The Highs and Lows of Summer Sun
The Role of Vitamin D in Overall Health
By Kelly Kwiatkowski
It is well-known that vitamin D is essential in maintaining healthy bones. However, research over the past 10 years has shown that vitamin D is essential for overall health and disease prevention. In fact, several studies have linked vitamin D deficiency to many chronic diseases.
Vitamin D is a fat-soluble prohormone that helps regulate calcium absorption and bone metabolism. Evidence from cell-culture and animal studies shows that vitamin D also plays a role in regulating cell metabolism, insulin production, the immune system and inflammation - factors that contribute to a host of chronic diseases, including cancer, diabetes, high blood pressure, cardiovascular disease and many autoimmune disorders, such as MS and inflammatory bowel disease.
Sources of Vitamin D
We get 90 percent to 100 percent of our vitamin D requirements from the sun. The rest comes from natural and fortified dietary sources like oily fish, vitamin D-fortified foods, such as milk and orange juice, and vitamin supplements.
Vitamin D Deficiency
Despite a generally available source (sunlight), researchers argue that vitamin D deficiency remains prevalent. Factors contributing to vitamin D deficiency include: 1) the modest amount of vitamin D in fortified foods; 2) the reduction in milk consumption; 3) socioeconomic differences in milk and fortified cereal consumption; and 4) the avoidance of sun exposure due to the great concern about skin cancer and skin damage.
Classic vitamin D deficiency results in rickets (in infants) and osteomalacia (in adults). These are painful bone diseases that can lead to growth deficiencies and fractures. Thus, dietary sources of vitamin D are especially important for individuals more at risk for vitamin D deficiency. Individuals with darkly pigmented skin, those who are obese, elderly people, infants who are exclusively breastfed, people who get little or no sun exposure, and individuals with fat malabsorption conditions (e.g., celiac disease) are at higher risk for vitamin D deficiency.