Omega-3 fatty acids and exercise: a review of their combined effects on body composition and physical performance

Today's summary is about a non-CS paper written in 2011.

1. Omega-3 (n-3) fatty acids, and the long-chain n-3 de­rivatives eicosapentaenoic acid (EPA) and docosahexa­enoic acid (DHA) in particular, have been extensively researched for their nutritive effects.
2. n-3 acids have been impli­cated as positive mediators of cardiovascular health and body composition.
3. Initial interest in the cardiovascular benefits of EPA and DHA was aroused by the finding that the Greenland Eskimos and other populations who consume diets rich in these fatty acids have exceedingly low incidences of cardiovascular diseases.
4. Fish oil contains a high amount of n-3 acids.
5. EPA and DHA, the longer chain of n-3 fatty acids, are found in various cold-water fish including salmon, mackerel, sardines, and herring.
6. ALA (α-lino­lenic acid), the shortest chain form of n-3, is found in various plant sources such as flaxseeds, soybeans, and walnuts.
7. Despite a wealth of research on the health-related benefits of n-3 acids, studies investigating the effects of combining n-3 supplementation and exercise are limited. Summary of existing studies:
   • Hyperlipi­demic subjects were assigned to fish oil + exercise, fish oil, corn oil, and control groups. After 12 weeks, only the fish oil + exercise group lost significant body fat. However, the study had no exercise-only control group.
   • Healthy sedentary male subjects were assigned to fish oil + exercise, fish oil, exercise, and control groups. After 10 weeks, no significant differences in body com­position were noted between any of the groups studied. However, the fairly low initial body fat levels in participants may have limited the results.
   • Overweight subjects assigned to either fish oil + exercise, sunflower oil + exercise, fish oil, or sunflower oil groups. After 12 weeks, the fish oil + exercise group had a sig­nificantly greater reduction in body fat compared to an equal dose of sunflower oil + exercise.
   • Overweight and obese subjects were assigned to receive either capsules containing EPA & DHA or a placebo. Both groups exercised. After 24 weeks, both groups lost about 5% of their fat without any significant difference between groups.
8. At this time, research is largely inconclusive as to the potential synergistic benefits when n-3 is supple­mented in conjunction with exercise. There is some evidence that n-3 can modestly enhance lipolysis and β­oxidation during exercise and thereby improve fat loss. There also is modest evidence that n-3 supplementation may help to improve various aspects of exercise perfor­mance. However, limitations in study design make it difficult to draw firm conclusions on these topics.
9. Finally, it is possible that n-3 may improve weight loss during exercise by helping to regulate appetite.
10. However, high consumption of n-3 can lead to immunosuppression and prolong bleeding time