Safety and Tolerability of Krill Powder Supplement in Slightly Overweight People With Moderately Elevated Blood Pressure

Krill powder is a food supplement rich in active ingredients such as fatty acids, phospholipids, protein and antioxidants like astaxanthin. It is considered to be more effective in lowering triglyceride values than fish oils and it may have positive effect on cholesterol values as well. Krill proteins 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 values and having other positive health effects on cardiovascular system. However, there haven't been many clinical studies done with krill powder and thus systematic data on human safety is limited.

The aim of this study was to systematically collect data on safety and tolerability of krill powder in humans and simultaneously gain efficacy data by measuring the risk factors for cardiovascular disease.

The study was a randomised, double-blinded, placebo-controlled intervention study with slightly obese subjects with mildly or moderately elevated blood pressure. Study was conducted at two study sites in Central (Tampere) and Northern Finland (Oulu). In total 35 subjects were randomised according to randomisation list to two groups (krill powder or placebo) in a balanced manner (1:1), separately for both gender and site. Concealed allocation was used to keep both subjects and staff blinded. The study consisted of a pre-screening, Day -7-(-14) screening visit, Day 0 baseline (Randomization visit) and 8-week safety and tolerance follow-up period with three follow-up visits on Day 14, Day 28 and Day 56.

A total of 6 study visits were included. At pre-screening visit the study subjects were requested to sign pre-screening visit informed consent form. A structured interview on demographics (age, sex, ethnicity), previous and current diseases, current medication, alcohol and tobacco consumption and use of dietary supplements (especially fish oil and other n-3 fatty acid (FA) supplements, plant sterols and cholesterol lowering fiber supplements (guar gum, glucomannan, oat fiber etc.) and use of fish foods was carried out at the screening visit and replicated at the day 56 visit. Study included one test product: krill powder derived from antarctic krill (Euphausia Superba) (Rimfrost Pristine®, Rimfrost AS, PO box 234, 6099 Fosnavaag, Norway) and placebo product and both were given in capsule form, 4 capsules in the morning and 4 in the evening.

Nutritional counselling regarding the consumption of fish, omega-3 and -6 fatty acids, food supplements and investigational product for the duration of the study were given for the study subjects at the screening visit by a study nurse or registered dietitian and compliance was followed throughout the study. The subjects were advised to keep their medication, lifestyle, background diet and body weight constant during the study and deviation were recorded into the diary.

As a primary endpoint of the study, the total number of reported adverse events were compared in the study subject groups taking 8 capsules (4 g) krill oil powder or 8 capsules (4 g) of placebo for the 8-week follow-up period. Any unfavourable and unintended sign, symptom or medical complaint and worsening of a pre-existing condition was regarded as adverse event (AE). Study subjects kept diary for the whole duration of the study and were requested to write down all unfavourable symptoms and medical complaints not existing at baseline or significantly worsened from baseline situation. Completeness of diaries was checked at each study visit. All reported adverse events were recorded, coded and analysed carefully to determine severity, possible relation to study products, onset and outcome of the event. In addition, safety laboratory values, cholesterol and triglyceride values and blood pressure was measured.