The human gut microbiome is a critical component of digestion


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The critical contributions of the gut microbiota toward human digestion have just begun to be elucidated. Particularly, more recent research is revealing how the impacts of microbial metabolism extend beyond the GI tract, denoting the so-called gut-brain (e.g., biogenic amines acting as neurotransmitters) [182], gut-liver (e.g., alcohols) [183], gut-kidney (e.g., uremic toxins such as cresyl sulfate) [135], and gut-heart (e.g., trimethylamine) [184] axes. The primary focus to date has been on the SCFAs derived mainly from complex carbohydrates, and crucial knowledge gaps still remain in this area, specifically on how the SCFAs modulate glucose metabolism and fat deposition upon reaching the liver. However, the degradation of proteins and fats are comparatively less well understood. Due to both the diversity of metabolites that can be yielded and the complexity of microbial pathways, which can act as a self-regulating system that removes toxic by-products, it is not merely a matter of such processes effecting health positively or negatively, but rather how they are balanced. Further, the presentation of these substrates to the gut microbiota, as influenced by the relatively understudied host digestive processes occurring in the small intestine, is equally important. Future work could therefore aim to determine which of these pathways are upregulated and downregulated in disease states, such as autism and depression (gut-brain), NAFLD (gut-liver), chronic kidney disease (gut-kidney), and cardiovascular disease (gut-heart). Further, a combination of human- and culture- (in vitro and in vivo) based studies could resolve the spectrum of protein and fat degradation present among healthy individuals, in order to further our understanding of nutrient cycling in gut microbial ecosystems, and thus gain a necessary perspective for improving wellness.

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Vince, Any practical advice? I tend to moderate my carbohydrate, but specifically eat around 100g of white potato every couple of days that I first cook and then cool, reheat when cold and then eat. This is supposed to modify the starch so that it is available for further metabolism by the gut, and so form a pre-biotic. No gut issues in the last 2 years I've been doing it.


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Quoted From JennVsDiabesity: Dr. Danenberg, Dr. Davis advocates about 20g of prebiotic fibers each day to feed the gut microbiome. I’m wondering if you still eat any prebiotic fibers of some sort while eating a carnivore diet? What does the gut microbiome look like with a carnivore diet? Is it as healthy?

Jenn: This is so interesting and surprising at the same time for me. I do not eat fiber from plants. However, I do eat about 1-2 teaspoons of raw Manuka Honey daily, which has some oligosaccharides as a prebiotic. Also, there is some fiber in animal products, but very little. However, I have daily bowel movements with good form. (Am I getting too descriptive?)

When I dug into the science of the gut microbiome, I found that the garden of gut bacteria can efficiently produce short chain fatty acids, which are required for health, from fiber as well as amino acids. That was an eye-opener for me. Here is a Table that details this fact: Macronutrient metabolism by the human gut microbiome: major fermentation by-products and their impact on host health This table was published in this 2019 article:

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