title: Betaine supplementation decreases post-methionine hyperhomocysteinemia in chronic renal failure.
abstract: BACKGROUND
  Fasting and post-methionine load hyperhomocysteinemia are independent risk factors for vascular disease that are common in chronic renal failure. Folate decreases but seldom normalizes fasting total homocysteine (tHcy) concentrations in such patients. Glycine betaine (GB) is known to decrease tHcy in other clinical settings, but whether it is beneficial in chronic renal failure has not been established.
  
  
  METHODS
  We conducted a crossover-controlled trial in 36 patients with chronic renal failure to determine if oral GB decreased fasting or post-methionine tHcy concentrations. All subjects received, in randomized sequence, 5-mg folic acid and 50-mg pyridoxine daily, with or without GB 4-g daily, for three months each. Fasting plasma tHcy, GB, folate, B vitamins, serum lipids and creatinine were measured at one and three months, and methionine load tests were performed at the end of each three-month treatment phase.
  
  
  RESULTS
  GB and N,N-dimethylglycine (DMG) levels in plasma and urine increased markedly during GB treatment. Fasting tHcy decreased from baseline with both treatments but did not differ between treatments. Post-methionine tHcy decreased with both treatments and was 18% lower on GB than on folate and pyridoxine alone (P < 0.001). There were small increases in lipids during treatment with GB but the ratio of total: HDL cholesterol was unchanged.
  
  
  CONCLUSIONS
  GB supplementation had no effect on fasting tHcy in patients with chronic renal failure who were folate and pyridoxine replete, but it significantly decreased tHcy concentrations after methionine loading.
authors.affiliation: Department of Nephrology, Christchurch Hospital and School of Medicine, Private Bag 4710, Christchurch, New Zealand. david.mcgregor@cdhb.govt.nz
authors.forename: David O
authors.initials: DO
authors.lastname: McGregor
authors.forename: Warwick J
authors.initials: WJ
authors.lastname: Dellow
authors.forename: Richard A
authors.initials: RA
authors.lastname: Robson
authors.forename: Michael
authors.initials: M
authors.lastname: Lever
authors.forename: Peter M
authors.initials: PM
authors.lastname: George
authors.forename: Stephen T
authors.initials: ST
authors.lastname: Chambers
mesh_terms: D000368:Aged; D001622:Betaine / Q000097:blood / Q000627:therapeutic use*; D018592:Cross-Over Studies; D004359:Drug Therapy, Combination; D005215:Fasting / Q000097:blood; D005260:Female; D005492:Folic Acid / Q000627:therapeutic use; D006397:Hematinics / Q000627:therapeutic use; D006801:Humans; D020138:Hyperhomocysteinemia / Q000097:blood / Q000188:drug therapy* / Q000209:etiology*; D007676:Kidney Failure, Chronic / Q000150:complications*; D008055:Lipids / Q000097:blood; D008297:Male; D008715:Methionine; D008875:Middle Aged; D011736:Pyridoxine / Q000627:therapeutic use; D012521:Sarcosine / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D006397:Hematinics; D008055:Lipids; D001622:Betaine; C025138:dimethylglycine; D005492:Folic Acid; D008715:Methionine; D011736:Pyridoxine; D012521:Sarcosine