Plantago ovata husks-supplemented diet ameliorates metabolic alterations in obese Zucker rats through activation of AMP-activated protein kinase. Comparative study with other dietary fibers

SummaryBackground & aimsOur aim was to compare the effects of intake of diets supplemented with different dietary fibers, namely cellulose, methylcellulose or Plantago ovata husks, (insoluble, soluble non-fermentable, and soluble fermentable fiber, respectively), on the abnormalities clustered in the metabolic syndrome.MethodsAdult obese Zucker rats were distributed in four groups which were fed respectively a standard, a cellulose-supplemented, a methylcellulose-supplemented or a P. ovata husks-supplemented diet, for ten weeks.ResultsIncreased body weight, hyperlipidemia, hyperinsulinemia and hyperleptinemia, increased TNF-α and reduced adiponectin secretion by adipose tissue found in obese Zucker rats were significantly improved in obese rats fed the P. ovata husks-supplemented diet, together with a lower hepatic lipid content which parallels activation of the signaling pathway of AMP-protein kinase in the liver. The methylcellulose-supplemented diet reduced body weight, hyperlipidemia, circulating free fatty acids concentration and ameliorated adipose tissue secretion of adiponectin and TNF-α. Feeding with the cellulose-supplemented diet only reduced free fatty acids circulating levels.ConclusionsThe soluble dietary fibers essayed are more beneficial than insoluble fiber in the treatment of metabolic syndrome, being the soluble and fermentable the more efficient to improve metabolic alterations. Fermentation products of P. ovata husks must play an important role in such effects.