top of page

Low Vitamin D

The recent news linking low vitamin D to COVID-19 has turned many heads including my own. It's left many of us wondering about our own levels and adequacy.

Some of the most salient points in the scientific literature on vitamin D and COVID include:

1. 80% of COVID cases are vitamin D deficient.[1]

2. Risk of testing positive for COVID is 77% higher in those with low vitamin D levels.[2]

3. Low vitamin D may be linked to high inflammation and increased severity of COVID.[3][4]

These links between vitamin D deficiency and COVID-19 may be due to vitamin D's ability to increase white blood cells and ability to fight infection[5] and regulate inflammation[6]. Though much of the research is inconclusive and only makes associations between low vitamin D levels and COVID-19 risk and severity, it would be prudent to have your levels assessed as the benefits of vitamin D adequacy far outweigh the risks.

In addition to COVID-19 concerns, low vitamin D has also been linked to:

Risk factors for low vitamin D levels include:

  • Limited sun exposure

  • Working night shift

  • Darker skin color

  • Increasing age

  • Living in northern latitudes

  • Obesity

  • Malabsorption disorders (ie. Celiac, inflammatory bowel disease, gastric bypass surgery)

  • Kidney and/or liver disease

  • Medications (laxatives, cholesterol lowering drugs, steroid medications, anti-seizure medications)

Symptoms of low vitamin D:

  • Fatigue

  • Bone or muscle pain

  • Muscle weakness

  • Low mood

Because symptoms are vague, the best way to know if you’re vitamin D deficient is to test. Vitamin D tests generally are not covered by OHIP and cost $35-40. You will need a lab requisition from a health care practitioner who can then help determine the proper vitamin D dosage you’ll need to get your levels to a healthy range.

Natural sources of vitamin D include:

  • Sun exposure: Living in colder climates, with shorter days provides less UVB rays which hampers vitamin D production. Also consider air pollution, time of day (ideal is 10am to 2pm) and whether you live in the city (not ideal).

  • Cod liver oil: which generally provides about 1000iu per serving (check the label).

  • Fish (3oz): preferably salmon (450IU), tuna (150IU), sardines (175IU)

  • Beef liver (3oz) or egg yolk (1 large) provides about 40IU

If your levels are low, sun exposure and diet are likely not enough and the best way to get your levels up efficiently is to supplement orally or with vitamin D injections. However, vitamin D can accumulate in the body and become toxic, so make sure to retest your levels after supplementing with vitamin D for a period. Signs of vitamin D toxicity can include: nausea and vomiting, frequent urination, bone pain and kidney problems. Do not take high doses of vitamin D for prolonged periods.

Have more questions about vitamin D, or curious about your levels, get in touch with me and lets address your concerns.

