title: Effects of chronic dietary exposure to monosodium glutamate on feeding behavior, adiposity, gastrointestinal motility, and cardiovascular function in healthy adult rats.
abstract: BACKGROUND
  Monosodium glutamate (MSG) is a flavor-enhancer widely used as a food additive. However, its safe dietary concentration and its toxicity, including its possible implication in the recent metabolic syndrome pandemia, is still a controversial issue. Therefore, a deep knowledge of its effects upon regular dietary use is needed. Our aim was to evaluate the effects of chronic exposure to MSG on feeding behavior, abdominal fat, gastrointestinal motility, and cardiovascular function in rats.
  
  
  METHODS
  Two groups of adult male Wistar rats were used: control and treated with MSG (4 g/L in drinking water) for 6 weeks. Different functional parameters were determined and the histological structure was analyzed in tissues of interest.
  
  
  RESULTS
  Compared to control animals, chronic MSG increased water intake but did not modify food ingestion or body weight gain. Neither the abdominal fat volume nor the fat fraction, measured by magnetic resonance imaging, was modified by MSG. Monosodium glutamate did not alter general gastrointestinal motility, but significantly increased the colonic response to mechanical stimulation. It slightly reduced endothelium-dependent relaxation in aorta, without significantly modifying any other cardiovascular parameters. No significant histological alterations were detected in salivary glands, intestinal wall, aorta, heart, and kidney.
  
  
  CONCLUSIONS
  Chronic treatment with MSG in the adult rat increased water intake. This supports its potential to improve acceptance of low-fat regimens and to increase hydration in the elderly and sportspeople, often at risk of dehydration. Changes in colonic contractility and cardiovascular function could have some long-term repercussions warranting further research.
authors: Área de Farmacología y Nutrición y Unidad Asociada al Instituto de Química Médica(IQM) y al Centro de Investigación de Alimentos (CIAL) del Consejo Superior de Investigaciones Científicas (CSIC), Universidad Rey Juan Carlos, Alcorcón, Madrid, Spain.
authors: V
authors: V
authors: López-Miranda
authors: Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain.|CIBER de Salud Mental (CIBERSAM), Madrid, Spain.
authors: M L
authors: ML
authors: Soto-Montenegro
authors: Área de Histología y Anatomía Patológica y Unidad Asociada al Centro de Investigación de Alimentos (CIAL), Universidad Rey Juan Carlos, Alcorcón, Madrid, Spain.
authors: J A
authors: JA
authors: Uranga-Ocio
authors: Área de Farmacología y Nutrición y Unidad Asociada al Instituto de Química Médica(IQM) y al Centro de Investigación de Alimentos (CIAL) del Consejo Superior de Investigaciones Científicas (CSIC), Universidad Rey Juan Carlos, Alcorcón, Madrid, Spain.
authors: G
authors: G
authors: Vera
authors: Área de Farmacología y Nutrición y Unidad Asociada al Instituto de Química Médica(IQM) y al Centro de Investigación de Alimentos (CIAL) del Consejo Superior de Investigaciones Científicas (CSIC), Universidad Rey Juan Carlos, Alcorcón, Madrid, Spain.
authors: E
authors: E
authors: Herradón
authors: Área de Farmacología y Nutrición y Unidad Asociada al Instituto de Química Médica(IQM) y al Centro de Investigación de Alimentos (CIAL) del Consejo Superior de Investigaciones Científicas (CSIC), Universidad Rey Juan Carlos, Alcorcón, Madrid, Spain.
authors: C
authors: C
authors: González
authors: Área de Farmacología y Nutrición y Unidad Asociada al Instituto de Química Médica(IQM) y al Centro de Investigación de Alimentos (CIAL) del Consejo Superior de Investigaciones Científicas (CSIC), Universidad Rey Juan Carlos, Alcorcón, Madrid, Spain.
authors: C
authors: C
authors: Blas
authors: Área de Farmacología y Nutrición y Unidad Asociada al Instituto de Química Médica(IQM) y al Centro de Investigación de Alimentos (CIAL) del Consejo Superior de Investigaciones Científicas (CSIC), Universidad Rey Juan Carlos, Alcorcón, Madrid, Spain.
authors: M
authors: M
authors: Martínez-Villaluenga
authors: Unidad del Dolor, Servicio de Anestesiología, Hospital General Universitario Gregorio Marañón, Madrid, Spain.
authors: A E
authors: AE
authors: López-Pérez
authors: Dept. Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Madrid, Spain.
authors: M
authors: M
authors: Desco
authors: Área de Farmacología y Nutrición y Unidad Asociada al Instituto de Química Médica(IQM) y al Centro de Investigación de Alimentos (CIAL) del Consejo Superior de Investigaciones Científicas (CSIC), Universidad Rey Juan Carlos, Alcorcón, Madrid, Spain.
authors: R
authors: R
authors: Abalo
mesh_terms: D050154:Adiposity / Q000187:drug effects*; D000818:Animals; D002319:Cardiovascular System / Q000187:drug effects*; D004032:Diet; D004326:Drinking / Q000187:drug effects; D005247:Feeding Behavior / Q000187:drug effects*; D005421:Flavoring Agents / Q000633:toxicity*; D005769:Gastrointestinal Motility / Q000187:drug effects*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012970:Sodium Glutamate / Q000633:toxicity*
chemical_list: D005421:Flavoring Agents; D012970:Sodium Glutamate
keywords: MSG; cardiovascular function; fat; gastrointestinal motility; monosodium glutamate