Vitamin D: Children Might Need Much More Than Thought

Kids may need a greater amount of vitamin D than today’s recommendations call for, the authors of a new study report.

According to the new research, children with low vitamin D blood levels did not achieve optimal levels even after taking nearly twice the recommended amount of the nutrient daily for six months.

Lead investigator Kumaravel Rajakumar, pediatrician at Children’s Hospital of Pittsburgh of UPMC and associate professor of pediatrics at University of Pittsburgh School of Medicine, remarked that Vitamin D is important for calcium metabolism and bone health.

Milk is usually fortified with Vitamin D, it is present in a few foods, and with sufficient exposure to sunlight the body naturally produces it.

“Vitamin D deficiency is common in the northeastern US, especially in black children whose darker skin complexions have higher amounts of melanin, preventing absorption of the ultraviolet light that’s needed to trigger vitamin D synthesis,” he explains.

In a randomized controlled trial, the researchers randomly assigned 84 black and 73 white 8- to 14-year-old children from Pittsburgh and Kittanning, Pennsylvania, to take either a daily pill of 1,000 international units (IU) of vitamin D3 or a placebo for a six month period. They also did periodic blood tests to check 25-hydroxyvitamin D levels and other markers of bone health.

Average vitamin D level at the first assessment of all participants, and particularly black children, was less than 20 ng/mL (suboptimal), and supplementation raised their average level to above 20 ng/mL but not as high as 30 ng/mL.

Following six months of vitamin D supplementation, in children with initial vitamin D levels less than 20 ng/mL, 39 percent remained below 20 ng/mL, and only 14 percent rose above 30 ng/mL. Biomarkers of bone turnover stayed unchanged.

“Our findings suggest that currently recommended daily dietary allowances of vitamin D of 600 IU may be inadequate for preventing vitamin D deficiency in children,” Rajakumar says. “It may be important to revisit these recommendations, especially since the higher dose of vitamin D used in this study was safe and did not appear to lead to any side effects.”

Effect of vitamin D3 supplementation in black and in white children: a randomized, placebo-controlled trial
Kumaravel Rajakumar, Charity G Moore, Jonathan Yabes, Flora Olabopo, Mary Ann Haralam, Diane Comer, Jaimee Bogusz,
Anita Nucci, Susan Sereika, Jacqueline Dunbar-Jacob, Michael F Holick, and Susan L Greenspan
The Journal of Clinical Endocrinology & Metabolism DOI: http://dx.doi.org/10.1210/jc.2015-1643

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