I’ve been getting this question a lot so I thought I would do a short blog breaking down what the experts and research are telling us about the correlation between vitamin D and Covid.
THE CLAIMS
The two main claims we are seeing are that vitamin D supplementation will prevent Covid or potentially reduce/minimize the symptoms.
Most of this is coming from the media picking up on some of the rapid research being conducted around the world in a multi-pronged effort to fight this virus. Normally, we lean on years of research to develop recommendations, but time is not on our side in this situation.
SOME BACKGROUND ON VITAMIN D
What is it? Vitamin D is a fat-soluble vitamin meaning it’s absorbed along with fats in the diet and is stored in the body’s fatty tissue and liver.
Where does it come from? It can be found in food, supplements and… the sun! Hence, why it's called the 'sunshine vitamin'.
What does it do? Its main function is to help your body maintain strong bones but your muscles also need it to move. For example, nerves need vitamin D to carry messages between the brain and every body part, and the immune system needs it to fight off invading bacteria and viruses. Together with calcium, vitamin D also helps protect older adults from osteoporosis. Emerging research suggests that vitamin D may also help prevent illnesses like depression, diabetes, cancer, and heart disease. However, its relationship to these conditions is still poorly understood.
How much do I need? The Recommended Daily Allowance (RDA) for adults <70 is 600 IU, over 70 is 800 IU. Though experts don't agree on this number. Some recommend upwards of 1500 IU. That being said, this is one of those vitamins that can be toxic if you have too much (again because it is fat soluble, stored in the body and not easily flushed out through your pee).
Sounds like everyone needs to get their vitamin D checked? Generally, no. Most people should be fine. Testing is important only for certain populations including:
People who are institutionalized
Patients with a gastrointestinal disorder (like inflammatory bowel disease) or osteoporosis
Those who have had weight loss surgery
Children who are immobilized and not outside and active
People over 70
People living in northern climates
People whose dietary habits include little or no dairy
WHY THE CONNECTION BETWEEN VITAMIN D AND COVID?
Vitamin D treatment has historically been found to decrease the occurrence of other viral respiratory tract infections, especially in patients with vitamin D deficiency, hence why researchers started to look into how it could impact Covid.
There are at least 14 published research studies and more than 54 in progress according to clinicaltrials.gov as of the publication of this article (a non-exhaustive list can be found at the end of this post for you science geeks) and in short:
There is not a consensus between the findings.
Some studies show a significant effect while others do not. One thing researchers are finding goes back to an old saying in science – Correlation does not equal causation. In other words, the populations most at risk for vitamin D deficiency also happen to be the same populations at risk for Covid, though one may not be causing the other.
According to the National Institutes of Health and the World Health Organization there is NOT enough conclusive evidence that vitamin D supplements prevent, decrease or minimize the symptoms of Covid and they therefore do NOT recommended that the general population take a vitamin D supplement. That being said, this is quickly evolving.
I know better than to go against global nonprofit organizations, because they have teems of scientists, with much more intimate knowledge than I have of the topic. But what I am seeing, is that as 2020 DRAGS on, we are seeing more studies published that report improved outcomes in Covid patients that were either not vitamin D deficient or those that were supplemented with vitamin D during their hospital stay.
According to Dr. Erin Talman, a board certified emergency medicine physician at Martha Jefferson Hospital in Charlottesville, Va, "Some hospitals have started to proactively administer vitamin D to Covid positive or suspected positive cases. Reason being, though the research is not conclusive yet, the potential benefits far outweighs any harms (which are minimal)."
WHAT DOES THE DIETITIAN RECOMMEND?
If you are in on of the at risk groups for deficiency, you could consider taking a supplement, but not more than the RDA. That being said, talk to your doctor first. They may do testing and recommend a specific dosing which may be higher than the RDA but is safe if you are being monitored.
For the rest of the population - eat your fruits, veggies, lean proteins and whole grains. Click here to find specific examples of foods high in vitamin D. Get outside for a little while every day and talk to your doctor if you are concerned.
As more and better research gets published, I will continue to keep a pulse on it and keep you all informed. Stay safe out there and...
WEAR YOUR DARN MASK.
If my 2 year old can, you can too!
