Vitamin D is a fat-soluble vitamin that is essential for absorbing enough calcium and phosphorus for the body. It is needed for bone growth, mineralization and remodeling. According to the Office of Dietary Supplements, a vitamin D deficiency causes the bones to become brittle, thin and misshapen. Vitamin D also plays an important role in maintaining healthy immune and neuromuscular function in the body, and a deficiency can cause symptoms of fatigue and depression.
According to Merck Manuals Online, vitamin D is initially stored in the liver and present in two forms: vitamin D2, or ergocalciferol, and D3, or cholecalciferol. These forms are not active in the body, but need to be converted by the liver and kidneys to calcitrol, the active form of vitamin D, which promotes the absorption of calcium and phosphorus through the intestine. Vitamin D is called the sunshine vitamin because although it is present in few foods, the body will manufacture it when exposed to sunlight. It is found naturally in fatty fishes and fish oil, egg yolks and fortified foods, such as cereals.
It almost impossible to obtain adequate amounts of vitamin D through foods, so most vitamin D deficiencies result from the body not being exposed to enough sunlight. According to Vitamin D Deficiency Symptoms, a vitamin D deficiency can be especially troublesome in women, and certain symptoms, such as depression, mood changes and worsening of premenstrual syndrome, might be seen only in women. Other symptoms are excessive fatigue, daytime sleepiness, muscle weakness and vision problems. Children can develop a softening of the bones called rickets; in adults, osteomalacia or osteoporosis can occur. A vitamin D deficiency might play a role in the development of colon, breast, ovarian and bladder cancer.
Initially, blood tests are performed to determine the levels of calcium and phosphorus in the body. According to LabTestsOnline, if the levels of calcium and phosphorus are low, the level of 25-hydroxyvitamin D might be checked to confirm a vitamin D deficiency. Low blood levels of 25-hydroxyvitamin D indicate inadequate exposure to sunlight and dietary vitamin D.
Treatment and Prevention
The treatment for a vitamin D deficiency includes getting more exposure to the sun and adding a supplement of vitamin D to the diet. According to the National Institute of Arthritis and Musculoskeletal and Skin Diseases, it takes just 15 minutes in the sun without sunscreen a few times per week to manufacture enough vitamin D. Consult a physician about how much vitamin D supplement to add to your diet.
According to the Office of Dietary Supplements, some people are more at risk for developing a vitamin D deficiency. Breastfed infants might not receive adequate amounts of vitamin D through breast milk. People over 50 have decreased abilities to manufacture vitamin D through the skin and kidneys, and elderly, home-bound people might not get enough sunlight. Those with darker skin have larger amounts of melanin, which can reduce the amount of vitamin D absorbed from sunlight. Those with fat malabsorption or who have undergone gastric bypass surgery also are at risk.