Many doctors say fortified foods aren't enough. So an influential pediatrics group says it's time to bump up the recommended dosage.
In the Gruber home, like so many others across the United States, multivitamins are part of the breakfast routine.
Max and Jack Gruber have been taking their vitamins for years.
"If the pediatricians say they should be getting more vitamin D then that's what we will do," said Andrew Gruber, father of Max and Jack.
The American Academy of Pediatrics is now recommending Vitamin D be doubled for all children from 200 international units to 400 international units daily.
Why such a dramatic increase?
Vitamin D is known to promote strong bones but doctors started getting concerned when rickets, a condition from the past started to re-emerge.
And then in the past couple of years more studies were raising concerns that the lack of this essential vitamin could be linked to cancer, diabetes , heart disease and even depression in children.
"I think it really has been under appreciated how much it generally plays in our health care overall," said Dr. Craig Langman, kidney disease specialist, Children's Memorial Hospital.
Dr. Langman at Children's Memorial Research Center has been studying vitamin d levels in children for decades. And what he finds may be surprising.
Dr. Langman says his soon to be published research from the 1990s and 2006 shows between 50 to 70 percent of the thousands of children screened were vitamin d deficient.
"So I think it's going to be very important to change the paradigm of care and start seeing much more supplementation," said Langman.
But not everyone is on board.
The current U.S. nutritional standards for vitamin d have not changed. There's still concerns about the benefits and safety.
An independent board that advises federal agencies is trying to come up with its own evidence based guidelines.
Dr. Langman doesn't need convincing.
"There was great concern because it was a fat stored vitamin that there would be toxicity to patients but we now understand that's not the case.. the body regulates this very exquisitely," said Langman.
Many pediatricians agree with recommendations to double the amount. And they are passing the advice on to parents, especially to those who are breast feeding.
"Breast Milk is the best form of nutrition for infants by far but there is one thing we don't quite have the levels of Vitamin D that we need," said Dr. Jennifer Bryan, pediatrician.
Seven-month-old Julia Gorcik gets her vitamins daily. Her parents were told shortly after Julia was born that a nursing baby needs the extra Vitamin D.
"It does give me piece of mind that we are giving her something that's going to keep her healthy," said Margaret Gorcik, mother of Julia.
While there is no consensus on exactly how much Vitamin D children should be taking, most doctors agree it should be no fewer than 200 international units a day.
Doctors warn these new guidelines are not permission to go overboard on Vitamin D. Too much can be harmful, so consulting a practitioner is recommended.
Also, many of the children's supplements sold over the counter are already providing the 400 international units of Vitamin D.
American Academy of Pediatrics
Dr. Craig Langman
Children's Memorial Hospital
2300 Children's Plaza
Chicago, Il. 60614
Institute of Medicine of the National Academies
National Institutes of Health
Office of Dietary Supplements