Response to commentary on a trial comparing krill oil versus fish oil

Vanu R Ramprasath,Peter Jh Jones,Sigalit Zchut,Inbal Eyal

doi:10.1186/1476-511x-13-17

Abstract

Nichols et al. (Lipids Health Dis13:2, 2014) raised concern about the higher n-6 concentration in fish oil used in our recent study which is different from typical commercial fish oils (Ramprasath et al. Lipids Health Dis12:178, 2013). The aim of our study was to compare the effect of consumption of similar amount of n-3 PUFA from krill and fish oil with placebo on plasma and RBC fatty acids. As the concentration of n-3 PUFA in the fish oil utilised was higher than that in krill oil, we deemed it important to keep consistent the concentration of n-3 PUFA and volumes to be administered to participants between krill versus fish oils. As such, the fish oil used in the study was diluted with corn oil. Although the n-6 PUFA concentration in fish oil was higher compared to traditionally used fish oil, consumption of the fish oil used in our study actually reduced the total n-6 PUFA in plasma and RBC to a similar extent as did krill oil. Overall, our conclusion was that the increases in plasma and RBC concentrations of EPA and DHA along with improvement in the omega-3 index observed with consumption of krill oil compared with fish oil are due to differences in absorption and bioavailability based on the structural difference of the two oils rather than their n-6 PUFA content.

Highlights

Recently, Ramprasath et al [1] compared effects of consumption of 600 mg/day of n-3 Polyunsaturated fatty acids (PUFA) from krill or fish oil versus placebo corn oil by healthy individuals for 4 weeks separated by 8 week wash out periods using a double blind randomised cross over study design
Nichols et al [2] raised an issue regarding reported fatty acid profile of fish oil used in that it possessed high concentrations of n-6 PUFA. This assessment did not take into consideration that the n-3 PUFA concentrations of krill and fish oils are not similar and the concentration of n-3 PUFA between the two oils needed to be adjusted for consistency
Dietary n-6 PUFA consumption by the participants was not controlled during the study

Summary

Introduction

Ramprasath et al [1] compared effects of consumption of 600 mg/day of n-3 PUFA from krill or fish oil versus placebo corn oil by healthy individuals for 4 weeks separated by 8 week wash out periods using a double blind randomised cross over study design. Results showed increased plasma and RBC n-3 PUFA concentrations after consumption of n-3PUFA from the krill compared to fish oil. Nichols et al [2] raised an issue regarding reported fatty acid profile of fish oil used in that it possessed high concentrations of n-6 PUFA This assessment did not take into consideration that the n-3 PUFA concentrations of krill and fish oils are not similar and the concentration of n-3 PUFA between the two oils needed to be adjusted for consistency

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