D vitamini: Yapısı, Sentezi ve Çeşitli Hastalıklardaki Önemi

Year 2019, Volume: 1 Issue: 1, 1 - 6, 01.03.2019

Eda Pelin Terli Firdevs Mutlu Can Uluçay N.irem Kılıç Mine Akkır Olcay Atılgan Enes Özgün Selda Kabadere

Abstract

Vitaminler vücudumuzda çeşitli biyokimyasal işlevler için gereklidirler. D vitamini, yağda çözünen ve depolanabilen vitamin grubunda olup hormona benzer birçok göreve sahiptir. D vitamini organizmada sınırlı olarak üretilip depolanmaktadır; güneşten gelen ultraviyole B ışınları en güçlü kaynağı oluşturmaktadır. D Vitamini deride yaz aylarında güneşin ultraviyole ışığının etkisiyle sentezlenir veya gıdalardan, özellikle de yağlı balıklardan elde edilir. Yeterince ultraviyole ışını alamamak ve deriyle temasının engellenmesi D vitamini sentezinin yetersiz olmasına neden olmaktadır. Sentezinde önce karaciğerde 25-hidroksivitamin D [25(OH)D]’ye sonra böbrekte 1,25-dihidroksivitamin D [1,25(OH)2D]’ye dönüştürülür; sadece aktif metabolit hücreye girebilir ve D vitamini reseptörüne bağlanabilir. Ardından kalsiyum bağlayıcı protein gibi duyarlı bir gen üzerinden etkisini gösterebilir. 1,25(OH)2D üretimi paratiroid hormonu tarafından uyarılır ve kalsiyum miktarı arttığında azalır. D vitamini araştırmalarındaki son gelişmeler, kas-iskelet sistemi dışındaki birçok vücut sistemi üzerinde faydalı etkilere sahip olduğunu göstermektedir. Ayrıca son yıllarda elde edilen bilgiler, D vitamini yetersizliğinin kanser, diyabetes mellitus ve multipl skleroz gibi otoimmün hastalıklar, kardiyovasküler hastalıklar, obezite ve şizofreni görülme sıklığını arttırdığını ortaya koymaktadır. Dolayısıyla, sağlık için çok önemli görevlere sahip bu vitaminin yeterli miktarda alınamaması ciddi sağlık problemlerine neden olabilmektedir. Ayrıca güneş gören bir coğrafyada bulunmamıza rağmen maalesef toplumumuzda D vitamini düzeyinin genel olarak düşük olduğu görülmektedir. Sonuç olarak, optimum D vitamini düzeyine sahip olmak sadece kemik sağlığı açısından değil genel sağlık durumunun sürdürülebilmesi için de son derece önemlidir.

Keywords

1, 25 dihidroksikolekalsiferol

Vitamin D: Structure, Synthesis and İmportance in Various Diseases

Abstract

Vitamins are required for various biochemical functions in our body. Vitamin D is fat-soluble and can be stored; it has similar functions to hormones. Vitamin D is produced and stored as limited in the organism; The ultraviolet B rays from the sun constitute the strongest source. Vitamin D is synthesized in the skin by the action of the sun's ultraviolet light in summer or is derived from foods, especially fatty fish. Inadequately receiving ultraviolet rays and preventing contact with the skin causes inadequate vitamin D synthesis. After hydroxylation in the liver into 25-hydroxyvitamin D (25(OH)D) and kidney into 1,25-dihydroxyvitamin D (1,25(OH)2D), the active metabolite can enter the cell, bind to the vitamin D-receptor and subsequently to a responsive gene such as that of calcium binding protein. The production of 1,25(OH)2D is stimulated by parathyroid hormone (PTH) and decreased by calcium. Recent advances in vitamin D research indicate that this vitamin has beneficial effects on several body systems other than the musculoskeletal system. Moreover, the information obtained in recent years suggests that vitamin D deficiency increases the incidence of autoimmune diseases such as cancer, diabetes mellitus and multiple sclerosis, cardiovascular diseases, obesity and schizophrenia. Therefore, inadequate intake of this vitamin with very important functions for health can cause serious health problems. In addition, although we are in a sun-facing geography, unfortunately our society has low levels of vitamin D in general. As a result, having an optimum vitamin D level is important not only for bone health but also for maintaining a general health condition.

Keywords

1, 25 dihydroxycholecalciferol

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