Comparison of the effects of fish and fish-oil capsules on the n 3 fatty acid content of blood cells and plasma phospholipids.
Level 2 - randomized trial
Individual randomized controlled trial
PubMed 18065578 · doi:10.1093/ajcn/86.5.1621
What was done
Healthy premenopausal female volunteers were randomized to receive a daily average of 485 mg EPA and DHA from either two servings of oily fish (salmon and albacore tuna) per week or 1–2 fish-oil capsules per day for 16 weeks. The rate and extent of EPA and DHA enrichment in red blood cell (RBC) membranes and plasma phospholipids were compared between the two groups.
What was found
After 16 weeks, RBC EPA+DHA increased from 4.0 ± 0.6% to 6.2 ± 1.4% in the fish group (n = 11) and from 4.3 ± 1.0% to 6.2 ± 1.4% in the capsule group (P < 0.0001 for both within-group increases; not significant for group effect). Similar results occurred in plasma phospholipids, which stabilized at 4 weeks, whereas RBC levels increased through week 16. RBC EPA increased significantly faster in the fish group during the first 4 weeks (P = 0.01), with no significant group difference in rate thereafter. Total fatty acid variances were lower in RBCs than in plasma phospholipids (P = 0.04).
Why it matters
This study shows that consuming EPA and DHA through weekly dietary fish is as bioavailable and effective for tissue fatty acid enrichment as taking daily fish-oil supplements.
Limits
The total sample size is small (fish group n = 11; capsule group n not stated in the abstract). The study included only healthy premenopausal females, limiting direct generalization to other populations, and dietary interventions cannot be blinded.
Cited by
- supports A serving of salmon provides about 1.5 grams of omega-3 fatty acids.