The Essential Role of Vitamin D for Immune Response

A friend sent me a video this week showing Dr JoAnn Manson discussing the efficacy of Vitamin D against COVID-19. The video was produced in May 2020 and you can watch it in full here. It is about 5 minutes long but I can’t embed it here. A recent study (published May 2021) supports this showing a 78% lower risk of death with Vitamin D.

The video discusses the role of Vitamin D in the immune response against viruses based on clinical trials (and not just COVID-19) as well as how it benefits bone health and more. As health should be our number one priority since it is the foundation on which the rest of our life is built, I thought this was beneficial information to share.

Below is a transcript of the video if you prefer to read it. The transcript was made using Otter – the audio transcription app – which can be used for Zoom calls, meetings, lecture note-taking, video and more.

Video Transcript

Hello. This is Dr JoAnn Manson, Professor of Medicine at Harvard Medical School and Brigham and Women’s Hospital. I’d like to talk with you about vitamin D and COVID-19. Is there potentially a protective role?

We’ve known for a long time that it’s important to avoid vitamin D deficiency for bone health, cardiometabolic health and other purposes, but it may be even more important now than ever. There’s emerging and growing evidence that vitamin D status may be relevant to the risk of developing COVID-19 infection and to the severity of the disease.

We’ve known for a while that vitamin D is important to innate immunity and boosts immune function for getting viral diseases. We also know that vitamin D has an immune-modulating effect and can lower inflammation and this may be relevant to the respiratory response during COVID and the cytokine storm that’s been demonstrated.

Now, there are laboratory studies, cell culture studies of respiratory cells that document some of these effects of vitamin D. There’s also evidence that patients with respiratory infections do tend to have lower blood levels of 25 hydroxy-D; there’s now some evidence for COVID-19 patients as well. In an observational study from three South Asian hospitals, the prevalence of vitamin D deficiency was much higher among those with severe COVID illness compared to those with mild illness. In fact, there was about an eightfold higher risk of having severe illness among those who enter with vitamin D deficiency compared to those who had sufficient levels.

There’s also evidence from a meta-analysis of randomised clinical trials of vitamin D supplementation looking at acute respiratory tract infections, upper and lower. This was published in the British Medical Journal about two years ago and it did show that vitamin D supplementation was associated with a significant reduction in these respiratory tract infections. Overall only a 12% reduction, but among the participants who had profound vitamin D deficiency at baseline, such as a blood level of 25 hydroxy-D less than 10 nanograms per mil, there was a 70% lower risk of respiratory infections with vitamin D supplementation. So this evidence is becoming quite compelling.

Now I think it is important that we encourage our patients to be outdoors, being physically active, [and] of course supporting and maintaining social distancing. This will lead to increased synthesis of vitamin D in the skin just from incidental sun exposure. Also, in terms of diet, it is important for everyone to be reading food labels which often will list the vitamin D content. And food sources that are higher in vitamin D include fortified dairy products, fortified cereals, fatty fish, sundried mushrooms. And for patients who are unable to be outdoors and also have a low dietary intake of vitamin D, [it is] quite reasonable to consider a vitamin D supplement. For example, the recommended dietary allowance of vitamin D intake is 600 to 800 IUs a day but, during this period, certainly a multivitamin or supplement containing 1000 to 2000 IUs a day would be quite reasonable.

We are in the process of planning a randomised clinical trial of vitamin D supplementation – moderate to high doses – to see if it does have a role in reducing the risk of developing COVID-19 infections, and also reducing the severity of disease and improving clinical outcomes. But in the meantime, it’s important to encourage measures that will on a population-wide basis reduce the risk of vitamin D deficiency.

Thank you so much for your attention. This is JoAnn Manson, and stay safe.

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