Deficiency in vitamin D leads to decreased muscular strength, energy, as well as muscle and bone pain. We’ve long recommended vitamin D supplementation, even as one study found that fair-skinned individuals can produce up to 20,000 IU in less than 30 minutes of sunbathing. By comparison, there are only 115 IU of vitamin D in one cup of fortified skim milk, and a typical vitamin D supplement is 1,000 IU. However, we still recommend taking a supplement because there is a major catch to trying to get your vitamin D only by heading outdoors: This phenomenon is limited almost entirely to the summer months. Anyone living north of the Texas Panhandle can’t produce any vitamin D during the winter months because of the angle of the sun to the earth’s surface. Our recommendation: Try to get 5,000 IU every day through a diet rich in salmon, tuna, eggs, yogurt, milk—and supps.
