Ascenta

Thank you for your comments regarding krill oil absorption and astaxanthin. In the case of claims made within the natural products industry clinical studies are often misinterpreted or aspects taken out of context.

Krill oil absorption

With the limited studies available the absorption of krill vs fish would be concluded as equal. Since the absorption of fish oil in TG form has been determined to be between 75-85% it would theoretically be impossible to have something else be absorbed 500% better as claimed by many krill oil brands. See my comments on the 2 available published studies on absorption:

Ulven SM, Kirkhus B, Lamglait A, Basu S, Elind E, Haider T, Berge K, Vik H, Pedersen JI. (2011). Metabolic Effects of Krill Oil are Essentially Similar to Those of Fish Oil but at Lower Dose of EPA and DHA, in Healthy Volunteers. Lipids, 46:37-46.

Healthy subjects supplemented with krill oil containing 37.2% less EPA+DHA than those supplemented with fish oil (TG) saw same increases in plasma EPA and DHA over the seven week treatment period. This study indicates that EPA and DHA from krill oil are equally, or possible more, bioavailable than those from fish oil. This could be due to krill oil’s higher content of EPA and DHA in the PL form.

However, it is interesting to note that the subjects in the krill oil treatment group were given almost twice as much oil compared to the fish oil group; 3g (6 capsules) of krill oil and 1.8g (3 capsules) of fish oil.

Maki KC, Reeves MS, Farmer M, Griinari M, Berge K, Vik H, Hubacher R, Rains TM. (2009). Krill oil supplementation increases plasma concentrations of eicosapentaenoic and docosahexaenoic acids in overweight and obese men and women. Nutritional Research, 29;609-615.

Overweight and obese subjects were supplemented with 2g of either krill oil (216 mg EPA and 90 mg DHA), fish oil (212 mg EPA and 178 DHA) or control (olive oil) for 4 wks. At the end of the study, subjects receiving krill oil or fish oil had statistically significant plasma elevations of EPA and DHA compared to the control group. However, the increase in plasma EPA and DHA levels were not significantly different between the krill oil and fish oil groups.  Even though subjects in the krill oil group had higher plasma levels of EPA compared to the fish oil group, this difference was not statistically different. This indicates krill oil is absorbed as well as fish oil.

Astaxanthin

Although there are studies that support the comment of Astaxanthin being an effective antioxidant there are studies that found conflicting results. Studies conducted in soybean oil found that astaxanthin provides superior protection against photo-oxidation compared to lutein, lycopene, zeaxanthin and isozeaxanthin (Lee et al., 1990). Another study investigated the effectiveness of various carotenoids to scavenge phenoxyl radicals (Mortensen & Skibsted, 1997). They found that lycopene was most reactive with phenoxyl radicals while astaxanthin was not reactive at all (Mortensen & Skibsted, 1997). Woodall et al. (1997) found that lycopene, Beta-carotene and zeaxanthin were all more reactive with various oxidizing agents than astaxanthin. The more reactive the carotenoid is to a radical, the less likely radicals will be available to react with other molecules in a system (i.e. unsaturated fatty acids), thus Woodall et al.’s findings agree with Mortensen and Skibted (1997). Thus, a few in vitro studies looking at the antioxidant mechanism carotenoids, indicate that astaxanthin may not be as potent an antioxidant as other carotenoids, especially lycopene.

References:

Lee SH, Min DB. (1990). Effects, quenching mechanisms, and kinetics of carotenoids in chlorophyll-sensitized photooxidation of soybean oil. Journal of agricultural and food chemistry, 38:1630-1634.

Mortensen A, Skibsted LH. (1997). Importance of carotenoid structure in radical-scavenging reactions. J. Agric. Food Chem., 45:2970-2977.

Woodall AA, Lee SWM,  Weesie RJ, Jackson MJ, Britton. (1997). Oxidation of carotenoids by free radicals: relationship between structure and reactivity. Biochimica et Biophysica Acta, 1336: 33-42.

The vast array of questions and comments re: krill oil sustainability is indicative of the challenges scientists have in researching such species. One scientist was quoted recently as saying, “Counting krill stock status is like counting trees in a forest except the trees are always moving.” Knowing the challenges of such research and the often conflicting data available, Ascenta uses a precautionary approach to sourcing raw materials.

Sandra, thanks for your comments on krill sustainability.  You certainly have a more in-depth knowledge than most concerning krill issues. The particular facts you've shared are often cited by krill suppliers and don't represent the views of the scientific community.  The truth is that the krill fishery is difficult to assess and with the best available data, scientists are pushing to establish significant reform to the krill fishery before irreparable damage is done to this fragile eco-system. Perhaps down the road we'll have better data and regulations to create a sustainable krill fishery.  Until then, we have to take the right course of action and protect the Antarctic region. Here are some additional science based resources that address the issues and concerns with the krill fishery: 

  http://www.assoc.org/issues-and-advocacy/krill-conservation

  http://www.krillcount.org/issues.html