Why is vitamin D still called a vitamin?

In casual conversation, vitamin D can be mis-heard as B, so I always add, ‘vitamin D–the sunshine vitamin’. I always make this association with sunshine because it’s the most natural way we get it. Because our skin can make so much in so little time, it functions like leaves converting light, water and soil into more trees. read more

In 1969, after studying nuclear fragments of intestinal cells, a specific binding protein for Vitamin D called the Vitamin D Receptor was identified by Mark Haussler and Tony Norman. In 1971–72, the further metabolism of vitamin D to active forms was discovered. In the liver, vitamin D was found to be converted to calcifediol. read more