Pregnant women’s seafood intake and fatty acid composition in red blood cells – a randomized controlled trial with dietary cod

Abstract

Background: Seafood is the predominant source of the dietary long-chain omega-3 polyunsaturated fatty acids (LCn-3PUFA) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Consumption of these fatty acids (FAs) during pregnancy are associated with increased neural and visual development in fetus, and decreased risk of postpartum depression in mothers. The proportions of DHA in the fetus is positively correlated with the mothers, making the maternal intake crucial for fetal levels. There are dietary guidelines for fatty fish consumption in relations to its content of EPA and DHA. However, such guidelines does not exist for lean fish and cod which is a great source of LCn-3PUFAs, as 200g of cod contributes with 480 mg EPA and DHA, double of the daily adequacy level set by the European Food Safety Authority (EFSA). Objective: To investigate if an increased intake of cod during pregnancy have an impact on FA content in red blood cells (RBC), with focus on the marine associated LCn-3PUFAs, in addition to evaluating seafood and omega-3 (n-3) supplement intakes. Methods: A total of 137 women with prim parous, singleton pregnancy from Bergen, Norway, were enrolled in the dietary two-armed randomized controlled trial “Mommy’s Food”. The pregnant women were randomized into intervention group consuming 400 gram of cod per week, or the control group continuing their habitual diet. The intervention lasted for 16 weeks, from gestational week 20 to gestational week 36. A Gas Chromatograph–Flame Ionization Detector was used to measure FA content in RBC. Seafood and cod and intake were calculated using a food frequency questionnaires (FFQ) and a weight registration form. Results: There were no significant differences in the FA content at post-intervention between the intervention- and control- group. The intervention group had a significant increase in the relative amount of DHA (p<.002) and stability in the n-3 index, with no correlation to cod intake. Both groups had a decrease in Σ omega-6 (n-6) and stable Σ n-3 FAs, resulting in an increase of the n-3:n-6 ratio. During intervention 71% reported eating seafood for dinner >2-3 times/week, and 82% consumed n-3 supplements at baseline and post intervention. Conclusion: There was no significant difference for the FA content between the groups at post intervention. Therefore, in this study, an intervention with dietary cod did not have a significant impact on the marine associated LCn-3PUFA in RBC of pregnant women with a high intake of seafood and a large percentage taking n-3 supplements.