How could our intestinal bacteria affect our sleep? The bacteria actually make chemicals that we steal from them in order to sleep normally; those chemicals are called the B vitamins. (And, those of you who don’t like vitamins and are about to skip this part, you do need to understand this or you will never sleep normally, or fix your headaches, or get out of your doctor’s office.)
The B vitamins are 8 chemicals that our bodies are unable to make. They were first discovered as bacterial “growth factors”, chemicals that had to be added to the petri dish to grow bacteria. Bacteria had just been discovered and scientists were experimenting with how many different types of bugs they could find and name after themselves. Just like making beer or bread, the recipe had to be just right. They discovered that the same yeast preparation we cooked with would encourage specific bacteria to grow. There were actually bacteria already in the yeast preparation, and those bacteria were making chemicals that other bacteria liked and needed.
Eventually the scientists figured out that our human cells needed these “growth factors” too. We couldn’t live without them but we couldn’t make them ourselves. (Which a bit odd when you think about it, every cell in our body needs this chemical to run properly but we can’t make it ourselves? Sort of bad planning!) For humans they called these chemicals “vitamins”, instead of growth factors. Once they got around to purifying the different chemicals they started naming them the “B’s” because they came after vitamin A was named.(duh!) Several chemicals were eventually grouped together as “B vitamins”, partly because some came from the same yeast broth, partly because they were all water soluble but also because they seemed to need each other to do their jobs. There were originally more than 8 (thus cyanocobalamin was named B12) but some, B4, B8, B10 and B11 that were originally numbered eventually lost their status as “vitamins” because it turned out we could make them ourselves after all, so now there are only 8 B vitamins. They are numbered and named, which makes the whole thing very, very confusing! Thiamine is B1, riboflavin B2, niacin B3, pantothenic acid B5 , pyridoxine B6, biotin B7, folate B9, and cyanocobalamin B12. You do not need to memorize this, you just need to know that they were meant to come together as an “eight-pack”, the 8 chemicals work together. We learned about how these chemicals work together from the study of bacteria. Bacteria need these chemicals to make energy and grow, just like we do, and there are certain bacterial species that can make some of them but not all of them. The only one we can make ourselves but is still considered a vitamin is niacin (if we have protein in our diet we can make niacin from tryptophan).
The first microbiologists (study of tiny, living things) found that there were bacterial species that could make riboflavin, B2. The bacteria made it for their own use but also released it into their surroundings. Next, they discovered that the riboflavin-producing bacteria wouldn’t grow by itself in a petri dish because it couldn’t make folate, B9. But if there was a second type of bacteria, that did make folate (but couldn’t make riboflavin), and the two were grown together, they could trade riboflavin for folate and both would be happy. Because of their shared needs the two types of bacteria appeared together and were said to have a “commensal” relationship; they each benefited from the presence of the other.
Now, back to our intestinal bacteria……The reason why the same foursome of bacterial species is found in every human with a “healthy gut” all over the world, is because each of the four makes at least one B vitamin and needs other B vitamins that the other three make and share. In other words, they need each other. They are a “commensal foursome”. And, they are secreting those vitamins into our intestine, making a sort of “B vitamin soup”. Picture all those little bacteria happily growing in their vitamin soup, which happens to be inside us! Why did they desert us? They were so happy in there, and we needed them! They deserted us because we stopped giving them what they needed from us, they need our vitamin D. We give them vitamin D, they give us B vitamins, everybody wins, we’re both thriving and happy! We had a commensal relationship with the bacteria in our intestine. Then, oops….. we go inside, stop making vitamin D on our skin from the sun and we can no longer provide our side of the bargain. The good guys are now slowly replaced by bacteria that don’t need vitamin D. Now we have the “wrong” bacteria and all the bad things associated with that “wrong” bacteria; irritable bowel syndrome, multiple allergies, or autoimmune diseases. The B vitamins don’t really come from the food, they come from the normal bacteria inside us. It has been that way since the first multi-celled organisms evolved with bacteria in their gastrointestinal track. There was never any reason for us to make the B vitamins because we always carried our source inside us!