Prevention of covid-19 and other acute respiratory infections with cod liver oil supplementation, a low dose vitamin D supplement: quadruple blinded, randomised placebo controlled trial
BMJ 2022; 378 doi: https://doi.org/10.1136/bmj-2022-071245
Sonja H Brunvoll, postdoctoral researcher1, Anders B Nygaard, postdoctoral researcher1, Merete Ellingjord-Dale, postdoctoral researcher1, Petter Holland, postdoctoral researcher1, Mette Stausland Istre, research engineer1, Karl Trygve Kalleberg, chief executive officer2, Camilla L Søraas, junior doctor3, Kirsten B Holven, professor4 5, Stine M Ulven, professor4, Anette Hjartåker, professor4, Trond Haider, senior statistician6, Fridtjof Lund-Johansen, senior scientist7, John Arne Dahl, group leader1, Haakon E Meyer, professor8 9, Arne Søraas, principal investigator1
Objective To determine if daily supplementation with cod liver oil, a low dose vitamin D supplement, in winter, prevents SARS-CoV-2 infection, serious covid-19, or other acute respiratory infections in adults in Norway.
Design Quadruple blinded, randomised placebo controlled trial.
Setting Norway, 10 November 2020 to 2 June 2021.
Participants 34 601 adults (aged 18-75 years), not taking daily vitamin D supplements.
Intervention 5 mL/day of cod liver oil (10 µg of vitamin D, n=17 278) or placebo (n=17 323) for up to six months.
Main outcome measures Four co-primary endpoints were predefined: the first was a positive SARS-CoV-2 test result determined by reverse transcriptase-quantitative polymerase chain reaction and the second was serious covid-19, defined as self-reported dyspnoea, admission to hospital, or death. Other acute respiratory infections were indicated by the third and fourth co-primary endpoints: a negative SARS-CoV-2 test result and self-reported symptoms. Side effects related to the supplementation were self-reported. The fallback method was used to handle multiple comparisons.
Results Supplementation with cod liver oil was not associated with a reduced risk of any of the co-primary endpoints. Participants took the supplement (cod liver oil or placebo) for a median of 164 days, and 227 (1.31%) participants in the cod liver oil group and 228 (1.32%) participants in the placebo group had a positive SARS-CoV-2 test result (relative risk 1.00, multiple comparison adjusted confidence interval 0.82 to 1.22). Serious covid-19 was identified in 121 (0.70%) participants in the cod liver oil group and in 101 (0.58%) participants in the placebo group (1.20, 0.87 to 1.65). 8546 (49.46%) and 8565 (49.44%) participants in the cod liver oil and placebo groups, respectively, had ≥1 negative SARS-CoV-2 test results (1.00, 0.97 to 1.04). 3964 (22.94%) and 3834 (22.13%) participants in the cod liver oil and placebo groups, respectively, reported ≥1 acute respiratory infections (1.04, 0.97 to 1.11). Only low grade side effects were reported in the cod liver oil and placebo groups.
Conclusion Supplementation with cod liver oil in the winter did not reduce the incidence of SARS-CoV-2 infection, serious covid-19, or other acute respiratory infections compared with placebo.
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Vitamin D Life pages with RESPIRATORY in title (79 as of Sept 2022)
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Items found: 81
| Title | | Modified |
| 40 cents of Vitamin D given once during pregnancy reduced respiratory problems by 3% – May 2023 | | 28 Feb, 2024 |
| COVID Vaccinated Children 1.25 X More Likely to Be Hospitalized for Respiratory Illness - CDC Jan 2024 | | 12 Jan, 2024 |
| Respiratory infection, children and Vitamin D - many studies | | 08 Oct, 2023 |
| Acute respiratory tract infections not reduced by Vitamin D if already have a good level – Jan 2021 | | 30 Sep, 2023 |
| Respiratory infections in children 6 X more likely if low Vitamin D (avg of 2 studies) - Aug 2023 | | 22 Aug, 2023 |
| Respiratory infections reduced by 63 percent with 4000 IU vitamin D daily - RCT Dec 2012 | | 17 Jul, 2023 |
| 3% fewer respiratory problems in children if single 100K vitamin D in 3rd trimester – May 2023 | | 27 May, 2023 |
| Cost-effective to give Vitamin D to all children to prevent acute respiratory infection – April 2023 | | 09 Apr, 2023 |
