Are your children getting enough Vitamin D?

This post was contributed by Caitlin Hosmer Kirby, MS, RD, a senior nutritionist at Harvard-affiliated Brigham and Women’s Hospital in Boston, MA. Thank you, Caitlin!

Are your children getting enough Vitamin D? The answer for most is NO. Up to 52% of teenagers have been found to be vitamin D deficient; 32% of medical students were deficient even though they take a multivitamin and drink one glass of milk daily. These deficiencies are based on measures that may themselves be inadequate.

Recently fifteen experts from universities, research institutes, and university hospitals around the world called for international agencies to “reassess as a matter of high priority” dietary recommendations for vitamin D because current advice is outdated and puts the public at risk of deficiency (The American Journal of Clinical Nutrition, Vol. 85, pp. 860-868, March 2007).

Why do we need Vitamin D?

Current research has implicated vitamin D deficiency as a major factor in the pathology of at least 17 varieties of cancer as well as heart disease, stroke, hypertension, autoimmune diseases, diabetes, depression, chronic pain, osteoarthritis, osteoporosis, muscle weakness, muscle wasting, birth defects, periodontal disease, and more. In the October 2008 newsletter of the Vitamin D Council, Dr. John Cannell also writes that “activated vitamin D almost assuredly varies among organs as well, explaining why one vitamin D deficient child gets asthma, another frequent infections, another heart disease, another rickets, another diabetes, and another cavities. When the vitamin D deficiency occurs in the womb, the results also vary in later life, from autism to type-1 diabetes to cancer.”
Factors that decrease or block the natural formation of vitamin D in the skin (the most effective form of the vitamin) include: using sunscreen, living in a location above 40 degrees North latitude (north of Atlanta), having dark skin, being overweight and being elderly.  (While being elderly is an increased risk of deficiency because our skin less effectively converts the sun to active vitamin D, this is a crucial vitamin along the entire life cycle including during pregnancy.)

How much Vitamin D is enough?
The American Academy of Pediatrics recently increased the recommendation for children from 200 IU to 400 IU.  While it is encouraging to see a response to the research, this is still woefully inadequate.   Most multivitamin formulations, including those for children, look to a national recommendation for levels of vitamin D and so provide an inadequate amount.  Some more informed and progressive companies have already improved their formulations to include larger quantities of vitamin D but this is happening slowly.

Individuals vary in their ability to use Vitamin D. However, as a general rule, breast-fed infants need 1,000 IU per day whereas bottle-fed infants need 600 IU per day. Children generally need about 1,000 IU for every 25 pounds of body weight. So a 75 pound nine-year-old needs about 3,000 IU per day. They don’t need to take it in the summer if they spend time outside without sunblock. Canada has recommended that everyone take at least 2,000 IU a day, safe for both children and adults as a maintenance dose.

What kind of Vitamin D should I use? Where can I get it?

Be sure to use Vitamin D3. D3 in 1,000 IU tablets by Nature Made are available in most pharmacies in the USA and Canada. Bio Tech Pharmacal offers great prices on 1,000 and 5,000 IU capsules. Life Extension Foundation also offers 1,000 and 5,000 IU capsules.  Ddrops from Carlson with 400, 1,000 and 2,000 IU per drop, are perfect for children.  LifeSpan Nutrition has a variety of vitamin D preparations.

Further reading:

Hunter D, et al. Genetic contribution to bone metabolism, calcium excretion, and vitamin D and parathyroid hormone regulation. J Bone Miner Res. 2001 Feb;16(2):371-8.

Wjst M, et al. A genome-wide linkage scan for 25-OH-D(3) and 1,25-(OH)2-D3 serum levels in asthma families. J Steroid Biochem Mol Biol. 2007 Mar;103(3-5):799-802.

Orton SM, et al. Evidence for genetic regulation of vitamin D status in twins with multiple sclerosis. Am J Clin Nutr. 2008 Aug;88(2):441-7.

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