AceShowbiz - Gwyneth Paltrow learned Hollywood's pale and interesting trend can have serious health consequences when she was diagnosed with a severe Vitamin D deficiency. Like many stars, the "Iron Man" actress insisted on staying out of the sun and covered up for summer trips - but then she learned her caution was costing her good health.

In her latest Goop.com online newsletter to fans and friends, the actress has opened up about her secret health battle and advised others how to make sure they get just the right amount of sun with a little help from top doctor Frank Lipman. Paltrow writes, "I suffered a pretty severe Tibial plateau fracture a few years ago (requiring surgery) which lead the orthopaedic surgeon to give me a bone scan, at which point it was discovered I had the beginning stages of osteopenia."

"This led my western/eastern doctors in New York to test my Vitamin D levels, which turned out to be the lowest they had ever seen (not a good thing). I went on a prescription strength level of Vitamin D and was told to... spend a bit of time in the sun!"

"I was curious if this was safe, having been told for years to stay away from its dangerous rays, not to mention a tad bit confused as we are all well schooled in the dangers of overexposure to the sun." Paltrow admits she took Dr. Lipman's advice and has now reversed her Vitamin D diagnosis, and she has called on the expert to offer readers tips on how to enjoy the summer sun's rays "sensibly".

He writes: "Numerous studies have shown that optimizing your Vitamin D levels may actually help prevent as many as 16 different types of cancer including pancreatic, lung, breast, ovarian, prostate, and colon cancers. And the best way to optimize Vitamin D levels is through safe, smart and limited sunscreen-free exposure to the sun."