Effect of ingesting fish oil on serum lipid and lipoprotein concentration in exercising and nonexercising women

The purpose of this study was to determine the effects of ingesting a fish oil supplement, taking exercise with a fish oil supplement, or taking exercise alone on serum lipid and lipoprotein fractions in premenopausal and postmenopausal women during a 12‐week period. Premenopausal (n = 30) and postmenopausal (n = 30) subjects were randomly assigned to one of three groups: exercise, exercise and fish oil, and fish oil only. Both exercise groups attended an exercise session twice weekly for 12 weeks. A control group (n = 10) followed their normal habitual lifestyle for the same period. Group 3 (fish oil) were required to ingest one fish oil capsule daily, which contained 171 mg eicosapentanoic acid and 114 mg of docosahexanoic acid. Serum lipid and lipoprotein concentrations were determined in venous blood (12‐hour fasted) at baseline and at four intervals of 1 week in all subjects. Body fatness was determined by near infrared interactance. Premenopausal subjects demonstrated a significantly lower mean (± SD) total serum cholesterol concentration than the postmenopausal subjects (5.39 ± 0.23 and 6.22 ± 0.31 mmo.L1, respectively), and there was a significant treatment by test interaction (p ≤ 0.05). The premenopausal group taking fish oil recorded a significant decrease in mean (± SD) total serum cholesterol concentrations during the experimental period (4.11 ± 0.95 to 3.65 ± 0.87) mmol.L1). There was no change in serum high density lipoprotein concentration in any group. Both treatment groups recorded a mean (± SD) fall in serum low density lipoprotein concentrations during the period of the investigation (4.02 ± 0.58 to 3.71 ± 0.25 mmol.L1) and there was a treatment by status by test interaction (p ≤ 0.05). There was no change in serum triglyceride concentration in any group, but there was a significant decrease in body fatness between the values at 12 weeks and at baseline in both the exercise and the exercise and fish oil supplement groups (exercise group at 12 weeks was 31.2 ± 2.6%; baseline was 33.1 ± 2.4% body fat; exercise and fish oil group at 12 weeks was 30.25 ± 2.8)%; baseline was 31.7 ± 3.2% body fat).