| The vitamins and minerals that help the immune system respond to respiratory viruses – Dec 2022 | | 06 Dec, 2022 |
| Respiratory viral infection (RSV) and low vitamin D - many studies | | 18 Nov, 2022 |
| Cod liver oil does not prevent Respiratory Infections (no surprise, only 400 IU of vitamin D) RCT – Sept 2022 | | 08 Sep, 2022 |
| Calcifediol (semi-activated Vitamin D) might treat Respiratory Diseases such as COVID - July 2022 | | 19 Jul, 2022 |
| 2.4 X fewer lower respiratory track infections in infants getting 400 IU of Vitamin D – May 2022 | | 24 May, 2022 |
| Small doses of vitamin D do not reduce risk of Acute Respiratory Infection - meta-analysis Feb 2022 | | 15 Feb, 2022 |
| Viral respiratory infections reduced by both Vitamin D and Zinc – meta-analysis -Oct 2021 | | 11 Oct, 2021 |
| Acute viral respiratory infections (RTI) reduced by Vitamin D - 20 reviews - Aug 2020 | | 24 Sep, 2021 |
| Respiratory Tract Infections during cold weather – similar rates for low and very low vitamin D – Sept 2021 | | 24 Sep, 2021 |
| Infant Respiratory Infections not reduced by mothers taking small amount of vitamin D (28,000 weekly)– RCT July 2021 | | 03 Jul, 2021 |
| Vitamin D may reduce Respiratory Tract Infections and the use of antibiotics – March 2021 | | 24 Jun, 2021 |
| Vitamin D reduces Respiratory Tract Infections and reduces use of antibiotics – March 2021 | | 15 Apr, 2021 |
| Small vitamin D doses provide small benefits for acute respiratory infections – Meta-analysis March 2021 | | 31 Mar, 2021 |
| Vitamin D reduces viral respiratory infections – editorial April 18, 2020 | | 02 Mar, 2021 |
| Respiratory Tract Infection risk reduced 2X by Vitamin D loading doses – meta-analysis Jan 2021 | | 22 Jan, 2021 |
| Preemie Respiratory Distress Syndrome is 5X more likely if low vitamin D – Dec 2020 | | 18 Dec, 2020 |
| Upper Respiratory Tract Infections in adults reduced by just 400 IU of vitamin D – RCT Dec 2020 | | 12 Dec, 2020 |
| Respiratory deaths in seniors – 40 percent are attributable to low vitamin D – Aug 2020 | | 18 Aug, 2020 |
| Respiratory problems in Children 1.4X more likely if poor Vitamin D receptor – April 2020 | | 22 Jul, 2020 |
| Reasons why some Respiratory Allergy studies find that Vitamin D does not help much – June 2020 | | 21 Jun, 2020 |
| Zinc, respiratory tract infections and COVID-19 – July 2020 | | 07 Jun, 2020 |
| Lower Respiratory Tract Infection in Infants reduced 5.9 X by daily 600 IU of vitamin D (China) - March 2020 | | 07 Mar, 2020 |
| Four of the 7 types of human Coronavirus only cause mild respiratory infections | | 04 Feb, 2020 |
| Respiratory Disease exacerbations (Asthma, CF, COPD) may be treated by Vitamin D – July 2019 | | 26 Nov, 2019 |
| No preemie had even 30 ng of vitamin D, lower D associated with more Respiratory Distress – Aug 2013 | | 24 Jul, 2019 |
| Acute respiratory distress – 100 percent of patients were vitamin D deficient– April 2015 | | 09 Jun, 2019 |
| Upper respiratory infection associated with poor Vitamin D Receptor – Oct 2018 | | 16 Feb, 2019 |
| Respiratory Distress Syndrome in preemies 5 X more likely if poor vitamin D receptor – Feb 2019 | | 15 Feb, 2019 |
| Respiratory infections reduced only 20 percent by Vitamin D (ignored dose size, duration, type, etc) – meta-analysis Jan 2019 | | 25 Jan, 2019 |
| Upper respiratory infection 15 percent more likely if poor Vitamin D receptor– Oct 2018 | | 09 Dec, 2018 |
| Low vitamin D at ICU admission is associated with cancer, infections, acute respiratory insufficiency and liver failure – Oct 2018 | | 27 Oct, 2018 |
| Respiratory Virus risk reduced 35 percent by Vitamin D (14,000 IU weekly) – RCT Oct 2018 | | 18 Oct, 2018 |
| Respiratory disase rate increase 3X after remove tonsils - June 2018 | | 08 Jul, 2018 |
| Respiratory tract microbiome and breathing problems | | 18 Jun, 2018 |
| Childhood Respiratory Health hardly improved with 600 IU of vitamin D (need much more) – May 2018 | | 28 May, 2018 |
| Pollutants increase Respiratory problems, Vitamin D, Omega-3, etc. decrease them – May 2018 | | 05 May, 2018 |
