Krill reside in the pristine, frigid waters of the Antarctic Ocean. They are near the bottom of the food chain and contain relatively low amounts of fat. Thus metal and contaminant uptake and content is expected to be minimized. Actual testing of the krill oil used in MegaRed for heavy metals, pesticides, dioxins and halogenated biphenyls (PCBs) has found undetectable or extremely low levels of these compounds. Thus, there is no fear of contamination with krill oil, unlike fish and fish oil. Schiff Nutrition International routinely conducts heavy metal testing on every batch of MegaRed krill oil using sensitive ICP/MS equipment. Thus, consumers can be assured that MegaRed does not have issues with contamination that have been a concern for other omega-3 fatty acid sources.

Overall and heavy metal safety was investigated in a fish farming setting by Moren et al. (Moren 2006). Atlantic salmon were fed krill meal in place of their usual cod fish meal. As the sole or major source of dietary intake for a well-characterized and sensitive biological system (growing salmon) intended for human consumption, krill meal did not adversely affect growth rates or health of farmed fish.

Safety of omega-3 phospholipids have been investigated in another very sensitive population – infants. Extensive investigations on infant formulas with omega-3 enriched egg phospholipids in animal and human infants have not found adverse effects, and have been approved worldwide for addition to infant formulas by food safety agencies. In a more detailed and specific study on krill oil, Ruggiero-Lopez et al. investigated the effect of krill oil on intestinal fucosylation at weaning in baby rats (Ruggiero-Lopez 1994). Intestinal fucosylation is a sensitive marker of intestinal development and safety in growing infants. Krill oil diets were very well tolerated compared to other commonly used oil.

In the human clinical study by Maki et al., 2000 mg krill oil daily for four weeks was not associated with adverse side effects compared to the placebo group (Maki 2009). Also, there was no change in objective safety measures such as blood chemistries, insulin levels, HOMA-IR, F2-isoprostanes or vital signs except for a modest decline in systolic blood pressure (a known benefit from omega-3 fatty acids). The authors concluded:

Other unpublished human clinical studies on the krill oil used in MegaRed at doses up to 4000 mg daily for weeks or months have not found evidence of adverse side effects (Aker Biomarine, unpublished data).

 
Allergy Information

Krill oil is extracted from krill, which are closely related to shrimp. The muscle proteins of krill are tropomyosin, very similar to shrimp (Motoyama 2008, Nakano 2008). Tropomyosin has been identified as an allergen in shrimp and related shellfish and crustaceans (Leung 1996, Motoyama 2008, Nakano 2008, Reese 1999, Shanti 1993). Krill tropomyosin has been shown to cross-react to human sera with IgE antibodies to shrimp tropomyosin (Motoyama 2008, Nakano 2008). There is potential for krill protein to be reactive in individuals with shrimp/shellfish allergies. Thus, MegaRed contains a WARNING stating that persons with seafood allergy should notify their physician and be tested for allergic reactions prior to taking MegaRed.

The protein content of krill oil is not zero, but is very low. Anecdotally, some individuals with known (and minor) allergic reactions to shrimp have not reacted to typical serving sizes of MegaRed. However, trace amounts of krill protein are present in MegaRed, and health care professionals should address this issue in their patients that are known or suspected to have shellfish allergies.

 
Interactions

Krill oil contains omega-3 fatty acids EPA + DHA as the major active components. However, because the overall dose of omega-3 fatty acids is low compared to eating fish and typical doses of fish oil supplements, the chance for interactions or adverse events from krill oil at recommended serving sizes is minimized. Even accounting for the more efficient absorption and targeting of omega-3 fatty acids into cell membranes, the dose is still too low to trigger interactions or interferences, according to the fish and fish oil literature. In addition, in assessing the application for the Health Claim on EPA and DHA omega-3 fatty acids and cardiovascular disease risk, the US FDA found that coagulation problems should not arise with a dose of less than 3000 mg EPA + DHA per day (Lewis 2000). In other words, the amount of omega-3 fatty acids in krill oil and MegaRed recommended and clinically tested serving sizes are well within safe dietary intakes.

Nevertheless, on MegaRed bottle labels and boxes, there is language in the WARNING statement that individuals with coagulopathy, taking anticoagulant medications or other medications should contact their physician before taking this supplement. These statements are commonly found on products containing omega-3 fatty acids so that consumers and health care professionals are aware and notified of possible interactions.

Schiff Nutrition International always notifies consumers with CAUTION and WARNING statements on product labels and packaging to notify their physicians about what dietary supplements they are taking. Also, pregnant or nursing consumers are instructed to consult their health care professional before using a dietary supplement.