Have you ever wondered why the B vitamins are numbered from 1 to 12, but there are only 8 of them? No? I'm always amazed at how little the average person knows/cares about the most directly relevant science to your life. One of my colleagues casually brought up vitamin D in a conversation that I overheard earlier today and I was so excited I almost wet myself.
As for the answer to the vitamin B conundrum, it's because the other 4 compounds are not considered essential, and thus do not meet the requirements for being a vitamin, as defined. Here is a normal website source. Two of the four non-essential B 'vitamins', adenine and inositol, are synthesized by human enzymes, and the other two, para-aminobutyrate and salycilate, are obtained from either plants or bacteria.
I'd like to do a more formal analysis of the B-vitamins at some point later, but the reason I brought it up this time is because... they're weird. Kind of random-looking for molecules that turn out to be essential for normal biochemical function, imo. I guess you could say that about a lot of vitamins, but these, in particular. The thumbnail image is vitamin B1, thiamine.
I only recently jumped on the Presearch bandwagon and I wish I had done it sooner. It's way better than Google.
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