title: Choline and vitamin B12 deficiencies are interrelated in folate-replete long-term total parenteral nutrition patients.
abstract: BACKGROUND
  Choline has recently been recognized as an essential nutrient, in part based on deficiency data in long-term home total parenteral nutrition (TPN) patients. Choline, a methyl donor in the metabolism of homocysteine, is intricately related to folate status, but little is known about choline and vitamin B12 status. Long-term TPN patients are also subject to vitamin B12 deficiency.
  
  
  OBJECTIVE
  The objective of the study was to evaluate any interaction between choline, vitamin B12, and folate in patients with severe malabsorption syndromes, requiring long-term TPN.
  
  
  METHODS
  Plasma free choline, serum and red blood cell (RBC) folate, serum vitamin B12 methylmalonic acid, B6, and plasma total homocysteine concentrations were assayed by standard methods. Low choline was defined as values that fall 1 to < or =3 and marked low choline concentration as >3 SD below the control mean.
  
  
  RESULTS
  Both low choline concentrations (52% were marked low, 33% low, 14% normal) and elevated methylmalonic acid concentrations (47%) were prevalent. Choline concentration was significantly lower and RBC folate higher in patients with elevated methylmalonic acid. Total homocysteine elevations were rare (3 of 21) and mild.
  
  
  CONCLUSIONS
  These data suggest a strong interaction between vitamin B12 and choline deficiencies and folate status in this population, which may be due in part to variations in vitamin and choline delivery by TPN. Folate adequacy may increase B12 use for homocysteine metabolism, thus limiting B12 availability for methylmaIonic acid metabolism. Choline use may also increase, and choline deficiency may worsen if choline substitutes when the vitamin B12 side of the homocysteine metabolic pathway cannot be used.
authors.affiliation: Clinical Nutrition Support Service, University of Pennsylvania, Philadelphia 19104, USA. compherc@nursing.upenn.edu
authors.forename: Charlene W
authors.initials: CW
authors.lastname: Compher
authors.forename: Bruce P
authors.initials: BP
authors.lastname: Kinosian
authors.forename: Nancy E
authors.initials: NE
authors.lastname: Stoner
authors.forename: Deborah C
authors.initials: DC
authors.lastname: Lentine
authors.forename: Gordon P
authors.initials: GP
authors.lastname: Buzby
mesh_terms: D002794:Choline / Q000097:blood*; D002796:Choline Deficiency / Q000097:blood* / Q000175:diagnosis; D005260:Female; D005492:Folic Acid / Q000097:blood*; D006710:Homocysteine / Q000378:metabolism; D006801:Humans; D008297:Male; D008764:Methylmalonic Acid / Q000097:blood; D008875:Middle Aged; D009752:Nutritional Status; D016562:Parenteral Nutrition, Home Total / Q000009:adverse effects*; D015995:Prevalence; D014806:Vitamin B 12 Deficiency / Q000097:blood* / Q000175:diagnosis
chemical_list: D006710:Homocysteine; D008764:Methylmalonic Acid; D005492:Folic Acid; D002794:Choline