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Why people associate krill with shrimps is because our mind works in generalising information which probably makes it easier to recall later... So when you look at this picture below you might be thinking..."krill sure looks like a shrimp!" but in reality it would be like comparing an ape to a monkeys uncle...
While krill and shrimp are both crustaceans due to their soft shell and beady eyes, but their differences are quite distinct in terms of body structure and composition and other characteristics. Let me further explain the differences below.
1. Habitat
Firstly, Antarctic Krill are a kind of zooplankton that lives in the pristine waters of Antarctica, while shrimp live in many places in every continent except in Antarctica (3). Krill feed on mostly phytoplankton (algae) from under sheets of ice while shrimps are usually scavengers and will eat most organic matter. Krill are specially evolved in handling the harsh subzero temperatures and still thrive.
2. Lifespan
Krill are able to live up to 10 years which is a surprisingly long time for a tiny zooplankton. Krill live submerged deep in the ocean hiding from predators and come out at night to feed. Shrimps have a lifespan of up to 1-6 years.
3. Harvesting
As krill are easily perishable, harvesting them to extract and preserve its nutritive qualities has been a conundrum that has baffled scientists and experts for years, not to mention a very high cost venture. There is also no krill farming as all krill is caught wild. Harvesting shrimp on the other hand is relatively simple with ample supply of both wild and farmed shrimp.
4. Nutritional value
One of the most important differences are the nutritional differences. Krill has higher extractable lipids, and is a potent source of Omega-3 (35.8 - 47.0%) which has higher absorption into the plasma and brain due to its rich phospholipid (PL) content (1).
Shrimps are also nutritious and a good source of iodine, but its fatty acid composition is highly dependant on the source (wild or farmed) and diet with significantly higher Omega-3 (24.08%) in wild shrimp compared to (16.52%) in farmed species. See table below (1)
% | PL (PC,PE,PI) | Omega-3 | Omega-6 | EPA | DHA |
Krill | 2.0 - 6.0 | 35.8 - 47.0 | 2.73 - 3.12 | 20.61 - 28.2 | 14.0 |
Shrimp /Prawn | 1.3 | 11.0 - 28.0 | 2.1 - 39.0 | 0.61 - 13.4 | 1.18 - 14.9 |
5. Krill is higher in antioxidants
Krill naturally contain high levels of bioactive lipids i.e Phospholipids and Omega-3, along with traces of a carotenoid Astaxanthin and vitamin E. While Krill and Shrimps are both a source of Astaxanthin, which the highest levels are found in the shells. Shrimps also have lower levels of extractable bioactive lipids compared to krill.
6. Krill is lower in Omega-6
Another important difference is that shrimps also contain high levels of Omega-6 compared to krill. Omega-6 can cause low grade inflammation and form bad cholesterol which is positively associated with coronary artery disease (CAD), whereas Omega-3 is inversely related to CAD (2).
7. Supplement form (Concentrated)
I wanted to save the best for last. As krill is extracted into a concentrated oral dosage form which gives it the therapeutic effects for heart, brain, liver & eye health and can be taken conveniently as a supplement. For BioRed Krill Oil we are able to push up the levels of total lipids to > 93% and Omega-3 to >33% with highest purity of Phosphatidylcholine up to 95.5% for best effects.
Summary
So while shrimp and krill may look the same, but they are quite different in nature. There are also many proven health benefits relating to krill oil so look our for more of these similar updates soon.
References:-
1. Ahmmed MK, Ahmmed F, Tian H, Carne A, Bekhit AE. Marine omega-3 (n-3) Phospholipids: A Com- prehensive Review of their Properties, Sources, Bioavailability, and Relation to Brain Health.Compr Rev Food Sci Food Saf. 2020;19:64–123.https://doi.org/10.1111/1541-4337.12510
2. Hodgson JM , Wahlqvist ML , Boxall JA , et al. Can linoleic acid contribute to coronary artery disease?Am J Clin Nutr1993;58:228–34.doi:10.1093/ajcn/58.2.228
3. S. De Grave; Y. Cai; A. Anker (2008). Estelle Virginia Balian; C. Lévêque; H. Segers; K. Martens (eds.). "Global diversity of shrimps (Crustacea: Decapoda: Caridea) in freshwater". Hydrobiologia. Springer. 595 (1: Freshwater Animal Diversity Assessment): 287–293. doi:10.1007/s10750-007-9024-2. ISBN978-1-4020-8258-0. S2CID22945163.