|If you listened to the SuppVersity Science News Round Up on Super Human Radio, yesterday, you may remember that the color of food can tell you something about it's antioxidant activity... well, guess what: It's the lipid-soluble pigment and potent antioxidant astaxanthin that gives krill its "healthy" orange-red color.|
Moreover, the results of a 2011 study by Burri et al. (Burri. 2011), which showed that other than fish oil, krill oil with an equimolar amount of EPA and DHA in it actally decreased the expression of those hepatic genes for gluconeogenesis and glycolysis which could be responsible for the problematic increase in glucose levels Poudyal et al. observed in response to high dose omega-3 supplementation (yesterday's news). Now, these observations certainly raise the question:
Can we ward off the negatives and maximize the benefits by using krill instead of fish?
|You can't eat krill? Fraser Lewry's recipe for krill fried rice looks very real (and delicous) to me|
Now, while we will come back to the question of "eating whole krill" later, let's initially take a closer look a the experiment Bjorndal et al. conducted. The scientists two groups of particularly inflammation prone transgenic male mice of a C57BL/6 strain which constitutively expresses high TNFα (tumor necrosis factor-alpha aka cachexin, or cachectin) levels iso-caloric "high fat" diets. Half of the animals were randomized to the notorious high carbohydrate + high fat diet you usually see in studies like these, the other had parts of the protein and fats replaced with the protein and fat from krill powder (see figure 1 for more details).
|Figure 1: The composition of the experimental diets (Bjørndal. 2012).|
"The liver of mice fed the krill powder diet displayed increased β-oxidation, reduced lipogenesis, and reduced cholesterol- and glucose metabolism compared to high-fat fed mice, resulting in improved plasma and hepatic lipid levels." (Bjørndal. 2012)In short, the provision of the krill based lipid + protein mixture affected the lipid metabolism, the expression of genes involved in glucose metabolism and the fatty acid composition in plasma and liver of the animals, while keeping the mitochondrial respiratory electron transport chain in liver intact.
How come this sh*t doesn't work?
With the increased energy expenditure from fat in response to both krill and fish oil, comes a lower reliance on glucose as a fuel source. Therefore, more of the sugary glue that makes an excellent fuel, but a very bad lubricant, will remain floating around in the blood, so that the unquestionably impressive >50% reduction of hepatic glyocogen breakdown and the corresponding -45% reduction in gluconeogenesis (see figure 2, green hexagons) are probably just enough to compensate the decreased glucose oxidation, so that the overall amount of glucose that's floating around freely in the blood of the krill oil / or powder supplemented animals will remain the same (with fish oil, and in the absence of these epigenetic changes, it will even go up!).
Bottom Line: While krill powder appears to have the edge over plain fish oil, it's use is yet likewise no panacea for all the ailments of the metabolic syndrome.
The impressive amino acid composition of the protein fraction in krill powder (see information box on the right), as well as Yamada et al.'s 2011 observation that an obviously fat-free, since water soluble krill extract directly antagonizes triglyceride accumulation (=increase in fat content) in adipocytes by suppressing PPARγ and C/EBPα expression (Yamada . 2011), still speak in favor of my initial hypothesis that there is more healthy stuff in krill (and fish) than EPA, DHA & the rest of the omega-3 fatty acid megillah, so to say.
- Bjørndal B, Vik R, Brattelid T, Vigerust NF, Burri L, Bohov P, Nygård O, Skorve J, Berge RK. Krill powder increases liver lipid catabolism and reduces glucose mobilization in tumor necrosis factor-alpha transgenic mice fed a high-fat diet. Metabolism. 2012 Oct;61(10):1461-72.
- Burri L, Berge K, Wibrand K, Berge RK, Barger JL. Differential effects of krill oil and fish oil on the hepatic transcriptome in mice. Front Genet. 2011;2:45. Epub 2011 Jul 12.
- Gigliotti JC, Jaczynski J, Tou JC. Determination of the nutritional value, protein quality and safety of krillprotein concentrate isolated using an isoelectric solubilization/precipitation technique Food Chemistry, Volume 111, Issue 1, 1 November 2008, Pages 209–214.
- Rossmeisl M, Macek Jilkova Z, Kuda O, Jelenik T, Medrikova D, Stankova B, Kristinsson B, Haraldsson GG, Svensen H, Stoknes I, Sjövall P, Magnusson Y, Balvers MG, Verhoeckx KC, Tvrzicka E, Bryhn M, Kopecky J. Metabolic Effects of n-3 PUFA as Phospholipids Are Superior to Triglycerides in Mice Fed a High-Fat Diet: Possible Role of Endocannabinoids. PLoS One. 2012;7(6):e38834. Epub 2012 Jun 11.
- Sindayikengera S, Xia WS. Nutritional evaluation of caseins and whey proteins and their hydrolysates from Protamex. J Zhejiang Univ Sci B. 2006 Feb;7(2):90-8.
- Yamada H, Ueda T, Yano A. Water-soluble extract of Pacific Krill prevents triglyceride accumulation in adipocytes by suppressing PPARγ and C/EBPα expression. PLoS One. 2011;6(7):e21952.