Bioavailability of fatty acids from krill oil, krill meal and fish oil in healthy subjects–a randomized, single-dose, cross-over trial

Abstract

BackgroundKrill contains two marine omega-3 polyunsaturated fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), mainly bound in phospholipids. Typical products from krill are krill oil and krill meal. Fish oils contain EPA and DHA predominantly bound in triglycerides. The difference in the chemical binding of EPA and DHA has been suggested to affect their bioavailability, but little is known on bioavailability of EPA and DHA in krill meal.This study was undertaken to compare the acute bioavailability of two krill products, krill oil and krill meal, with fish oil in healthy subjects.MethodsA randomized, single-dose, single-blind, cross-over, active-reference trial was conducted in 15 subjects, who ingested krill oil, krill meal and fish oil, each containing approx. 1 700 mg EPA and DHA. Fatty acid compositions of plasma triglycerides and phospholipids were measured repeatedly for 72 hours. The primary efficacy analysis was based on the 72 hour incremental area under the curve (iAUC) of EPA and DHA in plasma phospholipid fatty acids.ResultsA larger iAUC for EPA and DHA in plasma phospholipid fatty acids was detected after krill oil (mean 89.08 ± 33.36% × h) than after krill meal (mean 44.97 ± 18.07% x h, p < 0.001) or after fish oil (mean 59.15 ± 22.22% × h, p=0.003). Mean iAUC’s after krill meal and after fish oil were not different. A large inter-individual variability in response was observed.ConclusionEPA and DHA in krill oil had a higher 72-hour bioavailability than in krill meal or fish oil. Our finding that bioavailabilities of EPA and DHA in krill meal and fish oil were not different argues against the interpretation that phospholipids are better absorbed than triglycerides. Longer-term studies using a parameter reflecting tissue fatty acid composition, like erythrocyte EPA plus DHA are needed.Trial registrationNCT02089165

Bioavailability of Dietary Omega-3 Fatty Acids Added to a Variety of Sausages in Healthy Individuals

“…Earlier, we demonstrated variability of bioavailability of EPA and DHA as a triglyceride in a convenience drink by a factor of 13 inter-individually [20]. In the meantime, however, this has been confirmed by us, and others [47,67]. While predicting a mean dose-response of the Omega-3 Index to supplementation with EPA and DHA in a population using complicated statistical models is possible, such prediction is basically impossible for an individual [20,47,67].…”

Omega-3 polyunsaturated fatty acid supplementation and white matter changes in major depression

“…Dietary absorption might be affected by different formulations of omega-3 PUFAs, e.g. the bioavailability of triglyceride-associated PUFAs predominant in fish oil is reportedly lower than phosphoglyceride-associated PUFAs in as in krill oil (92). However, krill meal, which also contains DHA and EPA bound to phospholipids, has similar bioavailability to fish oil, suggesting the triglyceride-phospholipid difference may not be the main arbiter of absorption (92).…”

“…the bioavailability of triglyceride-associated PUFAs predominant in fish oil is reportedly lower than phosphoglyceride-associated PUFAs in as in krill oil (92). However, krill meal, which also contains DHA and EPA bound to phospholipids, has similar bioavailability to fish oil, suggesting the triglyceride-phospholipid difference may not be the main arbiter of absorption (92). Free (unesterified) fatty acids also have been suggested to have superior bioavailability (93) but are a target for oxidation that may result in breakdown and in gastrointestinal side-effects (94).…”

Influence of lipid type on gastrointestinal fate of oil-in-water emulsions: In vitro digestion study

“…These results clearly show that phospholipid-rich krill oil behaves quite differently from other triacylglycerol-rich oils under simulated stomach conditions, which may have important implications for its gastrointestinal fate. Indeed, in vivo studies have reported higher bioavailability of omega-3 fatty acids when delivered as krill oil rather than as fish oil, which was partly attributed to the fact that the polyunsaturated fatty acids were part of phospholipids in krill oil(Kohler, Sarkkinen, Tapola, Niskanen, & Bruheim, 2015;Schuchardt et al, 2011). Conversely, other in vivo studies have reported a higher bioavailability of polyunsaturated fats from fish oils than from krill oil(Tou, Altman, Gigliotti, Benedito, & Cordonier, 2011).…”