A non-exhaustive list of some of the Covid and vitamin D studies completed in 2020
Jain, A., Chaurasia, R., Sengar, N.S. et al. Analysis of vitamin D level among asymptomatic and critically ill COVID-19 patients and its correlation with inflammatory markers. Sci Rep 10, 20191 (2020). https://doi.org/10.1038/s41598-020-77093-z
Kaufman HW, Niles JK, Kroll MH, Bi C, Holick MF. SARS-CoV-2 positivity rates associated with circulating 25-hydroxyvitamin D levels. PLoS One. 2020 Sep 17;15(9):e0239252. https://pubmed.ncbi.nlm.nih.gov/32941512/
Pizzini A, Aichner M, Sahanic S, Böhm A, Egger A, Hoermann G, Kurz K, Widmann G, Bellmann-Weiler R, Weiss G, Tancevski I, Sonnweber T, Löffler-Ragg J. Impact of Vitamin D Deficiency on COVID-19-A Prospective Analysis from the CovILD Registry. Nutrients. 2020 Sep 11;12(9):2775. https://pubmed.ncbi.nlm.nih.gov/32932831/
Meltzer DO, Best TJ, Zhang H, Vokes T, Arora V, Solway J. Association of Vitamin D Status and Other Clinical Characteristics With COVID-19 Test Results. JAMA Netw Open. 2020;3(9):e2019722. https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2770157
Welsh P, Mair FS, Gray SR, O'Donnell CA, Gill JM, Sattar N, Pell JP. Vitamin D concentrations and COVID-19 infection in UK Biobank. Diabetes Metab Syndr. 2020 Jul-Aug;14(4):561-565. doi: 10.1016/j.dsx.2020.04.050. Epub 2020 May 7. https://pubmed.ncbi.nlm.nih.gov/32413819/
Raisi-Estabragh Z, McCracken C, Bethell MS, Cooper J, Cooper C, Caulfield MJ, Munroe PB, Harvey NC, Petersen SE. Greater risk of severe COVID-19 in Black, Asian and Minority Ethnic populations is not explained by cardiometabolic, socioeconomic or behavioural factors, or by 25(OH)-vitamin D status: study of 1326 cases from the UK Biobank. J Public Health (Oxf). 2020 Aug 18;42(3):451-460. https://pubmed.ncbi.nlm.nih.gov/32556213/
Annweiler G, Corvaisier M, Gautier J, Dubée V, Legrand E, Sacco G, Annweiler C. Vitamin D Supplementation Associated to Better Survival in Hospitalized Frail Elderly COVID-19 Patients: The GERIA-COVID Quasi-Experimental Study. Nutrients. 2020 Nov 2;12(11):3377. https://pubmed.ncbi.nlm.nih.gov/33147894/
Annweiler C, Hanotte B, Grandin de l'Eprevier C, Sabatier JM, Lafaie L, Célarier T. Vitamin D and survival in COVID-19 patients: A quasi-experimental study. J Steroid Biochem Mol Biol. 2020 Nov;204:105771. https://pubmed.ncbi.nlm.nih.gov/33065275/
José L Hernández, Daniel Nan, Marta Fernandez-Ayala, Mayte García-Unzueta, Miguel A Hernández-Hernández, Marcos López-Hoyos, Pedro Muñoz-Cacho, José M Olmos, Manuel Gutiérrez-Cuadra, Juan J Ruiz-Cubillán, Javier Crespo, Víctor M Martínez-Taboada, Vitamin D Status in Hospitalized Patients with SARS-CoV-2 Infection, The Journal of Clinical Endocrinology & Metabolism, , dgaa733, https://doi.org/10.1210/clinem/dgaa733
D'Avolio A, Avataneo V, Manca A, Cusato J, De Nicolò A, Lucchini R, Keller F, Cantù M. 25-Hydroxyvitamin D Concentrations Are Lower in Patients with Positive PCR for SARS-CoV-2. Nutrients. 2020 May 9;12(5):1359. https://pubmed.ncbi.nlm.nih.gov/32397511/
Carpagnano GE, Di Lecce V, Quaranta VN, Zito A, Buonamico E, Capozza E, Palumbo A, Di Gioia G, Valerio VN, Resta O. Vitamin D deficiency as a predictor of poor prognosis in patients with acute respiratory failure due to COVID-19. J Endocrinol Invest. 2020 Aug 9:1–7. https://pubmed.ncbi.nlm.nih.gov/32772324/
Baktash V, Hosack T, Patel N, et al. Vitamin D status and outcomes for hospitalised older patients with COVID-19
Postgraduate Medical Journal Published Online First: 27 August 2020. https://pmj.bmj.com/content/early/2020/10/06/postgradmedj-2020-138712
Ohaegbulam KC, Swalih M, Patel P, Smith MA, Perrin R. Vitamin D Supplementation in COVID-19 Patients: A Clinical Case Series. Am J Ther. 2020;27(5):e485-e490. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7473790/