Methionine kinetics in adult men: effects of dietary betaine on L-[2H3-methyl-1-13C]methionine

• Published in: The American journal of clinical nutrition Vol. 54; no. 2; pp. 386 - 394
• Main Authors: Storch, K.J, Wagner, D.A, Young, V.R
• Format: Journal Article
• Language: English
• Published: Bethesda, MD American Society for Clinical Nutrition 01.08.1991
• Subjects: ACIDE AMINE; ADDITIF ALIMENTAIRE; ADITIVOS ALIMENTARIOS; administration & dosage; Adult; ADULTE; ADULTOS; ADULTS; AGE GROUPS; AMINES; amino acid metabolism; AMINO ACIDS; AMINOACIDOS; AMMONIUM COMPOUNDS; analogs & derivatives; ANIMALS; BASIC BIOLOGICAL SCIENCES; BETAINA; BETAINE; Betaine - administration & dosage; Betaine - pharmacology; Betaine - urine; BIOCHEMICAL REACTION KINETICS; Biological and medical sciences; blood; blood plasma; CARBON 13; CARBON ISOTOPES; CARBOXYLIC ACIDS; CHEMICAL REACTIONS; CISTINA; college students; CYSTINE; Cystine - administration & dosage; DEUTERIUM; diagnostic use; DIET; dietary supplements; DISULFIDES; DRUGS; ELEVE; ESTUDIANTES; EVEN-ODD NUCLEI; Fundamental and applied biological sciences. Psychology; HOMBRES; HOMME; Humans; HYDROGEN ISOTOPES; INJECTION; INTAKE; INTRAVENOUS INJECTION; ISOTOPE APPLICATIONS; ISOTOPES; KINETICS; LIGHT NUCLEI; LIPOTROPIC FACTORS; Male; MAMMALS; MAN; MASSACHUSETTS; men; METABOLISM; METABOLISME; METABOLISMO; Metabolisms and neurohumoral controls; METHIONINE; Methionine - administration & dosage; Methionine - analogs & derivatives; Methionine - blood; Methionine - metabolism; METHYLATION; METIONINA; Nitrogen metabolism. Proteins. Glycoproteins. Nucleic acids. Collagen; NUCLEI; NUTRITION; Nutritional Requirements; ODD-ODD NUCLEI; ORAL ADMINISTRATION; ORGANIC ACIDS; ORGANIC COMPOUNDS; ORGANIC SULFUR COMPOUNDS; ORINA; pharmacology; PLASMA SANGUIN; PLASMA SANGUINEO; PRIMATES; QUATERNARY COMPOUNDS; REACTION KINETICS; STABLE ISOTOPES; TRACER TECHNIQUES; URINE; VERTEBRATES 550501 > Metabolism > Tracer Techniques; Vertebrates: anatomy and physiology, studies on body, several organs or systems; young adults; Massachusetts; Human; Diet; Betaine; Aminoacid; Methionine; Adult; Male; Kinetics; Metabolism
• ISSN: 0002-9165; 1938-3207
• DOI: 10.1093/ajcn/54.2.386

The effects of a daily 3-g supplement of betaine on kinetic aspects of L-[2H3-methyl-1-13C]methionine (MET) metabolism in healthy young adult men were explored. Four groups of four subjects each were given a control diet, based on an L-amino acid mixture supplying 29.5 and 21.9 mg.kg-1.d-1 of L-methionine and L-cystine for 4 d before the tracer study, conducted on day 5 during the fed state. Two groups received the control diet and two groups received the betaine supplement. Tracer was given intravenously (iv) or orally. The transmethylation rate of MET (TM), homocysteine remethylation (RM), and oxidation of methionine were estimated from plasma methionine labeling and 13C enrichment of expired air. RM tended to increase (P = 0.14) but the TM and methionine oxidation were significantly (P 0.05) higher after betaine supplementation when estimated with the oral tracer. No differences were detected with the intravenous tracer. Methionine concentration in plasma obtained from blood taken from subjects in the fed state was higher (P 0.01) with betaine supplementation. These results suggest that excess methyl-group intake may increase the dietary requirement for methionine