Vitamin D, a fat soluble vitamin, helps build bone strength by aiding in calcium and phosphorus absorption and also plays a part in reducing inflammation and supporting the immune system. Vitamin D occurs naturally in few foods; most people obtain adequate vitamin D from sunlight exposure, the National Institutes of Health report. Some foods are also fortified with vitamin D. Vitamin D deficiency, defined as blood levels below 10 to 11 nanograms per milliliter, or ng/mL, occurs as a result of some diseases and causes other diseases.
Rickets/Osteomalacia
Rickets, which causes bones to become soft and weak, affects children when vitamin D, calcium or phosphorus levels fall below normal, MedlinePlus reports. Rickets in adults is called osteomalacia. Children most likely to develop rickets include exclusively breastfed babies, dark skinned children and those who don't get adequate sunlight exposure. Symptom include bone pain, skeletal deformities such as bowlegs, dental malformations, short stature and an increased number of bone fractures, the same source notes. Treatment includes increasing sunlight exposure and dietary sources of vitamin D or vitamin D supplements. Skeletal deformities may require special bracing or positioning to repair malformed bones.
Cystic Fibrosis
Cystic Fibrosis, or CF, a genetic disease that affects absorption of nutrients as well as lung function, often causes low vitamin D levels, even in children who receive vitamin D supplementation, Johns Hopkins Children's Center reports. Nearly half of all CF patients were vitamin D deficient in 2006, studies found, despite supplementation. Higher doses of vitamin D along with increased sunlight exposure may help prevent vitamin D deficiency in CF patients.
Crohn's Disease
Crohn's disease, chronic inflammatory bowel disease characterized by abdominal pain, diarrhea and ulceration of the small intestine, may be related to vitamin D deficiency, endocrinologist John White of the McGill University Health Centre reported in the January 28, 2010 issue of the "Vancouver Sun." Vitamin D deficiency also occurs as a consequence of Crohn's disease, which causes malabsorption of nutrients such as Vitamin D, the National Institutes of Health states.
Colon Cancer
A number of studies indicate that vitamin D deficiency plays a part in the development of colon cancer, the National Institutes of Health explains. It's not clear whether vitamin D plays a protective role in preventing colon cancer or if low vitamin D levels cause colon cancer, however.
