There has been over the last 2-3 years a progressive awareness that another source of essential fatty acids – other than fish and algae, may be useful for supplementing the diet.
Krill oil has attracted food supplement companies and some health care practitioners to consider its use as a replacement for fish oils. A Recent paper in Lipids Health Dis – suggests that there is a difference.[1]
Similar to fish oil, krill oil (KO) is rich in EPA and DHA. However, fatty acids from fish oils are mainly associated with triglycerides (TGs), whereas the n-3 PUFAs in KO are associated with phospholipids (PLs) and TGs. PLs and TGs are digested differently and in turn, this may affect n-3 PUFA bioavailability.[2]
In human studies, feeding infants DHA in PL form resulted in better absorption than feeding DHA in TG form. Determining the digestibility of n-3 PUFAs provided as PL compared to TG is important because this influences n-3 PUFA incorporation into tissues.[3]
Comment
The present study evaluated popular sources of n-3 PUFA as well as krill oil, a novel source of n-3 PUFAs. Higher phospholipid content in krill oil compared to fish oils has led to commercial claims of enhanced digestibility which improves n-3 PUFA tissue deposition and greater oxidative stability.
Based on the results from the study below, rats fed krill oil had lower DHA digestibility and brain incorporation compared to the fish oil sources, salmon oil and tuna oil . Despite krill oil being rich in the antioxidant astaxanthin lipid oxidation was not decreased and gene expression of antioxidant defence enzymes was not increased.
On the other hand, rats fed salmon oil and tuna oil had the highest n-3 PUFAs digestibility and in turn, tissue accretion. Lipid oxidation was not increased in either salmon oil or tuna oil -fed rats despite higher tissue DHA deposition.
On the basis that the optimal n-3 PUFA sources should provide high digestibility and efficient tissue incorporation with the least tissue lipid peroxidation, tuna oil and salmon oil appeared to be the sources of n-3 PUFAs most favourable to health.
What do you think?
References
[1] Tou JC, Altman SN, Gigliotti JC, Benedito VA, Cordonier EL. Different sources of omega-3 polyunsaturated fatty acids affects apparent digestibility, tissue deposition, and tissue oxidative stability in growing female rats. Lipids Health Dis. 2011 Oct 14;10:179. View Full Paper
[2] Gigliotti JC, Davenport M, Beamer S, Tou JC, Jaczynski J. Extraction and characterization of lipids from Antarctic krill (Euphausia superba) Food Chem. 2011;125:1028–1036. doi: 10.1016/j.foodchem.2010.10.013. View Abstract
[3] Innis SM. Dietary omega 3 fatty acids and the developing brain. Brain Res. 2008 Oct 27;1237:35-43. Epub 2008 Sep 9. Review. View Abstract
