Vitamin D Information from WebMD Website

Vitamin D, infants and teenagers: Your basic rock and hard place

Lately there have been a bunch of good news / bad news studies about vitamin D.

The good news: its benefits and preventive properties. The bad news: low levels of vitamin D in teenage girls and breast fed infants.

What should a pediatrician or a parent make of this new information? That's a tough question because it's not yet clear what it all means nor what (if anything) we should do about it.

Even tougher (at least for me): one of the conclusions I've come to from the new information contradicts some of my previous advice! That doesn't bother me: the beauty of science is that you must always be open to being wrong; you always need to re-evaluate in the face of new evidence.

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Advice-giving and sausage
Some advice-givers feel their advice should be like sausage: better to just consume the final product, but never see how it is made.

But I want you guys to be informed consumers of medical and parenting advice. Whenever possible, I'd like you to understand the science (or lack) that goes into the latest recommendations. And I'd like you to keep an open, questioning mind about about what people like me advise you to do.

Anyway, I've done my homework about vitamin D. Here is what I've found and here is my opinion.

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First, a crash course on vitamin D

• Vitamin D is more like a hormone than a vitamin. It plays a vital role in regulating the calcium in our bodies and making our bones strong.
• Vitamin D is usually made by converting a natural form of cholesterol - via exposure to ultraviolet (UV) light while in the blood vessels of our skin - to a non-active vitamin D, which is then further transformed in the kidneys and in the liver into its active form.
• Sun exposure is the most important source of vitamin D.
• As teenagers, we add on about 1/3 of our adult bone mass. It is widely accepted that if weaker bones are made during adolescence, there is a greater risk for softer bones ("osteoporosis") in later life.
• Breast milk contains inadequate vitamin D.
• Before cow's milk was supplemented with vitamin D, a nasty bone disease called rickets was quite common in children.
• The Institute of Medicine estimates that 2000 International Units (IUs)/day (e.g., found in 16 ounces of milk or formula) is needed to maintain good levels (some believe it should be even higher in older children and adolescents).
• The darker the skin, the less efficient the sun's rays are in activating vitamin D.

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The benefits of vitamin D
There is good scientific data to suggest that adequate vitamin D levels in children and adolescents has major benefits, including:

• Stronger bones as adults (especially in post-menopausal women).
• Better lung function in teens.***
• A protective effect against contracting some cancers (e.g., colon, breast****, prostate, ovarian).
  

Low vitamin D levels
Two very recent studies suggest that low vitamin D levels may be a lot more common than we thought:

• In a study of 51 (14 white/37 non-white) teenagers in England, 73% had low vitamin D levels. Dark-skinned girls were especially likely to have much lower levels. The low levels were felt to be due to reduced sunshine exposure, not to reduced vitamin D intake*.
• 78% of breast fed infants in Iowa who did not receive supplemental vitamin D were deficient (especially in the winter). **

Now, it's not clear how low is "too low" and what the consequences of low levels might be (if any). I'm going to make the leap - given what has been learned of its potential benefits - that low levels are not a good thing (especially in adolescence) and that children should maintain good levels of vitamin D.

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The rock and the hard place
Not so long ago I railed against direct sun exposure and urged you to obsessively apply sunscreen to your kids. That's my story and I'm sticking to it (pretty much).

But now I'm thinking I may have gone a little overboard in saying the only good sun exposure is no sun exposure, since it looks like too little direct sun exposure may lead to low vitamin D levels. (Alas, sunscreen probably blocks vitamin D production in the body. For more details, see this story)

So, what to do? Sun or no sun? Vitamin supplements or no? The rock or the hard place?

Kim's comments on this topic:

A comment that someone made to this article is that they find it hard to believe that the purely complete nutrition that breast milk provides does not give and has not given in the past everything that the baby needs. They want more research. I agree along these lines.

Also, my Mother had a good comment that you have to be careful about too much iron. If we do give Gwen the multi-vitamin supplement we should opt for the one without iron. I know they make both versions.

Maegen Connollyand Jade Brandstetter, since you two have education and experience with nursing, what do you think?