Vitamin D, also known as the “sunshine vitamin”, is a fat-soluble vitamin that can be produced in the skin with sufficient sunlight exposure.
It is best known for its crucial role in bone health. Without it, the body would not be able to absorb calcium from the intestines. Without adequate calcium absorption, the body “borrows” calcium from the bones, increasing the risk of osteoporosis and fracture. Furthermore, Vitamin D also helps maintain normal blood levels of phosphorus, another bone building mineral.
Vitamin D is so vital to bone health that, prior to the advent of fortification of foods, diseases caused by severe deficiency, such as rickets in children and osteomalacia in adults, where considered common.
New research on Vitamin D is constantly emerging on the numerous other benefits this vitamin has on health. Low levels have been linked to insulin resistance and diabetes, inflammation, impaired immunity, as well as being implicated in certain autoimmune conditions and cancer. As more and more research is conducted, the potential benefits of this “sunshine vitamin” are rapidly expanding.
Under ideal conditions, ten minutes of summer sun exposure to just the hands and face results in the production of approximately 400IU of Vitamin D. And yet, it is estimated that the majority of the North American population is Vitamin D deficient.
Many factors can impair the process of Vitamin D synthesis. The factors affecting synthesis in the skin are many and include season, time of day, latitude, cloud cover and pollution. Except during the summer months, the skin is able to make little if any Vitamin D from the sun if you live at latitudes above 37 degrees north (that means all of Canada and most of the United States).
Furthermore, Vitamin D production is also influenced by skin colour (darker skin tones will have less production due to increased skin pigments which block UV light absorption), and age (people ages 65 and up have a decreased production of Vitamin D), a well as sunscreen use. Even in the summer months, the use of sunscreen (although excellent for protecting the skin against the harmful effects of the sun) further blocks your skin’s ability to produce.
Since your body is not always producing adequate amounts of D, dietary sources and supplementation should be considered. Food sources include canned sardines, salmon, tuna, sunflower seeds, liver, eggs, mushrooms, and fortified milk.