At the second PreProSim — Brazilian Congress on Pre, Pro and Synbiotics –, several sessions on June 16th covered the topic of metabolic disorders and obesity.
Koen Venema says transplant studies show the microbiota can induce obesity. He introduced a review on the topic of gut microbiota as the link between obesity and adipose tissue, and noted that there are conflicting findings in the literature.
Venema went on to discuss the effects of prebiotics on metabolism. Studies from the Cani Lab have shown that Fructooligosaccharides (FOS) increase GLP1 in the proximal colon in rats. In healthy humans, FOS increase fermentation and plasma PYY and GLP1, and decrease post-prandial glucose. In obese humans, FOS modulate PYY, blunt ghrelin response, and improve glycemic control.
Venema concluded this topic by illustrating that FOS impact GLP2 and the endocannabinoid system. More research is needed for insight into the mechanisms.
Next, Venema discussed the effects of probiotics on metabolic risk markers, including studies that have found:
Venema says all effects are strain dependent, rendering a meta-analysis ambiguous. He cautioned that transfer of mouse observations to humans are not systematic.
Finally, he called attention to the lack of data on synbiotics in obesity and metabolic syndrome.
This talk focused on how obesity can lead to diabetes. Essentially, a certain diet leads to more glucose and lipids, which results in liver fat tissue and liver fat accumulation. Fat tissue disseminates in the liver, muscle, and pancreas, favoring insulin resistance.
João Eduardo Nunes Salles posed the question: what determines fat distribution? He noted a study that discussed a “metabolically benign” type of obesity in humans. A 2014 review in NEJM discussed the role of ectopic fat in insulin resistance, dyslipidemia, and cardiometabolic disease. He also discussed how inflamed macrophages proliferate in adipose tissue and cause inflammation.
Tappenden says there are three requirements for prebiotics: they must resist digestion, be fermented, and benefit the host. She noted that not all dietary fibres are prebiotics.
Benefits of prebiotics noted in the literature include reducing the prevalence and incidence of infections, reducing inflammation and symptoms, exerting protective effects on colon cancer, and promoting satiety and weight loss (via stimulated GLP1).
Dose matters, but very few studies compare different kinds of prebiotics: galactooligosaccharides (GOS) to FOS to inulin.
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