Should you take vitamin D supplements for COVID-19?

why is it important

Vitamin D has a profound effect on the innate immune system, our first line of defense, by stimulating antimicrobial peptides in mucous membranes. It also affects adaptive immunity by modulating T cell function.

All about nutrition and immunity The book “Let’s stop sabotaging our immunity” by Thierry Souccar

Two large meta-analyses have shown that vitamin D supplementation reduces the risk of respiratory infections, especially in people with vitamin D deficiency. Helps protect against COVID-19.

Observational studies have shown that people with vitamin D deficiency have an increased risk of severe COVID-19. However, this association may be due to reverse causation, as older and obese people are more likely to have a severe form of the disease and are also more likely to have deficits.

Two new studies

Two new randomized trials have just been published that refine our knowledge on this topic.

The first study was carried out in the UK from 2021 May to October. It involved 3,100 participants who took 3,200 IU or 800 IU of vitamin D3 daily for six months if their blood levels were below 75 nmol/L. Another 3,100 participants did not receive any supplementation.

The result: Neither of the two doses of vitamin D had any effect on the incidence of COVID-19. Therefore, this well-performed test is negative. However, caution should be exercised when drawing conclusions. First, vaccination was administered during the study. At baseline, only 1.2% of participants were vaccinated, but by the end of the study, 89.1% had received at least one dose. It is possible that vaccination masked any effect of vitamin D. However, in the unvaccinated group, the disease occurred less frequently among participants who consumed 3,200 IU per day compared to the control group, but the difference was not statistically significant. Second, the study was not double-blind, and vaccination was administered during the study. Finally, nearly 50% of the control participants took vitamin D supplements during the study period, which may have attenuated the effects of vitamin D.

Another tries was carried out in Norway from 2020 in November until 2021 in June, using cod liver oil as a substitute for low-dose (400 IU/day) vitamin D supplementation. Researchers randomized 34,741 participants to receive either 5 ml of cod liver oil or 5 ml of placebo oil daily for six months. The authors found no positive effect of cod liver oil.

However, participants were relatively young and healthy, and 86.3% had vitamin D levels considered adequate (>50 nmol/L) at baseline. Importantly, cod liver oil is high in vitamin A, which can also interfere with the effects of vitamin D on the immune system.

You can read the full Vitamin D and COVID file here (subscribers)

What lessons can be learned from these results?

In conclusion, null results from these studies should be interpreted with caution and does not rule out the possibility that vitamin D may be beneficial for people who are at risk of deficiency, of which there are many in winter: those with pigmented skin, those who rarely spend time in the sun, pregnant women, the elderly. In the comment published in the BMJ, Professor Peter Bergman of Sweden’s Karolinska Institute believes that ” For those with vitamin D deficiency (<50 nmol/L), supplementation of 1000-2000 IU per day may be a safe, simple, and affordable way to restore vitamin D levels, improve bone health, and enjoy potential protection.. ยป

Leave a Comment