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Thursday, April 21, 2016

21/04/2016: Why whole fish is better than oil extracts?

by Ioannis Zabetakis

First published in International Aquafeed, March-April 2016


There are an increasing number of papers and reports suggesting that the nutritional value of whole fish is higher than the one of fish oil extracts. This is a rather interesting area for aquaculture and pharmaceutical industries, since many neutraceutical and pharmaceutical products, claiming that they are good sources of Omega-3 and Omega-6 fatty acids, are in fact extracts. Are these products really efficient in protecting us against the onset of cardiovascular diseases (CVDs)?

https://issuu.com/international_aquafeed/docs/iaf1602_w1/4
Image: Gloria Cabada-Leman
Given that “theory guides, experiment decides”, we decided to compare head to head a whole fish to an oil extract. We chose sardines and cod liver oil. So the aim of our study was to compare the biological activities of polar lipids of sardine fillets and cod liver oil against atherogenesis.

The total polar lipids of these two sources were extracted and fractionated by TLC and these fractions were assessed for their ability to inhibit the platelet-activating-factor (PAF)-induced platelet aggregation (PAF-antagonists) or to induce platelet aggregation (PAF-agonists), since PAF plays a crucial role in the initiation and development of atherosclerosis.

We chose to focus on the polar lipids since previous studies have underlined that the antithrombotic properties of foodstuffs are mainly attributed to polar lipid micro-constituents.

We found that sardine fillet polar lipids induced platelet aggregation, while the polar lipids of cod liver oil had a bimodal effect on platelets. Overall, sardine polar lipid fractions showed stronger in vitro antithrombotic activities than the cod liver oil ones. It could be thus suggested that for the prevention of CVDs, the nutritional value of whole sardines is rather higher than the one of cod liver oil.
 
https://issuu.com/international_aquafeed/docs/iaf1602_w1/4
Image: Neil Tackaberry
It should be also highlighted that sardines lipids were found to consist of about 58 percent polar lipids as opposed to cod liver oil that contained only 1 percent of polar lipids. This data suggests that in the manufacturing process of cod liver oil as it is carried out today by leading pharmaceutical manufacturers, the polar lipids of oils are not extracted and this has rather important negative effect on the nutritional value of the final extract in relation to the prevention of CVDs.

We would suggest that the extraction and purification industrial processes should be re-evaluated with the view to obtain a final extract richer in polar lipids.

ioannis.zabetakis@ul.ie
@yanzabet     

Read the magazine HERE
  


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