What Causes Vitamin D Deficiency?

Vitamin D deficiency can be caused by any of the following:

  • Not enough exposure to sunlight. In the wintertime, when the sun’s rays are less strong, very little vitamin D is produced in the skin. Vitamin D levels can be affected by anything that blocks exposure of the skin to sunlight. This includes sunblock, being indoors for long periods of time, skin pigmentation (skin color) or long clothing.
  • Poor absorption of vitamin D in the gut because of certain medical conditions, such as celiac disease
  • A newborn baby may have vitamin D deficiency if the mother had vitamin D deficiency during her pregnancy

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Rev. 8/2019. MassGeneral Hospital for Children and Massachusetts General Hospital do not endorse any of the brands listed on this handout. This handout is intended to provide health information so that you can be better informed. It is not a substitute for medical advice and should not be used to treatment of any medical conditions.