title: Dietary cysteine alleviates sucrose-induced oxidative stress and insulin resistance.
abstract: Diets that promote oxidative stress favor impairment in glucose homeostasis. In this context, increasing the cysteine intake may be beneficial by maintaining glutathione status. We have investigated the effects of dietary cysteine on oxidative stress and glucose homeostasis in rats fed a high-sucrose (HS) diet. Rats were assigned for 6 weeks to a standard diet or to HS diets in which the protein source was either an alpha-lactalbumin-rich whey concentrate (a cysteine-rich protein) or the total milk proteins alone or supplemented with 5.8 or 20 g N-acetylcysteine per kilogram of food. Increasing the cysteine intake prevented HS-induced oxidative stress, as assessed by blood and tissue glutathione and carbonyl levels. At the same time, the HS-induced glucose intolerance, impaired postprandial glycemic control, and decrease in muscle and liver insulin-induced activation of insulin receptor substrate 1 and Akt were prevented by increasing the level of dietary cysteine, a major original finding. Of great interest was the observation that all beneficial effects of cysteine supplementation were duplicated by the consumption of a cysteine-rich protein. These data show that increasing the cysteine intake limits HS-induced impairment of glucose homeostasis and suggest that these effects are mediated by a reduction in oxidative stress.
authors.affiliation: INRA, AgroParisTech, UMR914, Nutrition Physiology and Ingestive Behavior, CRNH-IdF, F-75005, Paris, France.
authors.forename: Clémence
authors.initials: C
authors.lastname: Blouet
authors.forename: François
authors.initials: F
authors.lastname: Mariotti
authors.forename: Dalila
authors.initials: D
authors.lastname: Azzout-Marniche
authors.forename: Véronique
authors.initials: V
authors.lastname: Mathé
authors.forename: Takashi
authors.initials: T
authors.lastname: Mikogami
authors.forename: Daniel
authors.initials: D
authors.lastname: Tomé
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Huneau
mesh_terms: D000818:Animals; D001483:Base Sequence; D003545:Cysteine / Q000008:administration & dosage*; D017931:DNA Primers; D004032:Diet; D005247:Feeding Behavior / Q000187:drug effects; D005951:Glucose Tolerance Test; D005978:Glutathione / Q000378:metabolism; D006128:Growth; D007328:Insulin / Q000378:metabolism; D007333:Insulin Resistance; D008297:Male; D018384:Oxidative Stress / Q000187:drug effects*; D016133:Polymerase Chain Reaction; D019518:Postprandial Period; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction; D013395:Sucrose / Q000494:pharmacology*
chemical_list: D017931:DNA Primers; D007328:Insulin; D013395:Sucrose; D005978:Glutathione; D003545:Cysteine