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 Click to share on Facebook (Opens in new window) Facebook Click to share on Reddit (Opens in new window) Reddit Click to share on X (Opens in new window) X Click to 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.