Did you ever wonder why there is no Vitamin B4 on the list anymore? Also, is it possible that some nutrients lose their "Vitamin" title? The histories of choline and adenine—the two substances once known as Vitamin B4—show just how much our understanding of health has changed. Before I write about why these two are important for our wellbeing, I wanted to share a bit of their history. If you are not much of a history person, just scroll past this part. Let's start with the st