"As there is now general guidance to the population in the UK and elsewhere to increase the dietary intake of omega – 3 fatty acids, either by increased consumption of oily fish or by use of fish oil supplements, these results suggest that the pre-emulsification of these supplemental fish oils would significantly improve their absorption," wrote lead author Iveta Garaiova from Obsidian Research, who sponsored the research.
The healthy reputation of omega-3 fatty acids, particularly EPA and DHA has exploded into consumer consciousness, based largely on evidence that it can aid cognitive function, may help protect the heart against cardiovascular disease, and could reduce the risk of certain cancers.
Such advice has seen the number of omega-3 enriched or fortified products on the market increase.
According to new research pre-esterification of an omega-3-containing oil mixture before consumption increased the absorption of the longer chain unsaturated fatty acids EPA and DHA, without affected the absorption of shorter chain less saturated fatty acids.
Writing in the Nutrition Journal , Garaiova said the result suggests "that pre-emulsification of fish oils may be a useful means of boosting absorption of these beneficial fatty acids."
Twenty-four people (average age 35, average BMI 24.66 kg per sq m, 14 women) were randomly assigned to receive either emulsified oil or un-emulsified oil (43 per cent fish oil, 31 per cent borage oil, 26 per cent flaxseed oil) as part of a fat-free meal.
The oils were supplied by Cultech, UK.
Garaiova and her collaborators from Cardiff University, the London School of Hygiene & Tropical Medicine and Cultech, took blood samples from the volunteers every 90 minutes for nine hours.
A 20-day washout period followed and then the volunteers were crossed over to the other intervention.
The researchers report that postprandial (after-meal) triacylglycerol (TAG)and the long-chain omega-3 concentrations in the blood increased significantly after consumption of the emulsified oil, relative to the non-emulsified oil.
Indeed, non-emulsification reduced EPA and DHA absorption by 33.6 and 44.3 per cent, respectively.
On the other hand, no significant changes between the oils were observed for the absorption of saturated fatty acids and monounsaturated fatty acids.
"The study… shows that pre-emulsification of an oil mixture increases the absorption of the longer chain more highly unsaturated fatty acids especially EPA and DHA, but not of the shorter chain less unsaturated fatty acids," wrote the researchers.
They suggested that several factors may be behind the improvement in absorption of the omega-3 fatty acids by emulsification.
"This includes the nature of the test meal and background diet, the influence of droplet size of the oil emulsion, the inherent resistance of longer chain fatty acids, especially EPA and DHA, to pancreatic lipase and the delay in the enterocyte re-synthesis of TAG," they said.
Source: Nutrition Journal 2007, 6 :4, doi:10.1186/1475-2891-6-4 "A randomised cross-over trial in healthy adults indicating improved absorption of omega-3 fatty acids by pre-emulsification" Authors: I. Garaiova, I.A. Guschina, S.F. Plummer, J. Tang, D. Wang and N.T. Plummer