Vitamin D, also known as the sunshine vitamin, is getting a lot of attention in the health headlines lately. While it is most well known for its role in bone health and calcium absorption, it seems that new research is continually uncovering other links between this vitamin and a variety of health conditions. This can raise the question of whether it is necessary to supplement with Vitamin D, and if so, how much? Too much can be toxic, so is it really safe to give this to your child without knowing their levels?
The American Academy of Pediatrics recommends that all breastfed or partially breastfed infants take 400 IU daily of Vitamin D3 (also known as cholecalciferol) until they are weaned to one liter of Vitamin D fortified milk or formula daily. The primary reason for this recommendation is to prevent Rickets, a disease causing softening and weakening of the bones due to prolonged Vitamin D deficiency. Of course, any child who does not consume foods naturally containing or fortified with Vitamin D should continue to take a supplement of at least 400 IU daily. As a Naturopathic Doctor, I often see babies who are weaned to alternative milks that may not be fortified with Vitamin D. I routinely recommend supplementation of Vitamin D through 2 years of age (and beyond, depending on dietary intake). During cold and flu season, I may even advise higher doses of Vitamin D based on a child’s age and other risk factors, since Vitamin D plays a key role in cell-mediated immunity.
What about toxicity? While toxicity can occur if large supplemental doses of Vitamin D are taken on a regular basis, the doses recommended by the AAP are considered safe for all infants and children, even those who may be getting adequate amounts of Vitamin D through diet alone. Under ideal conditions, the body can make 10,000-20,000 IU of Vitamin D from exposure to UVB from the sun’s radiation. In addition to the fact that our bodies can manufacture a significant amount of the necessary vitamin, the fact that it is fat soluble means it can be stored for seasons when sunshine is scarce. However, due to the increased use of sunscreen and other UV protection to prevent sunburn and skin cancer as well as decreased time spent outdoors, many people do not get their Vitamin D needs met even during the sunniest months of the year. For these reasons, I sometimes find it necessary to recommend doses higher than the minimum 400 IU in children (or 2000 IU in adults). It is important to note that the form of Vitamin D can make a difference in dosing required to reach toxicity. For this reason, the preferred supplemental form is Vitamin D3, also called cholecalciferol. The alternative form, less commonly used in supplements, but still prevalent in fortified foods is Vitamin D2, or ergocalciferol. Vitamin D2 tends to quickly reach higher concentrations in the blood, which makes it the preferred form for treating severe deficiencies (and also the only form currently available in large doses by prescription); however, it may not be the best form to take on a daily basis, since D3 tends to keep blood levels in the normal range for longer periods of time, is the “natural” form manufactured in our skin cells when exposed to UVB, is more shelf-stable, and is the form used in most clinical studies.
If you have questions about how much Vitamin D your child should take or concerns that your own Vitamin D levels may be deficient, you should talk to a licensed healthcare provider. Vitamin D blood tests are not routinely done with other recommended screening tests, but they may be ordered by a physician upon your request. Keep in mind, that depending on your medical history, the test may not be covered by your insurance provider. There are many labs that offer a discount for pre-paid or out-of-pocket tests, so it is worth looking into prior to having the test done. While testing is usually not necessary in healthy adults and children (supplementation of 400-2000 IU daily depending on age is safe without further testing), it can provide useful information in patients with chronic health conditions, since treating a Vitamin D deficiency can affect so many systems in the body. The most useful test for measuring the body’s stores of Vitamin D is the 25-hydroxyvitamin D test. Vitamin D3 is converted to 25-hydroxyvitamin D in the gut and then activated to 1,25-dihydroxyvitamin D by the kidneys. Both forms of “active” vitamin D are used in the body–our understanding of their roles and functions is really only the tip of the iceberg in terms of what Vitamin D actually does, since there is so much we are still learning and have yet to learn about this essential nutrient. (more info below)
Below are some links to additional resources on Vitamin D:
About the Author: Dr. Bowker is a Naturopathic Physician and owner of Snohomish Valley Holistic Medicine. In addition to her clinical practice, Dr. Bowker has volunteered for the Washington Association of Naturopathic Physicians and is a member of the WANP, AANP, and PedANP. She has also been a guest speaker for community organizations and instructor of several community health classes. For more information, please visit her primary website: www.snovalleyholistic.com