Marks Daily Apple
Serving up health and fitness insights (daily, of course) with a side of irreverence.
31 May

Vitamin D and RDA for Children

2231765546 6e380da44eIt’s probably of little surprise that we take issue with some of the Recommended Daily Allowance values and how they’re often determined. Case in point: New research published in the Journal of Clinical Endocrinology and Metabolism suggests that the current children’s RDA for Vitamin D (200 IUs) does not sufficiently support the “bone growth and musculoskeletal health of children and adolescents.”

The RDA value for children was set at 200 IUs because, unlike testing for adults’ dosage, there wasn’t adequate research into the benefits of higher amounts.

Vitamin D deficiency is a growing problem around the world, including in developed countries where children spend little time outside. Questions have existed for some time regarding the adequacy of the current RDA, particularly for older children and adolescents, who undergo a great deal of bone growth. As the researchers of this study note, Vitamin D levels during adolescence have bearing on a child’s future bone density and risk for other diseases.

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).

The study notes that previous research has indicated no difference between daily and weekly supplementation of Vitamin D. To ensure full compliance, the researchers required weekly, on-site administration of the supplement.

At the end of the study periods, only those children who had received the “high” dosage of vitamin D had the recommended optimum serum (blood) levels as they are defined for adults. (There is less agreement about an ideal serum level for children.) Other benefits were seen in those who received the higher dose. Researchers observed “substantial increments in lean mass, bone area and bone mass” particularly in girls. Their observations from the study caused them to suggest that serum OHD-25 (vitamin D) levels in the mid-thirties (ng/ml) may be a reasonable and beneficial target for this age group. The researchers noted that adolescents would be less likely candidates for toxicity because of their body’s use of the vitamin for constant growth.

And vitamin D is essential for every last one of us. As the researchers note, “Low vitamin D levels are associated with an increased risk of certain cancers (breast and prostate), autoimmune disorders and cardiovascular diseases.” Other risks? Depression. Osteoporosis. Cognitive impairment. Gait imbalance. Older men and women, in particular, are at risk for low levels or deficiency because of less time commonly spent outside and a decrease in the skin’s ability to “process” the nutrient from natural sun exposure.

Our recommendation for seedlings (and everyone else!)… As always, eat a healthy diet, supplement wisely, and get primal by spending adequate time outdoors.

We’d love to hear your thoughts and questions.

Leo Reynolds Flickr Photo (CC)

Further Reading:

Seedlings and the “Need” for Nature

Not Enough B-6?

Let the Sun Shine In

Raise Healthy Seedlings

Supplementation

Eating Fabulous: Vitamin D in Brain Function, Supplementation May Be Necessary

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You want comments? We got comments:

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  1. In one sense RDAs are a joke. They only provide suggestions for the most basic of needs – to prevent things like scurvy. This is fine of course. But the problem is that this speaks nothing of the levels that far surpass RDAs that can have serious therapeutic value.

    32Simon wrote on May 31st, 2008
  2. Certainly, supplement when necessary, but if instead we encouraged everyone – and especially children – to be spending more time outside and active, we would kill 2 (or more) birds with one stone. It would work to up the Vitamin D, get more physical activity, which would help with weight problems, overall health, depression, and the list could go on and on.

    I realize not everyone lives in as warm and sunny a climate as I now do, but even so, for much of the year many people could go outside and get their Vitamin D that way. I’m all for getting things the “natural” way – food, sunlight – before taking a supplement, although I do take a daily multi (and give one to my sons) as well as fish oil.

    Judy wrote on May 31st, 2008
  3. Fish oil supplements are crucial. It is true that you can get Vitamin D via natural sunlight, and that the “natural” way is generally the preferable way to get most vitamins, but the “natural” way isn’t always the most convenient. If you live in a region with little sunlight throughout the year or you are just your average Joe that works indoors all day without a chance to get some sun on a regular basis, supplementation is essential. Also, as I alluded to above, certain nutrients/vitamins/minerals are nearly impossible to naturally ingest amounts that achieve levels that provide therapeutic effects. A comprehensive multi, as you say, is a good way to cover all your bases.

    32Simon wrote on May 31st, 2008
  4. Most people will have some sort of vitamin deficiency whether the RDA is correct or not.

    Bon wrote on June 1st, 2008
  5. We have 4 kids. Our teenager takes 1000 IU’s of vitamin D each day and our younger kids take 500 IU’s each day. They take this in high vitamin, good quality cod liver oil, so they’re getting their vitamin D WITH vitamin A and the omega 3’s – all together, the way they come naturally.

    Kelly the Kitchen Kop wrote on June 1st, 2008
  6. I read a number of blogs about health and especially the low carb way and the vit D issue appears all the time. I decided to check my 25OH D level and if it’s too low I will take supplement. The problem in my country is that I can’t find pure vit D (it is always with calcium or vitamin A, both of which I’m afraid to overdose). I remember there were some drops for kids when my daughter was small but they were sold on doc’s prescription.
    Can anybody point me to an online drugstore selling D without A and Ca? Maybe when dollars are now pretty cheap I will import it from the States :))

    zbiggy wrote on June 2nd, 2008
  7. Natural vs. synthetic vitamin A: 2 very different things. You can read more about it here: http://www.westonaprice.org/basicnutrition/clarifications.html

    Kelly the Kitchen Kop wrote on June 2nd, 2008
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