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

Abstract

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.

Keywords: Eicosapentaenoic acid; Ergogenic aid; Joint flexibility; Lengthening; Long‐chain n-3 polyunsaturated fatty acids; Muscle function; Omega-3; Sports nutrition.

Fig. 1

Changes (mean ± SD) of maximal voluntary isometric contraction (MVC) torque at 90° (a), and 110° (b) measured before (pre) and immediately after (post) the eccentric contractions exercise and 1, 2, 3 and 5 days in the placebo (PL) and EPA and DHA groups

Fig. 2

Changes (mean ± SD) of range of motion (ROM) (a), circumference (b), and visual analogue scale (VAS) (c) measured before (pre) and immediately after (post) the eccentric contractions exercise and 1, 2, 3 and 5 days in the PL and EPA and DHA groups. # p < 0.05 for the difference between groups; † p < 0.05 for the difference from the pre-exercise value in the PL group, * p < 0.05 for the difference from pre-exercise value in the EPA and DHA group

Fig. 3

Changes (mean ± SD) of muscle thickness (a) and muscle echo intensity (b) measured before (pre) and immediately after (post) the eccentric contractions exercise and 1, 2, 3 and 5 days in the PL and EPA and DHA groups

Fig. 4

Changes (mean ± SD) of serum creatine kinase (a) and serum interleukin-6 (b) measured before (pre) and the eccentric contractions exercise and 1, 2, 3 and 5 days in the placebo (PL) and EPA and DHA groups. # p < 0.05 for the difference between groups; † p < 0.05 for the difference from the pre-exercise value in the PL group