Krill oil supports cardiovascular health, study shows

Summary

This randomized, double-blind, placebo-controlled, multi-center trial was designed to investigate the effect of krill oil supplementation on blood triglyceride (TG) and lipoprotein levels in people with borderline high or high blood triglyceride levels and who don’t typical eat fish.

The study was performed at two U.S. clinical research sites in North Dakota and Missouri. To be included, participants had to be between 21 and 79 years of age, have a low habitual fatty fish and seafood intake (i.e., no more than twice per month), and have borderline high or high fasting serum TG levels (i.e., 150-499 mg/dL at screening).

A total of 300 men and women were enrolled in the study and randomly assigned to one of five treatment groups for 12 weeks: placebo (olive oil) or 0.5, 1, 2, or 4 g/day of krill oil. The group assigned one krill oil capsule per day took it with the morning meal, otherwise the krill oil and placebo capsules were distributed evenly between morning and evening doses. The varying doses of krill oil (i.e., 0, 0.5, 1, 2, and 4 g/day) corresponded to daily intakes of EPA + DHA of 0, 100, 200, 400, and 800 mg/day, respectively.

Serum lipids were measured after an overnight fast at baseline, 6 and 12 weeks. Due to a high intra-individual variability in TG levels, data from all participants in the four krill oil groups were pooled to increase statistical power, and a general time- and dose-independent one-way analysis of variance was performed to assess efficacy. (The pooled analysis included all the measurements after 6 and 12 weeks in the 0.5, 1, 2 and 4 g/day krill oil groups compared to placebo).

Three participants dropped out for reasons unrelated to treatment and others had protocol deviations, leaving 267 participants (267/300; 89%) for analysis. No serious adverse effects related to treatment were reported; minor side effects were primarily related to digestive upset.

Results indicate that all doses of krill oil significantly (P<.05) increased the omega-3 index (an emerging indicator of heart health) as early as 6 weeks, compared to placebo. After 6 weeks, participants in the 1, 2 and 4 g/day krill oil groups had a 19-20 mg/dL decrease in fasting serum TG levels, whereas the 0.5 g/day group showed a 13.1 mg/dL decrease, compared to baseline. While the significant change in TG levels was lost at 12 weeks in all groups, participants receiving krill oil still had a 10.2% decrease in fasting serum TG values, as assessed by the pooled analysis. Percent changes in TG levels from baseline in the krill oil groups (−6.3%) were significant (P<.05) compared to those in the placebo group (+3.9%). No significant changes in total, LDL or HDL cholesterol were reported in any group.

These findings suggest krill oil (0.5-4 g/day for 12 weeks) may have clinical value for people with high blood triglycerides.