Can cod liver oil supplementation forestall COVID-19 and different acute respiratory infections?

Many research have been performed to find out therapy choices to fight the coronavirus illness 2019 (COVID-19) pandemic. Important consideration has been given to the position of vitamin D in stopping and treating COVID-19. A number of preclinical research have indicated that vitamin D metabolites play necessary roles in immune responses to respiratory viruses.

Can cod liver oil supplementation forestall COVID-19 and different acute respiratory infections?
Examine: Prevention of covid-19 and different acute respiratory infections with cod liver oil supplementation, a low dose vitamin D complement: quadruple blinded, randomised placebo managed trial. Picture Credit score: Iryna Pohrebna/Shutterstock

Furthermore, low ranges of 25-hydroxyvitamin D3 (25(OH)D3) have been noticed to extend the danger of acute respiratory infections. A current meta-analysis prompt that vitamin D supplementation might cut back the danger of respiratory infections in comparison with a placebo.

Critical circumstances of COVID-19 have been related to uncontrolled activation of immune cells, elevated irritation, and extreme launch of proinflammatory cytokines. Lengthy-chain omega-3 fatty acids akin to docosahexaenoic acid and eicosapentaenoic acid have been discovered to own anti-inflammatory properties. Subsequently, making certain adequate ranges of vitamin D and these fatty acids can function an economical method to forestall critical COVID-19 in addition to SARS-CoV-2 infections.

Cod liver oil is a low-dose vitamin D complement comprising docosahexaenoic acid and eicosapentaenoic acid. Taking cod liver oil throughout winter is a protracted custom in Norway to forestall vitamin D deficiency.

A brand new research revealed within the British Medical Journal (BMJ) aimed to investigate whether or not cod liver oil might forestall critical COVID-19, SARS-CoV-2 an infection, or different acute respiratory infections through the winter of 2020-2021.

In regards to the research

The research was a parallel group therapy, randomized, two-armed, and quadruple masked trial consisting of individuals who had been 18 years of age and above, had a Norwegian private identification quantity, in addition to entry to the safe nationwide digital governmental identification service. Randomization of individuals happened in a 1:1 ratio to take placebo or cod liver oil with a each day dodge of 5 ml. Each the placebo and cod liver oil underwent blind testing by an skilled style panel who had been unable to differentiate between the 2.

Randomization was carried out with out stratification or blocking on the Division of Analysis Assist, Oslo College Hospital. The gathering, storage, and evaluation of information had been additionally carried out by The College of Oslo.

Individuals had been required to finish baseline questionnaires that included questions on private information, vitamin D, and others earlier than they acquired both the placebo or cod liver oil. They had been adopted up after six months on compliance with the intervention, SARS-CoV-2 an infection, COVID-19 vaccination, acute respiratory infections, and expertise of any unwanted side effects.

Compliance was described as strict if greater than 5ml of placebo or cod liver oil was taken for greater than 2 to three months. Compliance was described as free if greater than 1 ml of placebo or cod liver oil was taken for a few month or taken greater than someday per week. The unwanted side effects had been graded and categorized as per the Widespread Terminology Standards for Hostile Occasions (CTCAE).

An evaluation of 4 co-primary endpoints was carried out. The primary was a constructive SARS-CoV-2 oropharyngeal or nasopharyngeal swab take a look at detected by reverse transcriptase quantitative polymerase chain response at a Norwegian lab and reported to the Necessary Norwegian Surveillance System for Communicable Ailments (MSIS). The second endpoint was the incidence of great COVID-19 that was related to admission to the hospital or demise. The third endpoint was the incidence of individuals with a number of damaging SARS-CoV-2 take a look at outcomes recorded in MSIS. The fourth endpoint was the incidence of individuals who reported a number of acute respiratory infections.

The variety of individuals admitted to the hospital or intensive care unit for COVID-19 comprised the predefined secondary endpoint. Exploratory endpoints comprised self-reported modifications in blood ranges of 25(OH)D3 and omega 3 index, blinding of the research complement, and unwanted side effects. Blood samples had been collected from the individuals earlier than and through supplementation for evaluation of the degrees of omega-3 fatty acids and 25(OH)D3. Lastly, SARS-CoV-2 antibody evaluation was carried out at baseline.

Examine findings

The outcomes indicated {that a} complete of 34,741 individuals had been included within the research, the place greater than half of the individuals had been ladies, had a imply age of 44.9 years, and had a physique mass index of 26.1 at baseline. Seventeen thousand 200 seventy-eight individuals got cod liver oil, whereas 17,323 got the placebo.

Many of the individuals reported not utilizing any vitamin D supplementation earlier than the research, whereas 39.8% reported about 30 hours of solar publicity from July to October 2020, and 61.5% reported consumption of fatty fish. Furthermore, 35.6% had been discovered to have acquired a number of doses of a COVID-19 vaccine.

A complete of 455 individuals reported a constructive SARS-CoV-2 take a look at consequence with equal distribution between the place and cod liver oil teams. Critical COVID-19 was reported by 101 individuals within the placebo group and 121 individuals within the cod liver oil group. A complete of 17 individuals had been hospitalized, out of which eight had been within the intensive care unit. Furthermore, the relative threat of great COVID-19 was noticed to be 1.20 for the cod liver oil group in comparison with the placebo group.

Moreover, 17,111 individuals had been discovered to point out a number of damaging SARS-CoV-2 take a look at outcomes whose distribution was comparable in each the teams, whereas 7,798 individuals reported a number of acute respiratory infections. Evaluation of blood samples revealed solely barely elevated concentrations of 25(OH)D3 within the cod liver oil group in comparison with the placebo group. The imply focus of 25(OH)D3 was discovered to be elevated by 15.0 nmol/L, whereas the omega-3 index was elevated by 1.9%.

Eleven level 3 % and 10.1% of individuals within the placebo and cod liver oil group, respectively, reported a number of unwanted side effects, with delicate gastrointestinal signs belonging to CTCAE grade 1 being the commonest aspect impact. Grade 2 unwanted side effects had been extra usually noticed within the placebo group. Lastly, 7616 individuals within the placebo group and 7220 within the cod liver group didn’t know which supplementation they had been taking or believed to take the placebo, whereas 1,058 within the placebo group and 1,966 within the cod liver oil group believed to take the cod liver oil supplementation.

Subsequently, the present research demonstrated {that a} low dose supplementation of vitamin D together with docosahexaenoic acid and eicosapentaenoic acid for six months was not appropriate for stopping SARS-CoV-2 infections, critical COVID-19, and different acute respiratory infections. Nonetheless, the consumption of this supplementation produced solely low-grade unwanted side effects.


The present research has sure limitations. First, self-reported end-point information might introduce bias. Second, the intervention time was comparatively brief, and the longer results of cod liver oil couldn’t be evaluated. Third, the consequences of vitamin D and omega-3 fatty acids couldn’t be distinguished. Fourth, the impact of vitamin D on the danger of SARS-CoV-2 couldn’t be evaluated in the beginning of the trial. Lastly, the variety of individuals included within the trial was decrease than the anticipated quantity.

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