EASY Does It: Vitamin D

Printable Version 

An EASY guide to deciding whether to try something for COVID

When you are choosing whether or not to do something for your health, take it EASY! All four factors - 1) Effects, 2) Access, 3) Safety, and 4) You – can help you make a decision.

Tom is 68 years old and has heard a lot about different vitamins that could keep him from getting a viral infection like COVID or help to keep it from getting bad. He read that vitamin D (VD) can help but to stop taking it if you have an infection.¹ To decide what to do, he used the EASY guide:

Effects: VD is sometimes called “the sunshine vitamin,” because it is made in the skin from sunlight. It is important for healthy bones and helps the immune system, your body’s ways of fighting off infections. Study results are mixed, but overall, taking VD (in addition to what is in your food) might lower the chances of getting an infection, especially in people with low VD levels.^2-5 Some experts warn that you should stop taking VD supplements when you have an infection because studies in cells show that VD might make inflammation if you have an infection.^1,6,7 Studies in humans are needed to see if this is true.

Access: VD is found naturally in only a few foods, such as fatty fish, fish liver oil, and egg yolks from hens that have been fed VD. Dairy foods such as milk have added VD, but other dairy, like cheese and yogurt, might not have added D. VD is also naturally made in the skin when it takes in ultraviolet rays from sunlight. You can probably get all the VD you need by spending a short time outside with your face and arms exposed two to three times a week, but this can depend on your age, skin color, use of sunscreen, and where you live.⁸ If you live north of 40 degrees north latitude (Boston is 42 degrees north), you cannot get VD from the sun between mid-October and early March because of the angle of the sun.⁸ The body can store VD for use in winter, but winter might be a good time to take VD. The recommended dietary allowance (RDA) for VD is 600 IU/day for women and 800 IU/day for men.⁹ VD supplements are not costly.

Safety: VD toxicity does not happen from too much sun exposure, but you can get too much from supplements. The upper limit that is unlikely to cause harm is 4,000 IU a day for all adults.⁹ Some experts suggest that you might need to take 1,000 to 2,000 IU per day to bring you up to an adequate level.¹⁰ While VD supplements might protect you from getting sick, we just don’t know if it will it cause harm if you keep taking it while you are sick. VD is just one of many things that affects your immune system. Things such as whether you have an existing health condition, your genetics, and lifestyle factors such as diet, smoking, and physical activity can all affect how you respond to an infection.

You: Tom is doing what he can to stay healthy and fight off infections, including washing his hands often and physical distancing. He has been taking 1,000 IU of VD daily for many years and hopes his VD levels are in a good range to protect him from infection. He now understands that more research is needed to know whether he should stop taking VD if he gets sick.

Tom decides that if he gets sick, he will take a break from his VD just to be safe. Because he’s been taking it for a long time, he probably has some good stores that will get him through the illness, and he can start taking it again when he is feeling better.

NOTE: Dietary supplements are intended to supplement the diet. They are not medicines and are not intended to treat, diagnose, mitigate, prevent, or cure disease. In some cases, dietary supplements may have unwanted effects, especially if taken before surgery or with other dietary supplements or medicines, or if you have certain health conditions. Also, supplements are not regulated with the same degree of oversight as medications. Products vary greatly in terms of accuracy of labels, presence of contaminants, and the validity of claims on the label. Work with your health care provider to determine how best to achieve optimal health.

What we know about integrative health care has come to us thanks to the efforts, experiences, and collective wisdom of people from many cultures and backgrounds. We wish to acknowledge all the healers, researchers, patients, and peoples who have informed the content of this tool.

Author(s)

This handout was adapted for the Osher Center for Integrative Health at the University of Wisconsin-Madison from the original by Sara Arscott, PhD, and Adam Rindfleisch, MD.

Date Created: April 2020

References

1. Alschuler L, Weil A, Horwitz R, et al. Integrative considerations during the COVID-19 pandemic. Explore (New York, NY). Nov-Dec 2020;16(6):354-356.
2. Ginde AA, Mansbach JM, Camargo CA, Jr. Association between serum 25-hydroxyvitamin D level and upper respiratory tract infection in the Third National Health and Nutrition Examination Survey. Archives of internal medicine. Feb 23 2009;169(4):384-90.
3. Rejnmark L, Bislev LS, Cashman KD, et al. Non-skeletal health effects of vitamin D supplementation: A systematic review on findings from meta-analyses summarizing trial data. PLoS One. 2017;12(7):e0180512.
4. Autier P, Mullie P, Macacu A, et al. Effect of vitamin D supplementation on non-skeletal disorders: a systematic review of meta-analyses and randomised trials. The lancet Diabetes & endocrinology. Dec 2017;5(12):986-1004. doi:10.1016/s2213-8587(17)30357-1
5. Martineau AR, Jolliffe DA, Hooper RL, et al. Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data. BMJ. Feb 15 2017;356:i6583.
6. Tulk SE, Liao KC, Muruve DA, Li Y, Beck PL, MacDonald JA. Vitamin D₃ metabolites enhance the NLRP3-dependent secretion of IL-1β from human THP-1 monocytic cells. J Cell Biochem. May 2015;116(5):711-20. doi:10.1002/jcb.24985
7. Verway M, Bouttier M, Wang TT, et al. Vitamin D induces interleukin-1β expression: paracrine macrophage epithelial signaling controls M. tuberculosis infection. PLoS Pathog. 2013;9(6):e1003407.
8. Gombart AF. Vitamin D. Micronutrient Information Center, Linus Pauling Institute, Oregon State University. Updated 2021. Accessed March 3, 2025. https://lpi.oregonstate.edu/mic/vitamins/vitamin-D
9. Institute of Medicine (US) Committee to Review Dietary Reference Intakes for Calcium and Vitamin D. Dietary Reference Intakes for Calcium and Vitamin D. 2011. The National Academies Collection: Reports funded by National Institutes of Health.
10. Holick MF, Binkley NC, Bischoff-Ferrari HA, et al. Evaluation, treatment, and prevention of vitamin D deficiency: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. Jul 2011;96(7):1911-30. doi:10.1210/jc.2011-0385