Vitamin D is responsible for maintaining normal blood levels of Calcium & Phosphorus. It aids in Calcium absorption for strong teeth & bones. Without it, your bones can become soft, change shape & begin to demineralize.
Exposure to natural sunlight is a major source of Vitamin D. Ultraviolet rays from the sun trigger vitamin D synthesis in your skin. Spending 20-30 minutes in the sun produces approximately 10,000 IU of vitamin D in your body. Of course, depending on the latitude of where you live (the further from the equator you are, the lower your Vitamin D levels) and the season will determine your sunlight exposure & hence your circulating levels of Vitamin D.
It's estimated that approximately 25 million adult Americans are at risk for developing osteoporosis, in part due to low levels of Vitamin D. Current research has implicated vitamin D deficiency to a variety of different cancers, autoimmune diseases, diabetes, heart disease & many more.
So what should you do? Have your Vitamin D levels tested to get a baseline & then begin supplementing. Optimal Vitamin D levels are 50-65 ng/ml.
When sunny weather prevails, get outside & expose yourself to the sun; vreate vitamin D naturally. You'll be doing your body a world of good.