Page 24 - Nutrinsight-4

NutrInsight • Satiety: News Insights
Gut hormones and appetite
In obese animals, ITF are able to modulate gastrointestinal peptides involved in the control of food intake, namely the satiety-associated GLP-1 (7-36) amide and ghrelin, a hormone that stimulates intake. After three weeks of treatment with either a standard diet or the same diet enriched with the prebiotic oligofructose (OFS), an increase in anorexigenic peptides PYY and GLP-1 (7-36) amide and a decrease in the orexigenic hormone ghrelin occurred [Cani et al., 2004]. Dietary energy intake throughout the experiment was lower in OFS fed animals, leading to a significant decrease in epidydimal fat mass at the end of treatment. These observations demonstrate the potential modulation of GLP-1 (7-36) amide and ghrelin by fermentable fibres such as fructans, which are rapidly and extensively fermented in the proximal part of the colon. The addition of OFS in the diet prevented the promotion of energy intake, body weight gain, fat mass development, and serum triglyceride accumulation induced by the high-fat content. A lower ghrelin level was also observed.
The crucial role of GLP-1 in the effects of OFS has been evidenced in mice studies using the GLP-1 receptor antagonist exendin 9-39 (Ex-9) that blocks GLP-1 receptor functionality. Figure 2 presents the results of a study of the influence of prebiotics on food intake, body weight gain, and hepatic insulin sensitivity under various dietary conditions in high-fat fed diabetic mice treated with OFS for four weeks in the presence or absence of Ex-9 [Cani et al., 2006b]. OFS improved glucose tolerance, fasting blood glucose, glucose- stimulated insulin secretion, and insulin sensitive hepatic glucose production and reduced body weight gain. Ex-9 totally prevented the beneficial effects of OFS, demonstrating the key role of a functional GLP-1 receptor.
(a) 76 a a a a
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WT HF-CT
WT HF-OFS
Figure 2: Total body weight (a) and energy intake (b) in diabetic (HF), wild-type (WT) or gLP-1 receptor knockout (gLP-1R-/-) mice treated for 28 days with or without (CT) oFS or oFS plus Ex-9 (oFS-Ex). Data are mean ± S.E.M.
Data with differing superscript letters are significantly different (p<0.05).
Source: Cani et al., 2006b
WT HF-OFS-Ex
GLP-1R -/- HF-CT
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WT HF-CT
WT HF-OFS
GLP-1R -/- HF-OFS
WT HF-OFS-Ex
GLP-1R -/- HF-CT
GLP-1R -/- HF-OFS
Total energy intake (kcal) Total body weight gain (g)