title: Sex and menopausal status influence human dietary requirements for the nutrient choline.
abstract: BACKGROUND
  Although humans require dietary choline for methyl donation, membrane function, and neurotransmission, choline can also be derived from the de novo synthesis of phosphatidylcholine, which is up-regulated by estrogen. A recommended Adequate Intake (AI) exists for choline; however, an Estimated Average Requirement has not been set because of a lack of sufficient human data.
  
  
  OBJECTIVE
  The objective of the study was to evaluate the dietary requirements for choline in healthy men and women and to investigate the clinical sequelae of choline deficiency.
  
  
  METHODS
  Fifty-seven adult subjects (26 men, 16 premenopausal women, 15 postmenopausal women) were fed a diet containing 550 mg choline x 70 kg(-1) x d(-1) for 10 d followed by <50 mg choline x 70 kg(-1) x d(-1) with or without a folic acid supplement (400 microg/d per randomization) for up to 42 d. Subjects who developed organ dysfunction during this diet had normal organ function restored after incremental amounts of choline were added back to the diet. Blood and urine were monitored for signs of toxicity and metabolite concentrations, and liver fat was assessed by using magnetic resonance imaging.
  
  
  RESULTS
  When deprived of dietary choline, 77% of men and 80% of postmenopausal women developed fatty liver or muscle damage, whereas only 44% of premenopausal women developed such signs of organ dysfunction. Moreover, 6 men developed these signs while consuming 550 mg choline x 70 kg(-1) x d(-1), the AI for choline. Folic acid supplementation did not alter the subjects' response.
  
  
  CONCLUSIONS
  Subject characteristics (eg, menopausal status) modulated the dietary requirement for choline, and a daily intake at the current AI was not sufficient to prevent organ dysfunction in 19 of the subjects.
authors.affiliation: Department of Nutrition, School of Public Health and School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7461, USA.
authors.forename: Leslie M
authors.initials: LM
authors.lastname: Fischer
authors.forename: Kerry Ann
authors.initials: KA
authors.lastname: daCosta
authors.forename: Lester
authors.initials: L
authors.lastname: Kwock
authors.forename: Paul W
authors.initials: PW
authors.lastname: Stewart
authors.forename: Tsui-Shan
authors.initials: TS
authors.lastname: Lu
authors.forename: Sally P
authors.initials: SP
authors.lastname: Stabler
authors.forename: Robert H
authors.initials: RH
authors.lastname: Allen
authors.forename: Steven H
authors.initials: SH
authors.lastname: Zeisel
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002794:Choline / Q000008:administration & dosage* / Q000378:metabolism / Q000493:pharmacokinetics; D002796:Choline Deficiency / Q000150:complications* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005234:Fatty Liver / Q000209:etiology* / Q000378:metabolism; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage / Q000494:pharmacology; D006801:Humans; D008297:Male; D008593:Menopause / Q000502:physiology*; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000201:enzymology / Q000378:metabolism / Q000473:pathology*; D018673:Nutrition Policy; D009751:Nutritional Requirements; D010713:Phosphatidylcholines / Q000378:metabolism; D012737:Sex Factors
chemical_list: D010713:Phosphatidylcholines; D005492:Folic Acid; D002794:Choline