Vitamin D deficiency has become alarmingly widespread in recent years and is associated with consequences ranging from increased risk for some cancers to reduced athletic performance.
The main source of vitamin D is exposure to sunlight. One of the reasons vitamin D deficiency has become more widespread lately is that people aren’t spending as much time outdoors as they used to, and when they are outdoors, they’re often wearing sunscreens that block vitamin D synthesis. Many experts now recommend that people get 15 to 20 minutes of direct skin exposure to sunlight a few times a week to prevent vitamin D deficiency.
It’s a good idea to get your vitamin D levels checked by a physician periodically. If they are low, you may need to take a vitamin D supplement (D3 is the preferred form), at least during the winter.