Vitamin D, well known for its importance in calcium absorption and bone health, appears to be an essential player in many other facets of body chemistry from immunity to inflammation. Vitamin D deficiency has been implicated in a variety of chronic illnesses from diabetes to cancer. It is found in some types of fish, as well as the much maligned cod liver oil, and to a lesser degree in eggs and a few other foods. It is also produced in our skin when exposure to the sun's ultraviolet rays begins a series of biochemical reactions that lead to the creation of the active form of Vitamin D.

For children under a year of age, whose primary nutrition sources are breast milk, baby formula, and a limited variety of solids, and whose unprotected exposure to sunlight is best kept to a minimum, obtaining adequate Vitamin D may not be guaranteed.

The study results revealed a striking deficiency in Vitamin D intake. Among the entire study group, only 44-58% of all the infants met the 2003 standard of 200 I U. daily, and an even smaller 11-25% met the 2008 standards of 400 I.U.

This challenge was compounded by recent changes in the vitamin D minimum daily requirement recommendations. Back in 1997, the Institute of Medicine labeled 200 IU per day to be adequate for infants. (1). In 2003, the American Academy of Pediatrics endorsed this with their recommendation that all children start consuming 200 I.U. daily, starting around two months of life. But in 2008, the AAP revised that recommendation, increasing the daily dose to 400 IU and recommending that supplementation start within the first few days of life. So how easily has the typical baby diet met this standard?

A study published in the April 2010 issue of the journal, Pediatrics, looked at the nutritional histories of about 1600 infants between 2005-2007 to determine whether their food sources had provided adequate vitamin D to meet the established requirements for their age. (2) They knew that of the major nutritional sources available to infants, breast milk contains inadequate amounts of Vitamin D to meet the daily 400 I. U. requirement, and formula is fortified with Vitamin D, but an infant must consume one liter (about 33 ounces) per day to obtain the full 400 I. U. Infant multivitamin and vitamin D-only supplements are dosed to achieve 400 I.U. daily.

The researchers recruited women who were in their third trimester of pregnancy to participate. If their babies were born full term, were normal weight and did not have medical conditions that affected nutrition, they were enrolled. They surveyed the mothers approximately monthly regarding their infants' dietary and vitamin supplementation histories, starting at one month of age and continuing through 10.5 months.

Each survey questioned whether the infants received vitamin drops or pills and whether they had receiving breast milk, formula, or both for the preceding month. They asked the average number of feedings, as well as the ounces of formula consumed per day. From this data, they were able to calculate whether the infants' diets had supplied them with 400 IU of V D daily during that month.

The study results revealed a striking deficiency in Vitamin D intake. Among the entire study group, only 44-58% of all the infants met the 2003 standard of 200 I U. daily, and an even smaller 11-25% met the 2008 standards of 400 I.U.

Within the population surveyed, only 4-7 % were receiving an oral vitamin D supplement, with the exclusively formula fed group being the least likely to take additional vitamins. All breast fed infants require supplemental Vitamin D to meet past or current Vitamin D standards, yet the study showed that only 8-13% were in fact adequately supplemented. The infants who were both breast and formula fed did not receive nearly enough fortified formula to obtain their 400 I.U. In this group, 28-35% met the 200 IU mark while only 9-14% met the 400 IU.

Even the babies who only drank fortified formula were found lacking. While 90% of them met the 2003 standard, only 20-37% met the 2008 standard and these infants did so by consuming large amounts of fortified formula. The researchers noted that as infants grow and begin to expand their diet to solid foods, their formula consumption decreases. Thus, after about six months when this shift begins to take place, formula consumption becomes increasingly inadequate to supply vitamin D needs. The overall conclusion: Too many babies are not consuming enough vitamin D and most will require a vitamin supplement to do so.

What's a parent to do? First talk to you doctor. It is rarely a good idea to initiate vitamin supplementation or make major modifications in your infant's diet without discussing it with your baby's doctor.

There are good reasons why there are limits on the amount of formula that babies are given during various stages of infancy and increasing the quantity to the one-liter mark is not good solution to the problem of inadequate vitamin D intake. Similarly, breast milk is an excellent food for babies with a multitude of health benefits and should not be abandoned in the quest for Vitamin D. Your doctor can review your baby's nutrition and may recommend appropriate vitamin supplements that will address the D issue while maintaining an age- appropriate infant diet. And while parents are attending to their infants' vitamin D needs, they may want to chat with their own doctors about their levels of this increasingly appreciated vitamin.