I’ve said it before and I’ll probably say it again, the bacteria in your gut controls everything…
There was recently a paper published that caught my attention. The title says it all, “Host Remodeling of the Gut Microbiome and Metabolic Changes During Pregnancy.“
What the data shows is that, during pregnancy, there are changes to the mother’s gut-associated bacteria between the first and the third trimester. The bacteria during the first trimester are fairly “normal” and contain a high diversity of bacterial species. During the third trimester, several types of bacteria, notably the very inflammatory Proteobacteria become elevated. Interestingly, there are a large number of studies which show that elevated Proteobacteria levels are associated with screwed up metabolism of the host resulting in obesity, diabetes, etc most likely because of excessive inflammation.
What was REALLY cool (at least to a nerd like me) is that when the scientists transferred the bacteria from a third-trimester mom into a germ-free mouse (Think of it as a mouse that lives in a sterile bubble), those animal became fatter and less sensitive to insulin signaling than mice given bacteria from a first-trimester mother.
What this means is that one of the main reason’s why pregnant women gain weight and adiposity during pregnancy is BECAUSE of changes to the bacteria that reside in their gut. The study above went on to show that the bacteria that emerges during pregnancy is better able to extract energy from the diet and transfer that to the mother, and therefore the baby as well. The downside of this is the extra-weight gain and potentially gestational diabetes as a result…
You have to ask yourself, why would you want this to happen during pregnancy? You would think that you’d want Mom to be as healthy as possible and to not have a screwed up metabolism, never mind diabetes, right???? WRONG!
There is a strong hypothesis that during pregnancy, the mothers body is willing to sacrifice its own sensitivity to sugar/gluces so that energy is diverted to the developing baby. Evolutionarily, it makes sense to put that cute little parasite (that you’ll eventually come to love) first.
Its amazing the balance that the host and microbiota have and how they can affect each other. In this scenario basically what we have is the following:
1) Some unknown change in the mother that results in a slow alteration of the microbiota between the first and third trimester.
2) These altered microbiota produce more energy from the consumed food which can be transferred to the host.
3) The third trimester microbiota are also way more inflammatory…
4) The inflammation driven by the altered microbiota has been shown to play a CRITICAL roll in decreasing insulin sensitivity, which in this case is beneficial in diverting energy to the developing baby.
What an absolutely beautiful symbiotic set of events.