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Hoe vitamine D tekort aanpakken?*
In het Amerikaanse vakblad American Family Physician werd bekeken hoe het beste een vitamine D tekort aangepakt kan worden. Vitamine D is volgens hen belangrijk voor een optimale opbouw van het skelet, het handhaven van een goede botgezondheid en goede zenuw-spierfuncties. Verder speelt vitamine D een belangrijke rol tegen het optreden van hart- en vaatziektes, depressies en darmkanker. Een vitamine D tekort geeft pas op langere termijn niet specifieke klachten en wordt daardoor vaak niet vastgesteld. Doch ouderen, donker gekleurde mensen, zij die weinig buiten komen, mensen met duidelijk overgewicht en zij die bepaalde medicijnen slikken zoals bijv. anti-eleptica, statines en corticosteroïden hebben bijna allemaal een tekort aan vitamine D (bloedwaarde < 30 ng/ml). Tekorten kunnen het beste aangevuld worden door 8 weken lang iedere week 1.250 mcg vitamine D in te nemen. Mochten de bloedwaarden dan nog lager zijn dan 30 ng/ml dan wederom 8 weken iedere week 1.250 mcg. Om de bloedwaarden op peil te houden lijkt daarna dagelijks minimaal 25 mcg nodig.
Management of Vitamin D Deficiency Reviewed 
Best practices for recognition, prevention, and management of vitamin D deficiency in the family practice setting are reviewed in the American Family Physician. Vitamin D is essential for optimal skeletal development, maintenance of bone health, and neuromuscular function. In addition, vitamin D may play important roles in guarding against cardiovascular disease, depression, and colon cancer.
"In the 19th century, vitamin D deficiency was identified as the cause of the rickets epidemic in children living in industrialized cities," write Paula Bordelon, DO; Maria V. Ghetu, MD; and Robert Langan, MD, from St. Luke's Family Medicine Residency Program in Bethlehem, Pennsylvania. "This discovery led to the fortification of various foods, and the resolution of a major health problem associated with vitamin D deficiency. However, recent studies have shown that vitamin D deficiency and insufficiency are associated with other pathologic conditions in persons of all ages."
The diagnosis of vitamin D deficiency is often missed and the condition untreated because the signs and symptoms develop slowly or are nonspecific. These may include symmetric low back pain in women; proximal muscle weakness; muscle aches; and throbbing bone pain in the low back, pelvis, or lower extremities, or when pressure is applied to the sternum or tibia. Vitamin D deficiency may also be recognized in patients who have increased risk for falls and impaired physical function.
Risk factors for vitamin D deficiency include age older than 65 years, exclusive breast-feeding without vitamin D supplementation; dark skin; insufficient exposure to sunlight; sedentary lifestyle; and obesity, defined as body mass index greater than 30 kg/m2. In addition, use of anticonvulsants, glucocorticoids, or other medications that affect vitamin D metabolism may give rise to deficiency.
Diagnosis of suspected vitamin D deficiency is confirmed with a 25-hydroxyvitamin D level of less than 20 ng/mL (50 nmol/L). Vitamin D insufficiency is defined as a serum 25-hydroxyvitamin D level of 20 to 30 ng/mL (50 - 75 nmol/L).
Recognition and management of vitamin D deficiency.
Bordelon P, Ghetu MV, Langan RC.
St Luke's Family Medicine Residency Program, Bethlehem, PA 18017 , USA.
Vitamin D deficiency affects persons of all ages. Common manifestations of vitamin D deficiency are symmetric low back pain, proximal muscle weakness, muscle aches, and throbbing bone pain elicited with pressure over the sternum or tibia. A 25-hydroxyvitamin D level should be obtained in patients with suspected vitamin D deficiency. Deficiency is defined as a serum 25-hydroxyvitamin D level of less than 20 ng per mL (50 nmol per L), and insufficiency is defined as a serum 25-hydroxyvitamin D level of 20 to 30 ng per mL (50 to 75 nmol per L). The goal of treatment is to normalize vitamin D levels to relieve symptoms and decrease the risk of fractures, falls, and other adverse health outcomes. To prevent vitamin D deficiency, the American Academy of Pediatrics recommends that infants and children receive at least 400 IU per day from diet and supplements. Evidence shows that vitamin D supplementation of at least 700 to 800 IU per day reduces fracture and fall rates in adults. In persons with vitamin D deficiency, treatment may include oral ergocalciferol (vitamin D2) at 50,000 IU per week for eight weeks. After vitamin D levels normalize, experts recommend maintenance dosages of cholecalciferol (vitamin D3) at 800 to 1,000 IU per day from dietary and supplemental sources.
