Long term exposure to high protein diet or high fat diet have opposite effects on vagal afferent sensitivity to lumenal macronutrients and ip cholecystokinin

Abstract

Long term exposure to high fat (HF), high protein (HP) or high carbohydrates (HC) diets may lead to alterations of short term control of food intake, especially through their effects on peripheral sensitivity to gut hormones such as cholecystokinin and macronutrients. METHODS: Mice were submitted to either HF, HP or HC diet for 2 weeks. Neuronal activation was measured within the first central relay of vagal ascending fibers, the Nucleus of the Tractus Solitarius (NTS) in response to either intragastric gavage of calibrated diet load or peripheral injections of increasing doses of CCK. NTS activation was measured using immunohistochemical quantification of c‐fos expression performed on brainstem slices. RESULTS: We observed that HP‐induced NTS activation of HP adapted animals was greater than HF‐induced NTS activation of HF adapted animals. This result was consistent with a marked decrease in CCK sensitivity in HF adapted mice when compared to HP adapted mice. CONCLUSIONS: This study suggests that adaptation to HP diet increases sensitivity to gut anorectic signals whereas HF diet supresses this effect.

A high-protein diet for reducing body fat: mechanisms and possible caveats

“…Diets high in protein will elevate concentrations of plasma amino acids [ 54 ]. According to Nefti et al high intake of protein induces a vagal feedback to the satiety center of the nucleus tractus solitarius in the brainstem and the hypothalamus to suppress hunger [ 55 ]. Poppitt et al [ 56 ] showed that the satiating effect after a high-protein preload was significantly larger than preloads containing an iso-energetic amount of carbohydrates or fats.…”