Modern studies on vitamin D place particular emphasis on the intake of the vitamin by the general population as low levels of Vitamin D are associated with serious health problems in later life. Vitamin D is a fat-soluble vitamin that can be obtained through diet or synthesized by the body after skin exposure to sunlight (UVB). People who do not get enough sun exposure usually choose to take a Vitamin D supplement as it is essential for bone and tooth health as well as for maintaining a healthy immune system. It is recommended for the elderly, especially for those with reduced nutrient intake or for people with little or no sun exposure.