Recent paper in the BMJ concluded that vitamin D supplementation is not of benefit to prevent COVID-19. In this video, the research is reviewed with the aim to clarify important points around vitamin D supplementation.
The UK study also found no significant differences in "severity of acute covid-19 or prolonged symptoms of covid-19...between those randomized to either the lower or the higher dose offer group compared with the no offer group." For example, 1.4% of the no-supplement control group was admitted to the hospital for COVID, compared to 1.6% of those receiving 800 IU, and 1.9% those receiving 3200 IU.
Jolliffe, David, et al. "Vitamin D Supplements for Prevention of Covid-19 or other Acute Respiratory Infections: a Phase 3 Randomized Controlled Trial (CORONAVIT)." medRxiv (2022).
In the context of COVID-19, there is an inverse relationship between fibrinogen (helps blood to clot) and vitamin D levels. This means when vitamin D levels are low, fibrinogen levels are high which increases the risk of clots.
Wu, Wen-Xiu, and Dong-Rui He. "Low vitamin D levels are associated with the development of deep venous thromboembolic events in patients with ischemic stroke." Clinical and applied thrombosis/hemostasis 24.9_suppl (2018): 69S-75S.
In severe COVID-19, one of the main problems in the lungs are related to micro thrombi (small clots in the small blood vessels) which reduce the exchange of oxygen. Vitamin D can help to reduce this risk and potentially save lives.
My comments on LinkedIn
Strange studies which would detract from the importance of these essential nutrients. The relevance is for mortality in severe COVID19 not if there is evidence of a positive test. Severe disease is associated with microthrombi and both nutrients have an impact on coagulation. Small differences can be life or death.
Absolutely critical to ensure there is adequate levels of both essential nutrients.
Once the data was reviewed, here were my thoughts.
Took a closer look at the UK paper. They should have just stated that 86.3% were deficient and the highest level was 150nmol/L (Toxic above 400). The optimum level is likely to be about 200 - 250 therefore every person would have benefited from a short course of high dose supplementation. In order to get adequate dosing, it needs 350,000 iu so the doses used were clearly inadequate. In any case the relevance of vitamin D is about reducing the risk of lung microthrombi in severe disease.
Remember to supplement if required this winter.
Vitamin D and COVID-19 - Why so much confusion?