PMID: 19835345 [PubMed - indexed for MEDLINE]
Clinical Context
Skeletal development, bone health, and neuromuscular function all require vitamin D. There are 2 forms of vitamin D: vitamin D2 (ergocalciferol), produced by irradiating ergosterol found in yeast and plants; and vitamin D3 (cholecalciferol), found in oily fish and synthesized in the skin in response to sunlight.
Because few foods contain vitamin D2, it is difficult to maintain adequate levels of vitamin D from dietary sources alone, and humans typically obtain 90% of vitamin D from sunlight. Because milk and other foods have been fortified with vitamin D, the rickets epidemic has subsided, but vitamin D deficiency and insufficiency are still linked to other pathologic conditions affecting persons of all ages.
Study Highlights
· Signs and symptoms of vitamin D deficiency develop slowly or are nonspecific.
· These may include symmetric low back pain in women, proximal muscle weakness, muscle aches, and throbbing bone pain.
· Vitamin D deficiency is defined as a 25-hydroxyvitamin D level of less than 20 ng/mL (50 nmol/L).
· Vitamin D insufficiency is defined as a serum 25-hydroxyvitamin D level of 20 to 30 ng/mL (50 - 75 nmol/L).
· To prevent vitamin D deficiency, infants and children should have vitamin D intake of at least 400 IU/day from diet and supplements.
· Unless infants are ingesting at least 1 L/day (33.8 fl oz) of vitamin D-fortified formula or milk, they should receive supplementation of 400 IU/day.
· Vitamin D supplementation, 400 IU/day, is recommended for all children and adolescents who do not get regular sunlight exposure, who do not consume 1 L/day or more of vitamin D-fortified formula or milk, or who do not take a daily multivitamin supplement containing at least 400 IU of vitamin D.
· In adults, vitamin D supplementation of 700 to 800 IU or more per day may reduce rates of falls and fractures.
· Contraindications to vitamin D supplementation include tuberculosis or other granulomatous diseases, metastatic bone disease, sarcoidosis, or Williams syndrome.
· Patients with vitamin D deficiency should receive oral ergocalciferol (vitamin D2), 50,000 IU per week for 8 weeks.
· Serum 25-hydroxyvitamin D levels should be checked when this 8-week course is completed, and if these levels are not at least 30 ng/mL, the most likely cause is nonadherence to therapy or malabsorption.
· A second 8-week course of ergocalciferol should be given if the level is not at least 30 ng/mL. Patients with suspected malabsorption may need gastroenterologic consultation.
· Once vitamin D levels normalize in patients who were deficient, patients should receive maintenance dosages of cholecalciferol (vitamin D3), 800 to 1000 IU per day from dietary sources and/or supplements.
· Because vitamin D is fat soluble, toxicity may result from excessive supplementation.
· Signs and symptoms of vitamin D toxicity may include headache, metallic taste, nephrocalcinosis or vascular calcinosis, pancreatitis, nausea, and/or vomiting.
Clinical Implications
· The diagnosis of vitamin D deficiency is often missed because the signs and symptoms develop slowly or are nonspecific, such as symmetric low back pain, proximal muscle weakness, muscle aches, and throbbing bone pain. Diagnosis of suspected vitamin D deficiency or insufficiency is confirmed with measurement of 25-hydroxyvitamin D levels.
In older adults, vitamin D supplementation of 700 to 800 IU per day is associated with a lower risk for falls and fractures. Suggested treatment in patients with vitamin D deficiency is oral ergocalciferol, 50,000 IU per week for 8 weeks. Adults with vitamin D deficiency, except for those with malabsorption syndromes, should receive maintenance dosages of 800 to 1000 IU of vitamin D per day. (Januari 2010)