Chronic back pain—the kind where you keep going to doctors and they can't find any specific problem—can be defeating. Try as you may, it seems that nothing takes away that general ache that can make it hard to do even the simplest things, like get out of bed.

It may be time for chronic back pain sufferers to walk on the sunny side of the street.

That's not a trite, "oh, just pull yourself together and get over it" statement. Vitamin D—aka, the sunshine vitamin—has been shown to help patients with chronic musculoskeletal pain. We get vitamin D from the sun (and from other sources, as explained in Calcium and Vitamin D to Build Bone); when the sun's rays hit your skin, your body becomes a vitamin D factory. Amazing.

Vitamin D helps your body absorb calcium, so without enough vitamin D, you won't get enough calcium. Without enough calcium, your bones can weaken, potentially leading to bone and joint pain, or musculoskeletal pain. (Lack of calcium and vitamin D can also lead to osteoporosis, as explained in Causes of Osteoporosis.) A recent review of clinical research by Pain Treatment Topics found that people with chronic musculoskeletal back pain always had insufficient levels of vitamin D. Then, when they bumped up their intake of vitamin D, their pain lessened dramatically.

This doesn't mean that you can just go on a picnic on a sunny day and take a few vitamin D supplements—and presto, your back pain is gone. Talk to your health care provider about how much vitamin D you should get every day and how you can get enough of it.

You won't notice an immediate effect from vitamin D; give it time to build up in your body and treat the source of your pain (your weakened bones and joints). Taking vitamin D is a commitment, and you should also stay committed to your other treatment options, such as pain medications and physical therapy. A multi-disciplinary approach like that is generally more effective than trying just one treatment at a time.

And if possible, get outside more on sunny days. That sunshine vitamin—vitamin D—may be just what your back needs.