In addition to dietary sources, exposure to ultraviolet B sunlight provides children and adults with additional vitamin D. It is also based on the precedent of preventing and treating rickets with 400 IU of vitamin D.
This recommendation is based on expert opinion and recent clinical trials measuring biomarkers of vitamin D status. Infants who are breastfed and children and adolescents who consume less than 1 L of vitamin D–fortified milk per day will likely need supplementation to reach 400 IU of vitamin D per day.
In 2008, the American Academy of Pediatrics increased its recommended daily intake of vitamin D in infants, children, and adolescents to 400 IU. Vitamin D deficiency in children can have adverse health consequences, such as growth failure and rickets.