| Respiratory Tract Infections in children 7.4 X more likely if poor Vitamin D Receptor – 2008 | | 11 Feb, 2018 |
| Preemies with poor lungs (Respiratory distress syndrome) have low levels of vitamin D – Nov 2017 | | 14 Nov, 2017 |
| Respiratory infection in infant was 7 X more likely if low cord Vitamin D – March 2017 | | 28 Sep, 2017 |
| Acute respiratory tract infections prevented by vitamin D (even when ignoring the dose size – Meta-analysis Feb 2017 | | 09 Aug, 2017 |
| Vitamin D in respiratory diseases – Spring 2017 | | 09 Apr, 2017 |
| The relationship between Vitamin D and the respiratory system remains inconclusive – Jan 2016 | | 06 Mar, 2017 |
| Fewer respiratory infections if optimal level of vitamin D (more than 47 ng) – Sept 2013 | | 03 Mar, 2017 |
| Vitamin D effects on lung immunity and respiratory diseases – 2011 | | 29 Jan, 2017 |
| Respiratory tract infection eliminated in 36 percent of people by 4000 IU of Vitamin D – RCT Sept 2015 | | 13 Jan, 2017 |
| Monthly 100,000 IU of vitamin D decreased respiratory infection but increased falls – Nov 2016 | | 10 Dec, 2016 |
| Acute Lower Respiratory Infections in Children - associated with low vitamin D – meta-analysis Dec 2014 | | 16 Sep, 2016 |
| Immune response to respiratory viruses – vitamin D connection – review May 2015 | | 17 May, 2016 |
| Lower respiratory tract infections in children associated with Low Vitamin D – meta-analysis May 2016 | | 15 May, 2016 |
| Acute respiratory infection treated by vitamin D in 6 of 12 clinical trials – review Nov 2012 | | 15 May, 2016 |
| Respiratory tract infections in childhood – vitamin D is needed, no consensus of how much – Oct 2015 | | 15 May, 2016 |
| Acute respiratory infection worsened by too infrequent vitamin D supplementation – RCT June 2015 | | 17 Dec, 2015 |
| Respiratory diseases helped by vitamin D if initially have low level – RCT review Jan 2015 | | 13 Oct, 2015 |
| Respiratory distress after preterm birth is more likely if low vitamin D – review April 2015 | | 05 Aug, 2015 |
| Respiratory infections (RTI) cut in half by 20,000 IU weekly vitamin D if initially deficient – RCT March 2015 | | 18 Apr, 2015 |
| Respiratory Infection associated with vitamin D less than 40 ng – March 2015 | | 18 Apr, 2015 |
| Low dose Vitamin D during pregnancy and infancy results in strange acute respiratory infection response – April 2015 | | 24 Mar, 2015 |
| Vitamin D and Respiratory Tract Infections – meta-analysis with charts June 2013 | | 24 Mar, 2015 |
| Acute lower respiratory infection 5X more frequent with low vitamin D intake – June 2012 | | 20 Mar, 2015 |
| Newborn acute lower respiratory tract infection associated with low maternal vitamin D – March 2015 | | 20 Mar, 2015 |
| Reduced viral respiratory tract infections by half by having more than 38 ng of vitamin D – June 2010 | | 29 Oct, 2014 |
| Acute Lower Respiratory Infections in Children: 13 of 18 studies found associations with low vitamin D – meta-analysis Dec 2014 | | 23 Oct, 2014 |
| Respiratory Tract Infection visits 2.5 less likely with vitamin D: Pregnancy 2000 IU, Infant 800 IU – RCT Oct 2014 | | 04 Oct, 2014 |
| Far fewer lower respiratory tract infections at 36 months if good vitamin D during pregnancy – Nov 2013 | | 18 Jul, 2014 |
| Respiratory viral infections might be prevented by vitamin D supplementation in those with low vitamin D – Sept 2014 | | 18 Jul, 2014 |
| Upper respiratory tract infection 2X more likely if vitamin D less than 30 ng – Aug 2013 | | 12 Feb, 2014 |
| Vitamin D reduces respiratory tract infections by 40 percent– meta-analysis Dec 2012 | | 28 Oct, 2013 |
| Vitamin D and respiratory tract infections - Wikipedia June 2013 | | 29 Jun, 2013 |
| Largest cause of infant deaths is respiratory infections, which is associated with low vitamin D – April 2011 | | 23 Jun, 2013 |
| 100 percent of Acute Respiratory Failure patients had low vitamin D - April 2012 | | 21 Jun, 2013 |
| Low vitamin D associated with respiratory, digestive, and other deaths – Dec 2012 | | 04 Jan, 2013 |
| Hypothesis: Respiratory problems will decrease with increased vitamin D – Jan 2012 | | 02 Dec, 2012 |
| Just 300 IU daily of vitamin D reduced respiratory infections by 50% – RCT Aug 2012 | | 25 Aug, 2012 |