Ninety percent of our supply of vitamin D comes from the sun. One would think that, because of that, vitamin D deficiency is nothing to worry about, but experts argue that it remains prevalent. Those with darkly pigmented skin, those who are obese, elderly people, infants who are excessively breastfed, those with little or no sun exposure, and those with fat malabsorption conditions (e.g. celiac disease) are at highest risk for vitamin D deficiency.
A deficiency in vitamin D can cause soft bones, known in toddlers as rickets and in adults as osteomalacia. Vitamin D is responsible for regulating the formation of new bone structures (matrices). Bones are regenerating and reforming all the time, and, as such, when enough vitamin D is not present, defective bone mineralization occurs.
Symptoms of osteomalacia include bone pain (specifically, spinal, extremity, and pelvic bone pain), muscle weakness, hypocalcemia, compressed vertebrae, pelvic flattening, and bending of bones. Additionally, osteomalacious bones have extreme propensity to fracture, shatter, and/or break.
To keep your vitamin D up, spend some time outside each day. Taking a thirty-minute walk each day will give you a good dose, as well as burn calories and increase energy level. During the summer months, in any extreme sun temperatures, make sure to use sunblock with an SPF of 45 or greater while getting sunlight. Outside of getting sun, however, a suite of dietary vitamin D sources is a necessity, especially for those who may not have time to walk or cannot for medical reasons. Oily fish, vitamin-D-fortified foods such as orange juice, and vitamin supplements are your best bet.
Kwiatkowski, Kelly. The highs & lows of summer sun: the role of vitamin D in overall health and disease prevention. “To Your Health”, July 2007.