Vitamin D is very important part of nutrition of the body. Naturally it produces in the skins of vertebrates when they expose to ultraviolet B rays either in form of sun light or in artificial light. Vitamin D regulates lot of functions of body including mood and anxiety, after undergoing different biochemical processes. It defends against microbial invaders thus increasing the immune system of the body. Vitamin D also regulates the calcium and phosphate concentration in bloodstreams. Vitamin D helps in growth and reformation of bones and healthy mineralization of the body. Five types of vitamin D have been discovered but two among them, Vitamin D2 & D3 are very crucial as far as human body is concerned. Volume of vitamin D in body is normally referred on 25 (OH)D status which should be more than 35ng/L in the blood of a normal body.

Vitamin D deficiency causes depression owing to the fact that it regulates the neuromuscular functions of the brain. There are many reasons for depression one of the major physical reason is deficiency of vitamin D. Different studies all over the globe determined the close relation between ‘vitamin D deficiency and depression'. The studies conducted in depression patients on different parts of the world show that the level of serum in depression patients was less than 35ng/L and in normal people the same was at an average of 46ng/L. This study clearly confirms the close relation of depression with vitamin D deficiency.

Another study revealed that the comparative ratio of depression was less in those areas where adequate sunlight exposure to the body was available than those areas where the same was not sufficient. If we talk about the depression in perspective of time then we will find that modernization, urbanization and industrialization have increased the ratio of depression. Along with many other reasons, vitamin D deficiency is one of the predominant factors because the modern life style has isolated us from exposure to sunlight which is the major source of production of vitamin D.

Our life style since later part of 20th century has changed such a way that we work in close places where exposure to sunlight is very low, we travel in glasses which block the ultraviolet B, and we live in the garden of high-rise buildings and manage very less time for sunbath. All these factors are causing vitamin D deficiency and subsequently depression.

Vitamin D deficiency and depression are very closely related to each other. This relation brings very dangerous results when depression escalates to a level where it causes diabetic, cardiovascular diseases and risk to cancer and severe influenza or asthma.