Vitamin D Deficiency: A Global Health Problem

Abstract

Vitamin D deficiency is present in approximately 50% of the world population and is mainly a consequence of reduced sun exposure (ultraviolet B radiation) of the skin that is needed for dermal vitamin D production. Dietary intake of vitamin D is usually too low to maintain a sufficient vitamin D status. It has been demonstrated over the last few years that most tissues and cells express the vitamin D receptor supporting the notion that vitamin D exerts various effects beyond its established role for maintenance of bone and skeletal health. Epidemiological data show that 25-hydroxyvitamin D levels, that are currently considered the best indicator of vitamin D status, are associated with various diseases, including cardiovascular, malignant and autoimmune diseases. However, the causality of these associations remains to be proven. Interventional trials are therefore urgently needed to elucidate whether vitamin D supplementation is useful for the prevention and/or treatment of various chronic diseases. Vitamin D supplementation has immense potential for the improvement of public health when considering the high prevalence of vitamin D deficiency and the easy, inexpensive and safe way in which vitamin D can be supplemented.