Effect of L-methionine supplementation on plasma homocysteine and other free amino acids: a placebo-controlled double-blind cross-over study

Objective: The essential amino acid L-methionine is a potential compound in the prophylaxis of recurrent or relapsing urinary tract infection due to acidification of urine. As an intermediate of L-methionine metabolism, homocysteine is formed. The objective was to study the metabolism of L-methionin...

Full description

Saved in:
Bibliographic Details
Published in:European journal of clinical nutrition 2005-06, Vol.59 (6), p.768-775
Main Authors: Ditscheid, B, Funfstuck, R, Busch, M, Schubert, R, Gerth, J, Jahreis, G
Format: Article
Language:English
Subjects:
Acidification
Adult
Aged
amino acid metabolism
Amino acids
Amino Acids - blood
Amino Acids - urine
Biological and medical sciences
blood chemistry
blood serum
chronic diseases
Chronic infection
Clinical trials
Cross-Over Studies
cystathionine
cystine
Dietary Supplements
Double-Blind Method
Double-blind studies
excretion
Female
Folic acid
Folic Acid - blood
free amino acids
Glycine
glycine (amino acid)
Homocysteine
Homocysteine - blood
Homocysteine - metabolism
Homocysteine - urine
Humans
L-methionine
Medical sciences
Metabolic diseases
Metabolism
Methionine
Methionine - blood
Methionine - pharmacology
Methionine - urine
Middle Aged
nutrient intake
Nutrition
nutritional intervention
Placebos
Prophylaxis
protein intake
protein supplements
Recurrent infection
Renal function
serine
Urinary tract
Urinary tract diseases
Urinary tract infections
Urinary Tract Infections - blood
Urinary Tract Infections - prevention & control
Urinary Tract Infections - urine
urine
Urogenital system
Vitamin B 12 - blood
Vitamin B 6 - blood
Vitamin B12
vitamin intake
Vitamins
women
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Objective: The essential amino acid L-methionine is a potential compound in the prophylaxis of recurrent or relapsing urinary tract infection due to acidification of urine. As an intermediate of L-methionine metabolism, homocysteine is formed. The objective was to study the metabolism of L-methionine and homocysteine, and to assess whether there are differences between patients with chronic urinary tract infection and healthy control subjects. Design: A randomized placebo-controlled double-blind intervention study with cross-over design. Setting: Department of Nutritional Physiology, Institute of Nutrition in cooperation with the Department of Internal Medicine III, Friedrich Schiller University of Jena, Germany. Subjects: Eight female patients with chronic urinary tract infection and 12 healthy women (controls). Interventions: After a methionine-loading test, the volunteers received 500 mg L-methionine or a placebo three times daily for 4 weeks. Main outcome measures: Serum and urinary concentrations of methionine, homocysteine, cystathionine, cystine, serine, glycine and serum concentrations of vitamin B12, B6 and the state of folate. Results: Homocysteine plasma concentrations increased from 9.4+/-2.7 micromol/l (patients) and 8.9+/-1.8 micromol/l (controls) in the placebo period to 11.2+/-4.1 micromol/l (P=0.031) and 11.0+/-2.3 micromol/l (P=0.000), respectively, during L-methionine supplementation. There were significant increases in serum methionine (53.6+/-22.0 micromol/l; P=0.003; n=20) and cystathionine (0.62+/-0.30 micromol/l; P=0.000; n=20) concentrations compared with the placebo period (33.0+/-12.0 and 0.30+/-0.10 micromol/l; n=20). Simultaneously, renal excretion of methionine and homocysteine was significantly higher during L-methionine intake. Conclusions: Despite an adequate vitamin status, the supplementation of 1500 mg of L-methionine daily significantly increases homocysteine plasma concentrations by an average of 2.0 micromol/l in patients and in control subjects. An optimal vitamin supplementation, especially with folate, might prevent such an increase.
ISSN:0954-3007
1476-5640
DOI:10.1038/sj.ejcn.1602138