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Krill oil supports metabolic health, study shows


  • Krill oil significantly reduces the plasma level of 2-AG 
  • 2-AG is an endocannabinoid that strongly correlates with metabolic health
  • Effective dosage is 2 g/day for 4 weeks


This randomized, double-blind, placebo-controlled pilot study was designed to evaluate the effect of krill oil on levels of two plasma endocannabinoids — 2-arachidonoylglycerol (2-AG) and anandamide (AEA) — in normal, overweight and obese adults.

The authors note that it is well established that the plasma level of 2-AG in obese individuals strongly correlates with several parameters of the metabolic syndrome, including visceral adipose tissue, high triglyceride levels, low HDL-cholesterol levels and indices of insulin resistance.

For this study, 63 overweight or obese, but otherwise healthy, men and women, 35 to 64 years of age, were randomly assigned to one of three treatments providing 2 g/day of either krill oil (providing 216 mg/day EPA and 90 mg/day DHA), menhaden oil (providing 212 mg/day EPA and 178 mg/day DHA), or olive oil (control) for 4 weeks. Treatments were provided in four capsules per day, and subjects were encouraged to take 2 capsules with each of two meals. Participants were stratified based on body mass index (BMI): normal weight (BMI less than 25 kg/m2), overweight (BMI 25-29.9), and obese (BMI 30-35).

The study included 3 visits: screening, baseline and end of treatment. At baseline, obese participants had significantly (P<.05) higher plasma AEA levels and overweight participants had significantly (P<.05) higher plasma 2-AG levels compared to normal weight participants.

Results indicate that krill oil significantly (P<.05) decreased the plasma level of 2-AG, but not AEA, in obese participants after 4 weeks of treatment. (A non-statistically significant decrease in 2-AG was reported in overweight subjects.) By contrast, menhaden oil and olive oil had no significant effect in any group.

Interestingly, a significant (P<.05) correlation between the 2-AG level and the ratio of omega-6 to omega-3 phospholipids in plasma was reported in obese participants who supplemented with krill oil. No other correlation was found between endocannabinoids and single plasma phospholipid fatty acids, or in normal and overweight patients. No changes in BMI, waist circumference, glycemia and insulinemia were reported with any treatments.

These preliminary findings suggest krill oil helps normalize the endocannabinoid system in obese adults, which may offer therapeutic value for treatment of metabolic syndrome.


Banni S, Carta G, Murru E, et al. Krill oil significantly decreases 2-arachidonoylglycerol plasma levels in obese subjects. Nutr Metab. 2011;8(1):7.

PMID: 21276269