Influence of Ingestion of Eicosapentaenoic Acid-Rich Fish Oil on Oxidative Stress at the Menstrual Phase: A Randomized, Double-Blind, Placebo-Controlled, Parallel-Group Trial.

Background: This study examines the effect of the supplements on the redox reaction in menstrual cycle. Participants took eicosapentaenoic acid (EPA)-rich fish oil supplements over two menstrual cycles. Materials and Methods: For this randomized, double-blind, placebo-controlled trial, 21 female members of a university basketball team were selected. Participants were allocated into the EPA/docosahexaenoic acid (DHA) group (EG, n = 11) and control group (CG, n = 10) through stratified randomization. The EG and CG took 3600 mg fish oil (containing 900 mg EPA and 403 mg DHA) and 3600 mg corn oil (without EPA and DHA), respectively, every day for two menstrual cycles. The redox reaction was measured four times: the menstrual and follicular phases in two menstrual cycles. Results: There was a significant difference in reactive oxygen metabolites (d-ROMs) and potential antioxidant capacity during the menstrual phase by the main effect of time (before and after intake) in EG and CG (p < 0.01). In a subsequent test, d-ROMs were significantly lower after intake in EG and CG (p < 0.05); however, no significant difference in potential antioxidant capacity was found. A significant difference was noted in d-ROMs and potential antioxidant capacity during the follicular phase by the effect of time (before and after intake) only in EG (p < 0.01). Significant decreases in d-ROMs and increases in potential antioxidant capacities were observed after intake (p < 0.05). Conclusion: EPA-rich fish oil supplementation over two menstrual cycles demonstrated active involvement in the antioxidant function during menstrual and follicular phases.The protocol was registered at the University Hospital Medical Information Network Clinical Trial Registry (registration no. UMIN000028795).

Effect of Vitamin K-Mediated PXR Activation on Drug-Metabolizing Gene Expression in Human Intestinal Carcinoma LS180 Cell Line.

The pregnane X receptor (PXR) is the key regulator of our defense mechanism against foreign substances such as drugs, dietary nutrients, or environmental pollutants. Because of increased health consciousness, the use of dietary supplements has gradually increased, and most of them can activate PXR. Therefore, an analysis of the interaction between drugs and nutrients is important because altered levels of drug-metabolizing enzymes or transporters can remarkably affect the efficiency of a co-administered drug. In the present study, we analyzed the effect of vitamin K-mediated PXR activation on drug metabolism-related gene expression in intestine-derived LS180 cells via gene expression studies and western blotting analyses. We demonstrated that menaquinone 4 (MK-4), along with other vitamin Ks, including vitamin K1, has the potential to induce MDR1 and CYP3A4 gene expression. We showed that PXR knockdown reversed MK-4-mediated stimulation of these genes, indicating the involvement of PXR in this effect. In addition, we showed that the expression of MDR1 and CYP3A4 genes increased synergistically after 24 h of rifampicin and MK-4 co-treatment. Our study thus elucidates the importance of drug-nutrient interaction mediated via PXR.

4-week eicosapentaenoic acid-rich fish oil supplementation partially protects muscular damage following eccentric contractions.

BACKGROUND: We previously showed 8-week of fish oil supplementation attenuated muscle damage. However, the effect of a shorter period of fish oil supplementation is unclear. The present study investigated the effect of fish oil, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), for 4 weeks on muscular damage caused by eccentric contractions (ECCs) of the elbow flexors. METHODS: Twenty-two untrained men were recruited in this double-blind, placebo-controlled, parallel design study and the subjects were randomly assigned to the EPA and DHA group (EPA and DHA, n = 11) and placebo group (PL, n = 11). They consumed either EPA 600 mg and DHA 260 mg per day or placebo supplement for 4 weeks prior to exercise. Subjects performed 60 ECCs at 100 % maximal voluntary contraction (MVC) using a dumbbell. Changes in MVC torque, range of motion (ROM), upper arm circumference, muscle soreness, echo intensity, muscle thickness, serum creatine kinase (CK), and interleukin-6 (IL-6) were assessed before exercise; immediately after exercise; and 1, 2, 3, and 5 days after exercise. RESULTS: ROM was significantly higher in the EPA and DHA group than in the PL group immediately after performing ECCs (p < 0.05). No differences between groups were observed in terms of MVC torque, upper arm circumference, muscle soreness, echo intensity, and thickness. A significant difference was observed in serum CK 3 days after ECCs (p < 0.05). CONCLUSIONS: We concluded that shorter period EPA and DHA supplementation benefits joint flexibility and protection of muscle fiber following ECCs.