The American Academy of Pediatrics says children - from newborns up to teenagers - should be given double the current recommended amount of vitamin D because research has shown it may help prevent serious diseases.
America's leading pediatricians say the new recommendation of 400 units daily, means millions of children will need to take double the dose of daily vitamin D supplements.
This new advice includes babies who are still being breast-fed and some infants being fed formulas, as well as many teenagers who drink little or no milk.
As most baby formula contains vitamin D, infants on formula do not generally need supplements but the academy which recommends breast-feeding for at least the first year of life, says breast milk is sometimes deficient.
Dr. Frank Greer, the report's co-author says most commercially available milk is fortified with vitamin D, but most children and teens don't drink as much as the four cups daily needed to meet the new recommendation of 400 units daily.
The new advice comes as a result of a plethora of recent research about the potential benefits from vitamin D aside from keeping bones strong - there are suggestions that vitamin D might reduce risks for cancer, diabetes, autoimmune diseases and heart disease.
Advice in 2003 from the Academy of Pediatrics recommended 200 units daily which is the same as government recommendations for children and adults up to age 50; 400 units is recommended for adults aged 51 to 70 and 600 units for those aged 71 and up.
Vitamin D is available in drops for young children and in capsule and tablet form and the Institute of Medicine, a government advisory group that sets dietary standards, is currently discussing with federal agencies whether those recommendations should be changed on the basis of new research.
The best source of vitamin D is sunlight because the body makes vitamin D when sunshine hits the skin and it is found in oily fish including tuna, mackerel and sardines - while milk and some other fortified foods like cereal contain vitamin D, it is difficult to get enough through diet alone.
It is thought that 10 to 15 minutes in the sun without sunscreen a few times a week is sufficient, but many people such as those with dark skin and those in northern, less sunny climates need more.