Vitamin D3 is the only vitamin our bodies can make with sun exposure, using the energy of UVB rays to convert 7-dehydrocholesterol into vitamin D3. (To note, one widely held opinion is that D3 is technically not a vitamin but a hormone). Without sufficient sun exposure, individuals may therefore become deficient in this valuable nutrient; it is estimated that one billon people worldwide have a deficiency or insufficiency, and up to half of U.S. adults and 30 percent of children and teenagers have a vitamin D deficiency. Currently, there are many reasons for decreased sun exposure, from living in sun-starved latitudes to wearing various forms of sun protection that protect against skin cancer. Additionally, most Americans do not eat enough dietary sources of vitamin D (e.g. cod liver, sardines, fish) to get a healthy dose of it, and fortified foods like milk and cereal simply do not provide enough of it. Furthermore, as we age, we are less equipped to produce sufficient quantities of this vital nutrient. Therefore, Vitamin D supplementation seems to be the best option for many individuals to receive the amount their bodies need.

Vitamin D3 sufficiency is essential for maximizing bone health, as it enhances intestinal absorption of calcium and phosphorus. Conversely, a deficiency can cause bone weakness (in the form of osteopenia, osteoporosis or osteomalacia), as well as muscle weakness, both of which increase the risk of bone falls and fractures. Fortunately, vitamin D3 supplementation can prevent and help correct these conditions.

Vitamin D deficiency is associated with obesity, hypertension, glucose intolerance, and metabolic syndrome (insulin resistance). It has also been associated with other chronic illnesses including fibromyalgia, fatigue, colon and prostate conditions, autoimmune disorders, chronic inflammation, and polycystic ovarian disease. Research into its connection with other conditions is ongoing. In essence, vitamin D3 provides valuable and complete health support.