title: Variability of the methionine loading test: no effect of a low protein diet.
abstract: The methionine loading test is used for the diagnosis of impaired methionine/homocysteine metabolism, in particular the transsulfuration pathway. Usually this test is performed on a low protein diet to control the intake of methionine. However, this is inconvenient and relatively expensive. In this study we compared the effects of a low protein diet and a standard diet on methionine loading test in 28 subjects (crossover design). The mean difference in homocysteine concentration after methionine loading between the two diets was 1.3 [confidence interval (CI) 95%-1.0-3.6] mumol/L which demonstrates that a special low protein diet is not essential in the performance of the methionine loading test. We also observed that 3 weeks after the first methionine loading test, fasting serum concentration of folate was higher and vitamin B12 concentration was lower.
authors.affiliation: Department of Hematology, Municipal Hospital Leyenburg, The Hague.
authors.forename: M
authors.initials: M
authors.lastname: den Heijer
authors.forename: G M
authors.initials: GM
authors.lastname: Bos
authors.forename: I A
authors.initials: IA
authors.lastname: Brouwer
authors.forename: W B
authors.initials: WB
authors.lastname: Gerrits
authors.forename: H J
authors.initials: HJ
authors.lastname: Blom
mesh_terms: D000328:Adult; D000592:Amino Acid Metabolism, Inborn Errors / Q000175:diagnosis*; D004044:Dietary Proteins / Q000008:administration & dosage*; D005260:Female; D006710:Homocysteine / Q000378:metabolism; D006801:Humans; D008297:Male; D008715:Methionine / Q000378:metabolism; D008875:Middle Aged
chemical_list: D004044:Dietary Proteins; D006710:Homocysteine; D008715:Methionine