High-Fat Meals, the Gut’s Endocrine System and Bacteria

As you know, there are certain topics that are of particular interest to me including autism; Parkinson’s; -omes, other than just the bacterial microbiome; neglected illnesses like chronic fatigue and fibromyalgia; obesity; etc.; and of course, diet and its relationship to the organisms of the biome and health.  A short post today about a research out of Duke University, looking at how a high fat diet affects the gut and its contents.[i]

One thing I haven’t had much opportunity to write about is the endocrine (hormone) system of digestive system, simply because I really haven’t seen much about it and its interaction with the gut bacteria.  The scientists noticed, in zebrafish, that these endocrine cells (in the gut, they are referred to as entereoendocrine cells and they are found in the mucosal lining), which normally send signals to brain and body by releasing hormones, shut down for a number of hours after a high fat meal.  Ordinarily, the hormones they produce tell the body about gut movement, fullness, digestion, nutrient absorption, insulin sensitivity and energy shortage.  However, after encountering high fat food, they shut down for several hours – and no one has a clue why.

There are several possibilities.  A possible negative view: one of the authors states, “Since enteroendocrine cells are key players in digestion, the feeling of being full and subsequent feeding behavior, this silencing may be a mechanism that somehow causes people eating a high-fat diet to eat even more….If this happens every time we eat an unhealthy, high-fat meal, it might cause a change in insulin signaling, which could, in turn contribute to the development of insulin resistance and Type 2 diabetes.”

Inside cells are multiple organelles (their version of organs), including one called the endoplasmic reticulum, in which new proteins (like neurotransmitters and hormones) are synthesized.  This organelle appears to undergo stress when the cells are confronted with a high-fat meal, and become overstimulated and then exhausted.  For a time then, the cells are silenced – they cannot communicate with the rest of the body at all.

What’s even more interesting is that in germ-free fish, this does not happen.  In fact, the researchers were able to narrow down and isolate the specific bacteria that causes this effect:  Acinetobacter.  This is a really rare (les than .1% of the gut bacteria), but after a high-fat meal, they increase 100-fold.

At this point, the scientists don’t even know yet if it’s a good or a bad thing.  It’s possible that it’s a “maladaptive response to high-fat foods” ultimately leading to metabolic disorders.  On the other hand, it is “…also possible that the silencing is a beneficial adaptation to protect the animal from over-stimulation of the gut cells.”

Considering the incredibly dramatic increase in metabolic disorders and obesity in the last 3 decades, figuring out this kind of thing is incredibly important.  I’ll watch for updates.

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[i] https://today.duke.edu/2019/12/fatty-meal-interrupts-gut%E2%80%99s-communication-body-why