Inflated astaxanthin numbers abound
Why does our krill oil appear to have less astaxanthin than some brands?
This happens for three reasons.
Reason #1 - Using "esterified astaxanthin" doses
Most makers express the astaxanthin content of their krill oil as the weight of the astaxanthin molecules plus the weight of the fatty acid esters (fat molecules) – mostly omega-3s – to which they are naturally attached.
But in general, the weight of astaxanthin plus its fatty acid ester "package" is double the weight of the pure, active astaxanthin molecule, called the "astaxanthin diol".
This explains why the stated astaxanthin content of some krill oil brands appears about twice as much as ours.
Astaxanthin diol is completely de-esterified (stripped of its accompanying fatty acid esters) in the gut before absorption.
Scientists agree that the most honest way to express the astaxanthin content of krill oil is to cite the weight of the diol, or "diol equivalent".
For example, in 2011, the Australian government's Advisory Committee on Complementary Medicines said* that manufacturers should express the astaxanthin content of krill as the astaxanthin diol equivalent, instead of the commonly used esterified astaxanthin number. As they said, the diol number for astaxanthin is "a more analytically valid parameter."
*Australian Advisory Committee on Complementary Medicines. 18 April 2011. Accessed at http://www.tga.gov.au/about/accm-recommendations-2010-04.htm
Reason #2 - Using "astaxanthin complex" doses
Instead of (or in addition to) the misleading practice of reporting a dose-per-serving based on esterified astaxanthin, some brands present an astaxanthin dose per serving that's based on "astaxanthin complex".
This is misleading because, in addition to pure astaxanthin (astaxanthin diol), the term "astaxanthin complex" encompasses other carotenoids such as beta carotene, canthaxanthin, and lutein, which are naturally present in the Haematococcus algae from which virtually all astaxanthin is extracted.
These other carotenoids can represent as much as 15% of the total carotenoids in these brands' supplements ... which means that reporting the weight of a supplement's "astaxanthin complex" overstates the amount of pure astaxanthin (astaxanthin diol) present by about 18%.
Reason #3 - Added astaxanthin
Based on the unnaturally high levels of astaxanthin they claim for their krill oil, we believe that some makers add astaxanthin to their krill to boost the claimed amount.
However, as common sense would suggest, there is little to no evidence that astaxanthin provides any significant health benefits at the minuscule levels found in krill oil: Less than 500 parts per million (i.e., less than 500 micrograms per gram).
Instead, the real benefit of the astaxanthin in krill oil is to provide antioxidant protection to the oil itself, keeping it fresh much longer than vitamin E could, for example.