Vitamin D is a trace substance and must be produced or ingested in a certain quantity to ensure balanced, good health.
In an ideal world, summer’s end your stock of vitamin D as they will have attained a high enough level to get you through the winter, but for an increasing number of the public, that may not be the case.
Vitamin D is a trace substance and must be produced or ingested in a certain quantity to ensure balanced, good health. As with other vitamins, a deficiency results in a specific bone disease, in this case osteomalacia, or in severe cases rickets. Vitamin D is unique in that it is more like a hormone activator and we are designed to make it ourselves with help from the sun. Ultraviolet B light waves (UVBs) activate the skin to make this vitamin form as a type of cholesterol. This is then changed in the liver before being converted into its active form in the kidneys and several other tissues, including breast, prostate and bowel.
The main article is an extensive look at vitamin D myths and facts.