A randomized, parallel-group treatment, quadruple masked, two-arm study to assess the effectiveness of cod liver oil compared to placebo in the prevention of Covid-19 and airway infections in healthy adults. In this study, the investigators will investigate whether daily cod liver oil can prevent Covid-19 infections and reduce the severity of such infections. The investigators will also examine whether cod liver oil prevents other airway infections in healthy adults.
Preliminary evidence from literature and an ongoing study in the investigators' lab suggests
that cod liver oil may prevent Covid-19 and complications of Covid-19. In the present study,
the investigators will examine whether this is actually the case by randomizing volunteers to
take cod liver oil or placebo (corn oil) during the winter months of 2020-2021. The
investigators also aim to explore whether cod liver oil can prevent other respiratory tract
infections, as well as explore and confirm already known health effects and possible new
health effects, in particular rare adverse events associated with cod liver oil use.
Cod liver oil is a traditional source of vitamin A, D, and E and omega-3 fatty acids and the
dose administered in the study will contain 250 ug vitamin A, 10 ug vitamin D, 10 mg vitamin
E, and 1,2 g omega-3 fatty acids.
Dietary Supplement: Cod liver oil
5 ml of cod liver oil as a source of 10 ug of vitamin D and 1.2 g of long-chained n-3 polyunsaturated fatty acids (DHA 0,6g and EPA 0,4g) per day for 6 months x 1 time/day together with the first meal of the day. 5ml of Cod liver oil also contains 250ug vitamin A and 10 mg vitamin E.
Other Name: Array
Dietary Supplement: Corn oil (placebo)
5 ml of corn oil per day for 6 months x 1 time/day together with the first meal of the day
Inclusion Criteria:
- Any person >18 years with a Norwegian Personal Identity Number
Exclusion Criteria:
- History of renal failure or dialysis, hypercalcemia, severe liver disease (cirrhosis),
sarcoidosis or other granulomatous diseases (Wegener)
- Allergy to fish or corn oil.
- Pregnancy or planned pregnancy before summer 2021
- Vegan diet
- Age >75 years old at inclusion based on the Norwegian Personal Identity Number
- Difficulty in swallowing cod liver oil or other oils
- Previous Covid-19 disease
- For Caucasians only: Use of any supplement containing more than trace amounts of
vitamin D or omega-3 fatty acids at inclusion (Vitamin D levels in non-Caucasians
living in Norway are frequently low even among those self-reporting using dietary
supplements). This criterion will be relaxed if too few participants volunteer for the
study and only Caucasians that use cod liver oil or an equivalent dietary supplement
(with omega 3 and vitamin D) more than 5-7 times per week will be excluded.
Oslo University Hospital
Oslo, Norway
Arne Søraas, MD, PhD, Principal Investigator
Oslo University Hospital