Sanjay Gupta on the Vitamin D Debate

The sunshine vitamin may help protect against cancer and flu, but how much do we need daily?

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A lot changed in between the births of my second and third daughters. For one thing, this time around I really am getting no sleep; for another, the pediatrician recommended something for our 1-month-old that is different from what had been suggested for our other children. She said we needed to pick up a liquid multivitamin that contains 400 international units (IUs) of vitamin D. It was a little confusing, because with our first daughter, now almost 4, the doctor told us to simply get her out in the sun from time to time to let her body produce vitamin D,...