Vitamine D en kinderen*
Uit een paar studies blijkt weer eens duidelijk dat de aanbevolen dagelijkse hoeveelheden voor
vitamine D veel te laag zijn, ook voor kinderen. Uit een eerdere Europese studie was al gebleken dat 80% van gezonde kinderen en pubers een duidelijk vitamine D tekort hebben, nu blijkt dat ook 80% van de kinderen met een lage botdichtheid een duidelijk tekort hebben. Een andere studie laat zien dat iedere dag minstens 50 mcg vitamine D door kinderen vanaf 10 jaar ingenomen moet worden om goede bloedwaarden vitamine D (> 30 ng/ml)te bereiken. In de studie werd zowel op korte termijn (8 weken) als op lange termijn (1 jaar) getest en belangrijk resultaat was ook dat geen enkel negatief effect werd vastgesteld. Toch is zowel in Amerika als hier in Nederland de aanbevolen dagelijkse hoeveelheid slechts 5 mcg en dat is slechts 10% van wat dus goed is voor iemand.
First study to examine vitamin D insufficiency in pediatric patients with low bone density
Vitamin D insufficiency is common in adults and is emerging in the world of pediatrics. A mild degree of vitamin D deficiency, also known as vitamin D insufficiency, causes rickets in children and can be treated with increased amount of nutritional vitamin D intake as well as increased sun exposure.
A new study conducted by physicians and researchers at Nationwide Children's Hospital, is the first study to investigate vitamin D insufficiency in pediatric patients with low bone density.
According to the study, published in the June issue of Pediatrics, among the 85 patients studied, 80 percent had a vitamin D insufficiency. All the patients had a history of bone fragility or underlying chronic medical conditions that put them at a risk of osteoporosis, which is not just an adult disease, but is seen in children and can originate during childhood. Vitamin D insufficiency may contribute to low bone mass or even make the underlying metabolic bone disease worsen if not treated. Vitamin D is essential in bone growth and mineralization in children and adults.
The study's lead author, Sasigarn Bowden, MD, a pediatric endocrinologist and attending physician in the Metabolic Bone Clinic at Nationwide Children's explains, "We need to check vitamin D levels in all patients with history of multiple fractures or low bone density and treat the vitamin D problem if the levels are low. The supplementation of vitamin D should be a priority in the management of pediatric patients with osteoporosis or osteopenia in order to optimize their bone health and potentially prevent fractures."
Potential factors that may account for vitamin D insufficiency in various chronic medical conditions include low vitamin D intake and decreased sun exposure. Four studies in Europe found that 80 percent of healthy children and adolescents had insufficient vitamin D levels in the winter.
"Due to the number of recent studies of healthy children or adolescents with a high prevalence of vitamin D insufficiency, the public should be aware of the fact that it is common, especially living in high altitude," said Bowden, also an assistant professor of Pediatrics at The Ohio State University College of Medicine. "Sometimes our vitamin D levels get low at the end of winter due to less exposure to sunlight, but if we take a multivitamin D supplement, or consume an adequate amount of vitamin D from dietary sources such as vitamin D fortified milk or orange juice, we should be okay throughout the entire year."
http://www.nationwidechildrens.org/
Current Vitamin D Recommendations Merely A Fraction Of Safe And Perhaps Essential Levels For Children
The current recommended daily allowance (RDA) of vitamin D for children is 200 International Units (IUs), but new research reveals that children may need and can safely take ten-times that amount. According to a recently accepted report in The Endocrine Society's Journal of Clinical Endocrinology & Metabolism (JCEM), this order-of-magnitude increase could improve the bone health of children worldwide and may have other long-term health benefits.
"Our research reveals that vitamin D, at doses equivalent to 2,000 IUs a day, is not only safe for adolescents, but it is actually necessary for achieving desirable vitamin D levels," said Ghada El-Haff Fuleihan, M.D., of the American University of Beirut-Medical Center, Lebanon, and lead author of the study.
Vitamin D is an essential hormone for bone growth and development in children and promotes skeletal health in adults. Currently, the National Academy of Sciences' Institute of Medicine recommends an adequate daily intake of 200 IUs of vitamin D for children. This is also the recommendation from the American Academy of Pediatrics. These levels, however, may not be adequate for bone growth and musculoskeletal health in children and adolescents.
"Data on appropriate vitamin D levels in the pediatric age group are lacking," said Dr. Fuleihan. "This is a major obstacle to finding the right daily allowance to enhance musculoskeletal health."
To help clarify these important guidelines, Fuleihan and his colleagues conducted both short- and long-term trials to gauge the safety of relatively high doses of vitamin D3 in children ages 10-17 years.
Vitamin D3 is one of the most common forms of vitamin D, and is easily converted to 25-OHD (25-hydroxyvitamin), which is the active form of vitamin D found in the blood.
For this placebo-controlled study, researchers gave children various doses of vitamin D at various intervals and measured the impact this had on serum levels of 25-OHD.
For the short-term study, 25 students (15 boys and 10 girls) received one-weekly, 14,000 IU doses of vitamin D for eight weeks. Serum levels of 25-OHD were then measured for an additional eight weeks. This portion of the test was conducted during the summer and early fall, when the highest natural levels of vitamin D are reached.
For the long-term, one-year study, 340 students (172 boys and 168 girls) received either a low dose of vitamin D (1,400 IUs each week) or a high dose (14,000 IUs each week).
Only children given the equivalent of 2,000 IUs a day of vitamin D increased 25-OHD levels from the mid-teens to the mid-thirties (ng/ml) the level considered optimal for adults. None of the children in either trial showed any evidence for vitamin D intoxication.
Although many experts agree that a 25-OHD level of 30 ng/ml is desirable in adults, what constitutes an optimal D level for children and adolescents is more debatable. According to the researchers, due to rapid skeletal growth, children and adolescents are more likely to be vitamin D deficient, and are far less likely to reach vitamin D levels that doctors would consider toxic.
"Supplementation of children and adolescents with 2,000 IUs a day of vitamin D3 is well tolerated and safe," said Dr. Fuleihan. "This is particularly relevant in light of the increasingly recognized health benefits of vitamin D for adults and children."
Other researchers involved in the study include Joyce Maalouf, Mona Nabulsi, Reinhold Vieth, Samantha Kimball, Rola El-Rassi, and Ziyad
Mahfoud.
The study "Short term and long term safety of weekly high dose vitamin D3
supplementation in school children" will be published in the July issue of JCEM.
Endocrine Society
8401 Connecticut Ave., Ste 900
Chevy Chase, MD 20815
United States
http://www.endo-society.org (Juni
2008)
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