Sunshine doesn't come in a bottle, and Vitamin D doesn't grow in a field. However, sunshine and vitamin D are both essential to the human body. Sunshine is a vital element, and Vitamin D is a hormone. Sunshine and sunlight are sometimes recognized as the other vitamin. Naturally there are many reasons to let the sunshine in: Sunlight brings strength to every living creature Sunlight is vitally important in the nutritive processes in both plant and animal life, as a necessary