Vitamin D: 40 ng/mL
Elle Penner, MPH, RD
5 mins
What does a vitamin D level of 40 mean?
A vitamin D level of 40 ng/mL is considered optimal. This means you are likely getting enough vitamin D from your diet, supplements, and/or routine sun exposure to support healthy bones, immune function, and overall health.
Not only is a level of 40 ng/mL good for your overall health, it also puts you at lower risk for certain upper respiratory infections (including COVID-19 and the flu), as well as type 2 diabetes and some autoimmune diseases, like multiple sclerosis, type 1 diabetes, and lupus [4,5,6,7].
How to maintain optimal vitamin D levels
- Continue consuming plenty of vitamin D-rich foods by eating foods like salmon, herring, canned tuna, eggs (with the yolk), and fortified milk, yogurt, and breakfast cereals
- Get 10–30 minutes of unprotected midday sunlight most days
- Continue to take a vitamin D supplement if you were supplementing previously
- Check your vitamin D level at least every 6 months (summer and winter) to ensure your levels don’t fall below 40 ng/mL. If your level falls in the winter, you may need to start supplementing or increase your supplement dose to maintain optimal levels.
- If you start a new medication, inquire about interactions with vitamin D.
References
- National Institutes of Health. (2021, March 26). Office of Dietary Supplements - Vitamin D. National Institutes of Health – Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/
- Alshahrani, F., & Aljohani, N. (2013). Vitamin D: deficiency, sufficiency, and toxicity. Nutrients, 5(9), 3605–3616. https://doi.org/10.3390/nu5093605
- Holick M. F. (2009). Vitamin D status: measurement, interpretation, and clinical application. Annals of epidemiology, 19(2), 73–78. https://doi.org/10.1016/j.annepidem.2007.12.001
- Demir, M., Demir, F., & Aygun, H. (2021). Vitamin D deficiency is associated with COVID-19 positivity and severity of the disease. Journal of medical virology, 93(5), 2992–2999. https://doi.org/10.1002/jmv.26832
- Kayaniyil, S., Vieth, R., Retnakaran, R., Knight, J. A., Qi, Y., Gerstein, H. C., Perkins, B. A., Harris, S. B., Zinman, B., & Hanley, A. J. (2010). Association of vitamin D with insulin resistance and beta-cell dysfunction in subjects at risk for type 2 diabetes. Diabetes care, 33(6), 1379–1381. https://doi.org/10.2337/dc09-2321
- Examine.com. (2019, April). A D-fence against cancer? https://examine.com/members/deep-dives/article/a-d-fence-against-cancer/
- Yang, C. Y., Leung, P. S., Adamopoulos, I. E., & Gershwin, M. E. (2013). The implication of vitamin D and autoimmunity: a comprehensive review. Clinical reviews in allergy & immunology, 45(2), 217–226. https://doi.org/10.1007/s12016-013-8361-3
