Research
Vitamin D Insufficiency Across US Demographics
Low serum vitamin D remains common among US adults, with rates rising during winter months and among people with darker skin, limited sun exposure, or older age. Insufficiency is most prevalent in northern latitudes and among indoor workers, though dietary fortification of milk and cereals has blunted the most severe deficiencies seen historically. Routine screening is not recommended for everyone, but targeted testing helps clinicians identify those who benefit from supplementation.
by HealthVetted ResearchPublished: May 29, 2026Source: NHANES serum 25-hydroxyvitamin D data; NIH Office of Dietary Supplements
41%
Adults with insufficient vitamin D
Low serum vitamin D remains common among US adults, with rates rising during winter months and among people with darker skin, limited sun exposure, or older age. Insufficiency is most prevalent in northern latitudes and among indoor workers, though dietary fortification of milk and cereals has blunted the most severe deficiencies seen historically. Routine screening is not recommended for everyone, but targeted testing helps clinicians identify those who benefit from supplementation.