Page 27 - Nutrinsight-4

NutrInsight • Satiety: News Insights
a reduction in ghrelin and an increase in PYY coincided with a reduction in self-reported energy intake in the prebiotic group. A decrease in body weight was observed with the OFS treatment, whereas the placebo group gained weight over the 12 weeks.
Short-term effects of prebiotics are interesting in healthy individuals. However, it is important to assess longer-term benefits in diseased patients with impaired metabolic status. It is known for example that the prebiotic effects of a high cereal fibre intake are associated with reduced risk for type-2 diabetes, but has little or no effect on glycemic control or glucose tolerance in clinical trials lasting 4-12 weeks. It might be that colonic adaptation to high fibre intake could take many months to produce effects with potential clinical relevance. To test this hypothesis, a one-year intervention was carried out in hyperinsulinemic adults who were randomly assigned to receive either a high-wheat fibre cereal (24 g/d) or a low fibre cereal [Freeland et al., 2010]. Whereas no difference in body weight was reported between groups, plasma GLP-1 after 12 months was higher in the high fibre cereal group than baseline values and higher than the control cereal. The data revealed that wheat fibre increased SCFA production and GLP-1 secretion in hyperinsulinemic humans, but these effects took 9-12 months to develop.
Conclusion
In conclusion, several experimental data suggest that the gut microbiota intervene in the regulation of neuro- endocrine function, and thereby may influence appetite and body weight control. The gut microbiota can be considered a novel nutritional target to control disorders of metabolism and/or food intake behaviour.
• Changing the gut microbiota with prebiotics, but also other fermentable CHo, modulates host endocrine function related to appetite and energy metabolism (increase in gut hormones gLP-1, Pyy, decrease in ghrelin, increase in leptin or leptin response, decrease in endocannabinoids, etc).
• The mechanisms of these effects remain unknown. They might have to do with gut microbiota composition, function, or act via short chain fatty acids or endocrine L-cell differentiation.
• Intervention studies in humans suggest that prebiotics and fermentable CHo may modulate the production of endogenous gastro-intestinal hormones affecting appetite/satiety (Pyy, gLP-1, ghrelin):
u Dose-dependent effects have been reported but the influence of concomitant effects of fermentable CHO present in food remains unknown,
u The relevance for long term adaptation of appetite (and body adiposity) requires further studies,
u The link with the gut microbiome and gut microbiota function (fermentation) remains to be established.
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Key Points