Prospective, randomized, double-blinded, placebo-controlled study on safety and tolerability of the krill powder product in overweight subjects with moderately elevated blood pressure

Abstract

Background: Krill powder is rich in bioactive ingredients such as eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), phospholipids, protein and astaxanthin. Containing dominantly EPA, it is considered to be effective in lowering lipids, foremost serum triglycerides and LDL cholesterol. Krill-derived protein hydrolysates/peptides may have positive effect on blood pressure and astaxanthin has anti-oxidative and anti-inflammatory properties. Thus, krill powder has a lot of potential in improving lipid and metabolic profile and reinforcing the activity of the antioxidant system. However, randomized clinical trials on krill powder are scarce and systematic data of krill meal on human safety is limited. Some of the earlier studies have reported several, non-serious adverse events, mostly related to gastrointestinal tract, but systematic sufficiently powered study on safety is lacking. The aim of this study was to collect data on safety and tolerability of krill powder in humans and simultaneously gain efficacy data by measuring the risk factors for cardiovascular disease.

Methods: The study was a randomised, double-blinded, placebo-controlled intervention study with 35 overweight subjects with mildly or moderately elevated blood pressure, who took 4 g krill oil powder or 4 g of placebo during an 8-week follow-up period. The study consisted of a pre-screening, screening, day 0 baseline (randomization visit) and three follow-up visits on days 14, 28 and 56. The reported adverse events in the groups were compared as primary endpoint and haematological safety parameters and changes in systolic and diastolic pressure and blood total and lipoprotein lipids were measured as secondary end points.

Results: There were in total 80 reported adverse events during the follow-up; 50 in placebo and 30 in krill powder group. Gastrointestinal symptoms (flatulence, heartburn and diarrhea) were the most commonly reported among those probably related to the test products. No serious adverse events were reported. The mean value of all measured hematology variables remained within the reference values in all study subject and no significant changes were observed in blood pressure or lipid values.

Conclusions: The results seem to indicate that using krill powder as a source for EPA and DHA is safe in therapeutic dose and the risk of adverse events, let alone serious ones, is low.

Trial registration: ClinicalTrials.gov, NCT03112083 , retrospectively registered.

Keywords: Adverse event; Docosahexaenoic acid; Eicosapentaenoic acid; Krill oil; Krill powder; Omega-3 fatty acids; Safety; Tolerability.

Conflict of interest statement

Ethics approval and consent to participate

The trial was approved by the Regional Ethics Committees of the Tampere Hospital District (Tampere) R1511, and conducted according to the Declaration of Helsinki and Good Clinical Practice. Written informed consent was obtained from all subjects before any study related procedures.

Consent for publication

All authors have read the manuscript and approved the publication of it.

Competing interests

IB is partly employed by the study sponsor. The authors declare that they have no competing interests.

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Figures

Fig. 1

Mean diastolic blood pressure (+/-SD) during the intervention in all study subjects (n = 35), krill powder group (n = 17) and placebo group (n = 18)

Fig. 2

Mean systolic blood pressure (+/-SD) during the intervention in all study subjects (n = 35), krill powder group (n = 17) and placebo group (n = 18)