Dear Mr. Scientist,
Why are vitamins named with letters and numbers? Like for B12, what does B mean and what does 12 mean?
Vitamins can be quite confusing. Most vitamins are often not one specific compound but a class of chemicals with the same biological activity. Vitamin A, for example, actually refers to the compounds retinol, retinal and four carotenoids. Letters were assigned to vitamins according to the order in which they were discovered, so the very first vitamin isolated given the designation “Vitamin A”. Other vitamins include B, C, D, E and K. What happened to vitamins F-J? There used to be vitamins with these names, but they were either renamed or no longer considered vitamins.
One of the most confusing vitamins is Vitamin B. There are vitamins B1-B3, B5-B7, B9 and B12. Originally these were all thought to have the same function, which is why they were grouped together as Vitamin B. Further research has shown that they are each distinct vitamins, which is why they get their own number.
After four years of filling our pages with science, our “Mr. Scientist,” Michael Leitch is off to new science-filled adventures. Stay tuned next semester for our “Ask Ms. Scientist” column. Meanwhile, tweet @DC_Science or email firstname.lastname@example.org with your burning science questions.