Change in blood levels of eicosapentaenoic acid and posttraumatic stress symptom: A secondary analysis of data from a placebo-controlled trial of omega3 supplements
Introduction
Eicosapentaenoic acid (EPA; 20:5n-3) is suggested to be protective against posttraumatic stress disorder (PTSD) from a prospective cohort (Matsuoka et al., 2013a) and a cross-sectional observation (Kalinic et al., 2014). Briefly, we found that serum levels of EPA and arachidonic acid (AA; 20:4n-6) immediately after the trauma were inversely associated with subsequent risk for developing PTSD (Matsuoka et al., 2013a), and Kalinic et al. found that lower serum EPA levels were associated with the severity of clinical symptoms in PTSD (Kalinic et al., 2014). Before having promising observational findings of EPA for preventing PTSD, we have already begun to conduct a randomized placebo-controlled trial to examine the efficacy of omega-3 fatty acid supplements rich in docosahexaenoic acid (DHA; 22:6n-3) for preventing PTSD based on the theory (Matsuoka, 2011) for 4 years. Our theory at that time was promoting adult neurogenesis by DHA supplementation early in the post-trauma period might facilitate the clearance of fear memory from the hippocampus and consequently minimize PTSD symptoms (Matsuoka, 2011). We finally found that DHA did not demonstrate an advantage over placebo for prevention of PTSD (Matsuoka et al., 2015). Recent study showed that EPA was beneficial for the prevention of interferon-α-induced depression in patients with hepatitis C virus, while DHA had only modest effect (Su et al., 2014). This suggests that EPA is potentially a suitable preventive strategy for psychiatric disorder associated with inflammation. The optimal balance or dosage of EPA and DHA for prevention of developing PTSD is unknown, but it should be possible to presume whether EPA might have a potential to suppress PTSD symptoms in omega3 group. This secondary analysis of data from our previous trial aimed to determine whether change in blood levels of EPA during the trial are associated with PTSD symptoms.
Section snippets
Methods
The data for the present study came from a randomized double-blind, placebo-controlled trial (NCT00671099). The participants were recruited between December 2008 and June 2013 from the intensive care unit of the National Disaster Medical Center in Japan. The study was approved by the Research Ethics Committee of National Disaster Medical Center and University of Toyama, and all participants signed an informed consent form. The percentages of EPA, DHA, and AA were measured in erythrocyte
Results
As previously reported, there were no differences between the two arms in any of the baseline characteristics, including erythrocyte levels of fatty acids and CAPS total score (10.78 [omega3] vs. 9.22 [placebo], p=.57) at 3 months (Matsuoka et al., 2015). Also, there were significant increases in EPA (1.23 at baseline to 1.64 at 3 months) and DHA (6.40 at baseline to 8.94 at 3 months) and a significant decrease in AA (12.33 at baseline to 10.90 at 3 months) in the omega3 arm compared with the
Discussion
Increased level of EPA+DHA, EPA, EPA: AA ratio and EPA: DHA ratio during the trial was associated with low severity of PTSD symptoms in patients receiving omega3 supplements at 3 months. DHA supplementation resulted in an apparent linear increase in EPA concentrations, presumably through retroconversion of DHA to EPA (Arterburn et al., 2006). Our findings should be involved in this mechanism. This study suggests the potential efficacy of EPA rather than DHA for minimizing PTSD symptoms after
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