What is vitamin D deficiency?

Vitamin D deficiency is a condition where the blood serum levels of vitamin D’s storage form, 25(OH)D or calcidiol, are lower than that which the body needs to properly maintain health.

A deficiency in vitamin D should not be allowed to remain uncorrected for too long, even in those who are healthy. The longer the deficiency is allowed to persist, the greater the risk of serious health complications such as chronic illness, debilitation, or even early mortality. 12345

There are only two ways to correct a vitamin D deficiency: sunlight exposure or vitamin D3 supplementation.

What causes vitamin D deficiency?

 Vitamin D deficiency occurs from lack of proper sun exposure.

Humans are designed to fulfill vitamin D needs by producing it in response to exposure to ultraviolet-B (UVB) light from the Sun. Vitamin D deficiency occurs as a result of a lack of consistent exposure of bare skin to the Sun’s UVB light.

The modern lifestyle

Human behavior, specifically the sun avoidance of the modern lifestyle, is the predominant factor influencing the rise we see in vitamin D deficiency today.

In addition, due to the physiology of vitamin D, certain members of the population are at even greater risk.

Vitamin D deficiency risk factors

 Blacks are at greatest risk of vitamin D deficiency, due to higher skin melanin content.

  • Insufficient UVB exposure – working and playing indoors, covering up with clothes or sunscreen when outside, residing at a high latitude.
  • Aging – seniors are at greater risk due to lack of mobility and skin that is less responsive to UVB. 6
  • Darker skin – high incidence of vitamin D deficiency and its associated conditions in Blacks is widely documented. 7891011
  • Breastfeeding – breastfeeding will result in vitamin D deficiency in the baby if the mother fails to ensure her own levels are high enough to provide for her baby’s needs. When the mother is deficient, the breast-fed child will be deficient due to the low vitamin D content of the mother’s breast milk. 1213
  • Obesity – fat-soluble vitamin D gets trapped in adipose tissue, preventing its metabolization and utilization by the body. 141516

What are the symptoms of vitamin D deficiency?

Symptoms of vitamin D deficiency could be described as chronic pain, weak bones, frequent infections, depression, etc., but the same will not be true for everyone who is deficient. Because the possible effects of vitamin D deficiency are wide-ranging and can manifest in the body in any number of ways, there are no specific associated symptoms.

Further reading:

Page last edited: 08 August 2011


  1. Ginde, A. A. Scragg, R. Schwartz, R. S. Camargo, C. A., Jr. Prospective study of serum 25-hydroxyvitamin D level, cardiovascular disease mortality, and all-cause mortality in older U.S. adults. J Am Geriatr Soc. 2009 Sep; 57 (9): 1595-603.
  2. Semba, R. D. Houston, D. K. Bandinelli, S. Sun, K. Cherubini, A. Cappola, A. R. Guralnik, J. M. Ferrucci, L. Relationship of 25-hydroxyvitamin D with all-cause and cardiovascular disease mortality in older community-dwelling adults. Eur J Clin Nutr. 2010 Feb; 64 (2): 203-9.
  3. Pilz, S. Dobnig, H. Nijpels, G. Heine, R. J. Stehouwer, C. D. Snijder, M. B. van Dam, R. M. Dekker, J. M. Vitamin D and mortality in older men and women. Clin Endocrinol (Oxf). 2009 Nov; 71 (5): 666-72.
  4. Zittermann, A. Gummert, J. F. Borgermann, J. Vitamin D deficiency and mortality. Curr Opin Clin Nutr Metab Care. 2009 Nov; 12 (6): 634-9.
  5. Barnard, K. Colon-Emeric, C. Extraskeletal effects of vitamin D in older adults: cardiovascular disease, mortality, mood, and cognition. Am J Geriatr Pharmacother. 2010 Feb; 8 (1): 4-33.
  6. Lister, T. Should long-term care residents be supplemented with vitamin D?. Can J Diet Pract Res. 2008 Spring; 69 (1): 28-31.
  7. Tseng, M. Giri, V. Bruner, D. W. Giovannucci, E. Prevalence and correlates of vitamin D status in African American men. BMC Public Health. 2009; 9191.
  8. Harris, S. S. Vitamin D and African Americans. J Nutr. 2006 Apr; 136 (4): 1126-9.
  9. Fiscella, K. Winters, P. Tancredi, D. Hendren, S. Franks, P. Racial disparity in death from colorectal cancer: does vitamin D deficiency contribute?. Cancer. 2010 Oct 13;
  10. Fiscella, K. Franks, P. Vitamin D, race, and cardiovascular mortality: findings from a national US sample. Ann Fam Med. 2010 Jan-Feb; 8 (1): 11-8.
  11. Dong, Y. Pollock, N. Stallmann-Jorgensen, I. S. Gutin, B. Lan, L. Chen, T. C. Keeton, D. Petty, K. Holick, M. F. Zhu, H. Low 25-hydroxyvitamin D levels in adolescents: race, season, adiposity, physical activity, and fitness. Pediatrics. 2010 Jun; 125 (6): 1104-11.
  12. Hollis, B. W. Wagner, C. L. Vitamin D requirements during lactation: high-dose maternal supplementation as therapy to prevent hypovitaminosis D for both the mother and the nursing infant. Am J Clin Nutr. 2004 Dec; 80 (6 Suppl): 1752S-8S.
  13. Saadi, H. F. Dawodu, A. Afandi, B. Zayed, R. Benedict, S. Nagelkerke, N. Hollis, B. W. Effect of combined maternal and infant vitamin D supplementation on vitamin D status of exclusively breastfed infants. Matern Child Nutr. 2009 Jan; 5 (1): 25-32.
  14. Herranz Antolin, S. Garcia Martinez Mdel, C. Alvarez De Frutos, V. [Vitamin D deficiency in morbidly obese patients. A case-control study]. Endocrinol Nutr. 2010 Jun-Jul; 57 (6): 256-61.
  15. Alemzadeh, R. Kichler, J. Babar, G. Calhoun, M. Hypovitaminosis D in obese children and adolescents: relationship with adiposity, insulin sensitivity, ethnicity, and season. Metabolism. 2008 Feb; 57 (2): 183-91.
  16. Vilarrasa, N. Maravall, J. Estepa, A. Sanchez, R. Masdevall, C. Navarro, M. A. Alia, P. Soler, J. Gomez, J. M. Low 25-hydroxyvitamin D concentrations in obese women: their clinical significance and relationship with anthropometric and body composition variables. J Endocrinol Invest. 2007 Sep; 30 (8): 653-8.

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