With the end of U.S. daylight saving time already on most people’s dislike list, here’s yet another reason to bemoan the earlier sunset: With less sunlight exposure, it’s difficult to get the vitamin D your body needs. And for those who live at higher latitudes, it’s nearly impossible in the fall and winter to make enough vitamin D from sun exposure alone. Vitamin D, which is produced when your skin is exposed to sunshine, is one of many nutrients our bodies need to stay healthy. This so-called “sunshine vitamin” helps the body absorb calcium and blocks the release of parathyroid hormone, both of which are important for strong bones. Vitamin D is also needed for healthy muscle and nerve function, and for proper functioning of the immune system. According to the Institute of Medicine, a vitamin D supplement is a good idea, since naturally vitamin D-rich foods are limited. For most people aged 9-70, the recommended dietary allowance is between 600 and 4,000 IUs. Be careful when taking supplements, however, since overly high levels of vitamin D can be harmful. To get more D from foods, choose fortified breakfast cereals and dairy products, as well as fatty fish such as salmon, tuna, and mackerel. Be aware that certain medications can interfere with vitamin D production and absorption, including antacids, diuretics, steroids (such as prednisone) , calcium channel blockers, and some weight-loss products.