ATLANTA (FOX 5 Atlanta) - For those who lather on the sunscreen, there may be a hidden downside to protecting your skin.
You could be making it harder for your body to produce Vitamin D, which we need to build strong bones.
Studies have shown more than 40 percent of Americans may be deficient in Vitamin D.
Dr. Taz Bhatia of CentreSpring MD says the warning signs are not always obvious.
"Some that we've noticed are depression, hair loss, getting sick all the time," Dr. Bhatia says. "Those are probably the 3 most common signs of vitamin D deficiency. But, they're not blaring or blatant, like an iron deficiency or a B 12 deficiency, or a magnesium deficiency. They're not as obvious as those."
Food is a good source of Vitamin D -- especially fatty fish, like salmon and trout, egg yolks, and fortified dairy and grain products. But, you may not be getting enough, if you're vegan, don't get sun much exposure, or have digestive issues that keep you from absorbing nutrients like you should.
People who are obese or have darker skin are also more like to be low in Vitamin D.
A chronic Vitamin D deficiency has been linked to weight gain, fatigue, osteoporosis, even heart disease.
Dr. Bhatia says there is new research that shows Vitamin D may play a role in insulin production, helping to lower our risk of developing type 2 diabetes.
"I'm not surprised, because diabetes is an autoimmune disease, and Vitamin D plays a critical role in helping the immune system, and helping to body respond to inflammation," Bhatia says.
If you're feeling run down, Dr. Bhatia says, ask your doctor to do a blood test to check your Vitamin D levels. If you're low, try a supplement. Your doctor may recommend a prescription form of Vitamin D. Bhatia recommends eating Vitamin D-rich foods. And you may want to get out in the sun more often. But hold off on the sunscreen, at least for a few minutes.
"We do find that vitamin D levels are a little bit better in the summer than they are in the winter," she says. "But, for the people that are chronically-low, it's not the answer."