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TOP 10 TAKEAWAY MESSAGES:
Microbiome
1. The microbiome is a collection of micro-organisms; microbiota are
the organisms themselves.
2. The human organism has ~10 trillion human cells. The human gut
is colonized by ~100 trillion cells (bacteria, fungi, and viruses).
3. Among gut bacteria species, over 90% are anaerobic that utilize
the substrate of sloughed intestinal cells, plant polysaccharides,
starch cellulose, and bile components.
4. The phyla Gram-positive Firmicutes and Gram-negative
Bacteroidetes make up about 90% of the bacteria in the large
intestine. In patients with obesity, Firmicutes is proportionally
increased compared to Bacteroidetes.
5. Some intestinal bacteria promote increased density of small
intestinal villi capillaries and more efficient absorption of
nutrients than other bacteria; Gram-positive Firmicutes may
more efficiently extract calories from carbohydrates than Gram-
negative Bacteroidetes in patients with obesity.
6. Some intestinal bacteria may also facilitate central nervous
system and other body organ signaling that may influence energy
balance.
7. Intestinal bacteria can also influence bile acid metabolism and gut
hormone secretion, both of which can affect energy balance.
8. Bariatric surgery may alter the microbiome and reduce the
efficiency of extracting calories from consumed carbohydrates.
9. Individuals with overweight or obesity may not benefit from
microbiota that promote more efficient absorption of nutrients.
10. The effects of fecal transplant in humans with obesity differ
compared to rodents, with some fecal microbiota transplantation
to patients (humans) with obesity not leading to a reduction in
body mass index, despite successful and sustained changes in
the intestinal microbiome and bile acid profiles similar to the lean
donor.
