However, a mountain of new evidence suggests that the vitamin may have a more versatile role than previously thought, particularly when it comes to maintaining a healthy immune system and boosting mood.
Low levels have been associated with more severe asthma, colds, seasonal affective disorder, and even chronic pain or fibromyalgia.
So does that mean that taking more vitamin D (or spending a bit more time in the sun) can combat fibromyalgia? Not just yet.
Studies have found that pain patients, including those with fibromyalgia, are more likely to be vitamin D deficient than their pain-free peers. However, its not clear which came first; people in pain may get less sun (presumably because they may be more likely to stay inside, due to pain), which could lead to a vitamin D deficiency, rather than vice versaa vitamin D deficiency leading to pain.
And its also not clear if making sure you have adequate levels of the vitamin will help relieve pain or other fibromyalgia symptoms, such as lack of energy or difficulty sleeping.
Whats known about vitamin D
Our bodies make vitamin D naturally when exposed to sunlight. It only takes 10 to 15 minutes a day outside (without sunscreen) to make an adequate amount, but according to studies, about half of adults and 70% of children dont get enough. In a 2003 study, 93% of pain patients had low levels of vitamin D.The dietary reference intake was revised in 2010 to attempt to clear up conflicting messages about the importance of vitamin D. The current recommended dietary allowance for people up to age 70 is 600 international units (IU) per day of vitamin D. Adults older than 70 need 800 IU/day, with an upper limit of 4,000 IU/day deemed safe.
Getting vitamin D from natural sources can stop you from getting too much of the vitamin, since the body makes only what it needs.
Although its hard to overdose on vitamin D, it is possible if you take megadoses of the vitamin, which can cause hypercalcemia, an above-average concentration of calcium in the blood that can lead to kidney failure and nervous system problems, and hyperphosphatemia, an increase in levels of phosphates in the blood, which can affect bone density and increase the risk of osteoporosis.
Many who lack vitamin Despecially during the dark and dreary winter months when sunlight isnt abundantdo turn to supplements. In 2008, Americans spent $235 million on vitamin D supplements, up from $40 million in 2001.