In Health,


REFERENCES: [1] The Endocrine Society. (2020, October 27). Over 80 percent of COVID-19 patients have vitamin D deficiency, study finds: Vitamin D deficiency was more prevalent in men. ScienceDaily. Retrieved November 10, 2020 from [2] 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. doi:10.1001/jamanetworkopen.2020.19722 [3] Bilezikian, J., Bikle, D., Hewison, M., Lazaretti-Castro, M., Formenti, A., Gupta, A., Madhavan, M., Nair, N., Babalyan, V., Hutchings, N., Napoli, N., Accili, D., Binkley, N., Landry, D., & Giustina, A. (2020). MECHANISMS IN ENDOCRINOLOGY: Vitamin D and COVID-19, European Journal of Endocrinology, 183(5), R133-R147. Retrieved Nov 11, 2020, from [4] Rhodes, JM, Subramanian, S, Laird, E, Griffin, G, Kenny, RA (Institute of Translational Medicine, University of Liverpool, Liverpool, UK; Trinity College Dublin, Dublin, Ireland; St George’s, University of London, London, UK; Mercers Institute for Ageing, St James Hospital, Dublin 8, Ireland). Perspective: Vitamin D deficiency and COVID-19 severity – plausibly linked by latitude, ethnicity, impacts on cytokines, ACE2 and thrombosis. J Intern Med, 2020 [5] Mao, X., Hu, B., Zhou, Z. et al. Vitamin D levels correlate with lymphocyte subsets in elderly patients with age-related diseases. Sci Rep 8, 7708 (2018). [6] Yin, K., & Agrawal, D. K. (2014). Vitamin D and inflammatory diseases. Journal of inflammation research, 7, 69–87. [7] Rafiq S, Jeppesen PB. Is Hypovitaminosis D Related to Incidence of Type 2 Diabetes and High Fasting Glucose Level in Healthy Subjects: A Systematic Review and Meta-Analysis of Observational Studies. Nutrients. 2018 Jan 10;10(1):59. doi: 10.3390/nu10010059. PMID: 29320437; PMCID: PMC5793287. [8] Li X, Liu Y, Zheng Y, Wang P, Zhang Y. The Effect of Vitamin D Supplementation on Glycemic Control in Type 2 Diabetes Patients: A Systematic Review and Meta-Analysis. Nutrients. 2018 Mar 19;10(3):375. doi: 10.3390/nu10030375. PMID: 29562681; PMCID: PMC5872793. [9] Mirhosseini N, Vatanparast H, Mazidi M, Kimball SM. The Effect of Improved Serum 25-Hydroxyvitamin D Status on Glycemic Control in Diabetic Patients: A Meta-Analysis. J Clin Endocrinol Metab. 2017 Sep 1;102(9):3097-3110. doi: 10.1210/jc.2017-01024. PMID: 28957454. [10] 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. [11] Altieri B, Muscogiuri G, Barrea L, Mathieu C, Vallone CV, Mascitelli L, Bizzaro G, Altieri VM, Tirabassi G, Balercia G, Savastano S, Bizzaro N, Ronchi CL, Colao A, Pontecorvi A, Della Casa S. Does vitamin D play a role in autoimmune endocrine disorders? A proof of concept. Rev Endocr Metab Disord. 2017 Sep;18(3):335-346. doi: 10.1007/s11154-016-9405-9. PMID: 28070798. [12] Antico A, Tampoia M, Tozzoli R, Bizzaro N. Can supplementation with vitamin D reduce the risk or modify the course of autoimmune diseases? A systematic review of the literature. Autoimmun Rev. 2012 Dec;12(2):127-36. doi: 10.1016/j.autrev.2012.07.007. Epub 2012 Jul 7. PMID: 22776787. [13] Sunyecz J. A. (2008). The use of calcium and vitamin D in the management of osteoporosis. Therapeutics and clinical risk management, 4(4), 827–836. [14] Majeed F. (2017). Low levels of Vitamin D an emerging risk for cardiovascular diseases: A review. International journal of health sciences, 11(5), 71–76. [15] Chen WR, Qian YA, Chen YD, Shi Y, Yin DW, Wang H, Zhu P, Liu HW, Sha Y. The effects of low vitamin D on coronary artery disease. Heart Lung Circ. 2014 Apr;23(4):314-9. doi: 10.1016/j.hlc.2013.08.012. Epub 2013 Sep 3. PMID: 24161735. [16] Mirhosseini N, Vatanparast H, Kimball SM. The Association between Serum 25(OH)D Status and Blood Pressure in Participants of a Community-Based Program Taking Vitamin D Supplements. Nutrients. 2017 Nov 14;9(11):1244. doi: 10.3390/nu9111244. PMID: 29135923; PMCID: PMC5707716. [17] Spedding S. (2014). Vitamin D and depression: a systematic review and meta-analysis comparing studies with and without biological flaws. Nutrients, 6(4), 1501–1518. [18] Sue Penckofer, Mary Byrn, William Adams, Mary Ann Emanuele, Patricia Mumby, Joanne Kouba, Diane E. Wallis, "Vitamin D Supplementation Improves Mood in Women with Type 2 Diabetes", Journal of Diabetes Research, vol. 2017, Article ID 8232863, 11 pages, 2017. [19] Sommer I, Griebler U, Kien C, Auer S, Klerings I, Hammer R, Holzer P, Gartlehner G. Vitamin D deficiency as a risk factor for dementia: a systematic review and meta-analysis. BMC Geriatr. 2017 Jan 13;17(1):16. doi: 10.1186/s12877-016-0405-0. PMID: 28086755; PMCID: PMC5237198. [20] Licher S, de Bruijn RFAG, Wolters FJ, Zillikens MC, Ikram MA, Ikram MK. Vitamin D and the Risk of Dementia: The Rotterdam Study. J Alzheimers Dis. 2017;60(3):989-997. doi: 10.3233/JAD-170407. PMID: 28984598.


Follow Us
  • Instagram
  • Facebook Basic Square
  • Google+ Basic Square
bottom of page