Temporal changes in human skeletal muscle and blood lipid composition with fish oil supplementation.
Level 4 - case-series / case-control
Prospective single-arm pre-post study with an internal run-in control period and no randomized comparator group.
PubMed 24726616 · doi:10.1016/j.plefa.2014.03.001
What was done
Ten healthy male participants completed a 2-week internal control run-in period followed by 4 weeks of supplementation with 5 g/day of fish oil. Fasting venous blood samples and skeletal muscle biopsies were collected 2 weeks prior to baseline (W-2), at baseline (W0), and at weeks 1 (W1), 2 (W2), and 4 (W4) of supplementation to measure lipid profiles and total protein content of focal adhesion kinase (FAK) and mechanistic target of rapamycin (mTOR).
What was found
No numerical values, percentages, or effect sizes were reported in the abstract. Qualitatively, lipid composition did not change between W-2 and W0. Following supplementation, blood n-3 PUFA levels increased by W1 and remained elevated through W4, whereas skeletal muscle n-3 PUFA levels increased significantly by W2 and continued rising through W4. Total muscle FAK protein content increased from W0 to W4, while total mTOR protein content increased from W0 to W1 without further significant increases at W2 and W4.
Why it matters
It demonstrates that omega-3 fatty acid incorporation into human skeletal muscle lags behind blood lipid enrichment and provides preliminary evidence that fish oil supplementation can alter baseline muscle anabolic signalling protein abundance.
Limits
The study had a very small sample size (n=10) restricted entirely to healthy young men. There was no randomized parallel control group to rule out time-dependent or biopsy-induced confounding, and specific numerical results, dietary background, and functional anabolic outcomes (such as muscle protein synthesis rates) were not provided in the abstract.
Cited by
- supports Approximately four weeks of high-dose omega-3 supplementation is required to see a substantial increase in the omega-3 profile of human skeletal muscle.