Is krill or other marine oil better than fish oil?

The fish oil supplement business is a multi-billion dollar a year industry. With such a lucrative and well established market, it's easy to see why supplement companies clamour to offer consumers other marine oil alternatives. Claims of higher potency, bioavailability and fast absorption for various other marine oils are touted all to gain a slice of the fish oil supplement consumer dollar.

So what is the catch? Which marine oil is best?

The debate between fish and other marine oils such as krill oil requires that you cast a net far and wide in order to reel in all of the available scientific literature.

As with anything, the devil is in the detail. Sure there may be one or two studies that appear to show some benefits but when we take a closer look we realize:

• Most supplement studies are very short duration (48-72 hours) and use few participants, only 8-12.

• Measures of absorption are often taken from plasma concentrations. These measures are used to assume bioavailability.

Plasma concentrations do not equal tissue concentrations. Few marine oil studies actually show how much make it to the target tissue.

Other factors can also affect absorption and bioavailability such as variation among populations, individuals from one day to the next, from one dose to the next. Co-ingestion of the supplement with other macro-nutrients can all affect (inhibit or enhance) absorption.

Even if the absorption rate and bioavailability of other marine oils were equal to that of fish oil the cost alone is often prohibitive. Fish oil usually costs $0.07-$0.11 per milligram while the cost of krill oil may be between $0.49 to $0.69 per milligram.

That's five times the cost, at least. Add that over a lifetime.

The bottom line is, may be a few studies show some small advantages for other marine oils such as krill, but over all, none have been shown to provide a clear benefit over fish oil and definitely none are as cost effective. 

References:

Schuchardt J. Hahn A. Bioavailability of long-chain omega-3 fatty acids. Prostaglandins, Leukotrienes and Essential Fatty Acids. 

Colquhoun D. Reeve A. Krill Oil Claims: Fact or Fiction? Heart, Lung and Circulation.

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