The essential nutrient class vitamin got its name from Polish-American biochemist Casimir Funk’s 1912 book “The Vitamines”. Funk proposed that four recently discovered chemicals, with the shared property that you get a disease of deficiency if you don’t eat enough, should be grouped together into a single class. His name suggestion vitamine was a portmanteau of “vital amines”, where vital is from Latin vīta, meaning “life”, and amine is the class of organic chemicals they all fall under.
As it turns out, not even all four of those chemicals (now known as vitamins B1, B3, C, and D) were actually amines. British biochemist Jack Drummond successfully proposed a spelling change to vitamin in 1920 to de-emphasize the misnomer once it was widely understood.
Today, Funk’s criteria for vitamins instead define the category of essential nutrients. That is, essential nutrients are chemicals required for human life that we need to ingest in order to get enough to survive. We’ve discovered many more of these since, so for convenience, vitamins are now considered a subcategory of essential nutrients. All of the current subcategories are:
- Essential nutrients that are chemical elements are minerals.
- Essential nutrients that are fatty acids are essential fatty acids (currently, we are only aware of omega-3 and omega-6).
- Essential nutrients that are amino acids are essential amino acids (of which there are nine).
- Essential nutrients that don’t fall into any other category are vitamins.
- Well, except for choline, which is currently none of the above as it was only proven essential in 1998. I feel like this classification scheme is a pretty good illustration of what tends to happen to the first discovered subgroup of a new concept.
It’s also worth noting that essential oils are unrelated to essential minerals or essential nutrients, instead earning their adjective for containing the essence (fragrance) of a material.
Vitamins are typically referred to by letter today because American biochemist Elmer McCollum described a newly-discovered vitamin with the placeholder name “fat-soluble factor A” in a 1913 paper. By analogy, biochemists started calling three of Funk’s proposed vitamins “water-soluble factor B”, “water-soluble factor C”, and “fat-soluble factor D”. The fourth, now known as niacin, was instead called vitamin PP, as it was determined to Prevent Pellagra. It was later renamed to B3 when it was classified a B vitamin.
(If, like me, you’ve idly wondered what happened to vitamins F through J, wikipedia has a handy table: https://en.wikipedia.org/wiki/Vitamin#Naming)