A Vitamin D deficiency can occur for many reasons. For example, people with darker skin do not absorb UVB rays from the sun as well as those with lighter skin. In addition, sunscreen with SPF 30 cause the body not to synthesize 95% or more of the vitamin. Plus, people who live further north, work at night, are in high pollution areas, or stay inside most the time need Vitamin D from food. Finally, infants who only breastfeed, have dark skin, and/or little sun exposure are at risk for Vitamin D deficiency.