title: Incorporation of EPA and DHA into plasma phospholipids in response to different omega-3 fatty acid formulations--a comparative bioavailability study of fish oil vs. krill oil.
abstract: BACKGROUND
  Bioavailability of omega-3 fatty acids (FA) depends on their chemical form. Superior bioavailability has been suggested for phospholipid (PL) bound omega-3 FA in krill oil, but identical doses of different chemical forms have not been compared.
  
  
  METHODS
  In a double-blinded crossover trial, we compared the uptake of three EPA+DHA formulations derived from fish oil (re-esterified triacylglycerides [rTAG], ethyl-esters [EE]) and krill oil (mainly PL). Changes of the FA compositions in plasma PL were used as a proxy for bioavailability. Twelve healthy young men (mean age 31 y) were randomized to 1680 mg EPA+DHA given either as rTAG, EE or krill oil. FA levels in plasma PL were analyzed pre-dose and 2, 4, 6, 8, 24, 48, and 72 h after capsule ingestion. Additionally, the proportion of free EPA and DHA in the applied supplements was analyzed.
  
  
  RESULTS
  The highest incorporation of EPA+DHA into plasma PL was provoked by krill oil (mean AUC0-72 h: 80.03 ± 34.71%*h), followed by fish oil rTAG (mean AUC0-72 h: 59.78 ± 36.75%*h) and EE (mean AUC0-72 h: 47.53 ± 38.42%*h). Due to high standard deviation values, there were no significant differences for DHA and the sum of EPA+DHA levels between the three treatments. However, a trend (p = 0.057) was observed for the differences in EPA bioavailability. Statistical pair-wise group comparison's revealed a trend (p = 0.086) between rTAG and krill oil. FA analysis of the supplements showed that the krill oil sample contained 22% of the total EPA amount as free EPA and 21% of the total DHA amount as free DHA, while the two fish oil samples did not contain any free FA.
  
  
  CONCLUSIONS
  Further studies with a larger sample size carried out over a longer period are needed to substantiate our findings and to determine differences in EPA+DHA bioavailability between three common chemical forms of LC n-3 FA (rTAG, EE and krill oil). The unexpected high content of free EPA and DHA in krill oil, which might have a significant influence on the availability of EPA+DHA from krill oil, should be investigated in more depth and taken into consideration in future trials.
authors.affiliation: Institute of Food Science and Human Nutrition, Leibniz University Hannover, Germany. schuchardt@nutrition.uni-hannover.de
authors.forename: Jan Philipp
authors.initials: JP
authors.lastname: Schuchardt
authors.forename: Inga
authors.initials: I
authors.lastname: Schneider
authors.forename: Henrike
authors.initials: H
authors.lastname: Meyer
authors.forename: Juliane
authors.initials: J
authors.lastname: Neubronner
authors.forename: Clemens
authors.initials: C
authors.lastname: von Schacky
authors.forename: Andreas
authors.initials: A
authors.lastname: Hahn
mesh_terms: D000328:Adult; D000818:Animals; D019540:Area Under Curve; D002626:Chemistry, Pharmaceutical; D004281:Docosahexaenoic Acids / Q000493:pharmacokinetics*; D004311:Double-Blind Method; D015118:Eicosapentaenoic Acid / Q000493:pharmacokinetics*; D033201:Euphausiacea; D005395:Fish Oils / Q000493:pharmacokinetics*; D006801:Humans; D008297:Male; D010743:Phospholipids / Q000097:blood*
chemical_list: D005395:Fish Oils; D010743:Phospholipids; D004281:Docosahexaenoic Acids; D015118:Eicosapentaenoic Acid