Asthma, “a chronic inflammatory disorder of the airways,” affects approximately 10 percent of children. About half the risk is genetically determined, but we may have some control over the rest, which is the focus of my video Vitamin D for Asthma.

One reason asthma rates may be rising is because of our rising rates of vitamin D deficiency. Kids just aren’t going out to play anymore, which, as you can see at 0:30 in my video, resulted in a doubling of vitamin D insufficiency levels in recent years, such that less than a quarter of U.S. teens hit the mark.

We can’t make vitamin D, known as the sunshine vitamin, from the light coming from our TV, phone, and computer screens. “The primary sources of this vitamin are natural production in the skin secondary to sun exposure, and secondarily from fortified foods and supplements.” So, do kids with lower vitamin D levels in their blood have worse asthma? Apparently so. One of more than a dozen observational studies suggests that vitamin D is protective against “asthma exacerbations.”

Should we start giving kids with asthma vitamin D supplements if they’re not going to play outside? Correlation doesn’t mean causation. Perhaps “subjects with more severe asthma are likely to spend more time indoors,” thereby leading to less vitamin D, instead of the other way around. To prove cause and effect, we need to put it to the test. How? Randomize kids with asthma into one of two groups, receiving either vitamin D or an identical-looking sugar pill, and see what happens. There had never been clinical trials like that…until now.

Asthmatic kids were given 500 to 1,000 international units (IU) of vitamin D3 a day, and their asthma exacerbations were cut by more than half. Researchers suggest this may be due to decreasing the incidence of respiratory infections by boosting immunity, while, at the same time, diminishing inflammation.

If it helps with inflammation, what about inflammatory bowel disease? My video Vitamin D for Inflammatory Bowel Disease discusses exactly that.

For other videos in my extended series on vitamin D, see:

For more on preventing and treating asthma, check out:

In health,

Michael Greger, M.D.

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