Feature Health & Medicine Vitamin Boost From muscle strength to immunity, scientists find new vitamin D benefits By Janet Raloff October 5, 2004 at 11:00 am - More than 2 years ago Share this:Share Share via email (Opens in new window) Email Share on Facebook (Opens in new window) Facebook Share on Reddit (Opens in new window) Reddit Share on X (Opens in new window) X Print (Opens in new window) Print First in a two-part series. Part II: “Vitamin D: What’s Enough?” is available at Vitamin D: What’s Enough?. COVERED. Outdoor activities—even reading—build vitamin D in people as long as enough of a person’s skin is exposed to the sun. PhotoDisk The story of vitamin D would appear simple.