address: manohar.garg@newcastle.edu.au (M.L. Garg). http://dx.doi.org/10.1016/j.jnutbio.2014.05.001 0955-2863/© 2014 Elsevier Inc. All rights reserved.