Effects of Vitamin D on Human Body and the Measurement Methods: A Systematic Review

Vitamin D is a fat-soluble metabolite, which can be mainly obtained from skin exposure to the sunlight. Foodstuffs containing vitamin D such as oily fish, eggs, and mushrooms are other sources for this vitamin. Vitamin D plays its role in the body via its intracellular receptor. The discovery of vitamin D receptors on a wide range of body tissues indicates the broad effects of this metabolite on the human body. The aim of this study was to investigate vitamin D mechanisms and measurement methods.

In this study, out of 72 primary articles searched in PubMed and Google Scholar databases from  2012 to 2017, 16 articles with the keywords vitamin D, gold-standard methods, pharmaceutical forms, and body organs were selected and studied.  

Studies have shown the effects of vitamin D on almost all body organs, including skin, bone, liver, intestine, and muscles. Some hormonal functions are also correlated with vitamin D. Since vitamin D deficiency may interfere with numerous mechanisms in the body, taking vitamin D supplements would have significant effects on preventing many diseases.  

 As vitamin D deficiency is quite common worldwide, it is recommended to measure vitamin D levels annually and to take vitamin D supplements under the supervision of a physician. The reference method used for vitamin D concentration assessment is liquid chromatography-tandem mass spectrometry. Other measurement techniques have also been used in order to quantify this metabolite, such as immunoassays and chemiluminescence assays.